The alkali metals are the series of elements in Group 1 (IUPAC style) of the periodic table (excluding hydrogen in all but one rare circumstance): lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). They are all highly reactive and are rarely found in elemental form in nature. As a result, they are stored under mineral oil. They also tarnish easily and have low melting points and densities. Potassium and Rubidium are very weakly radioactive (harmless) due to the presence of long duration radioactive isotopes.
The alkali metals are silver-colored (caesium has a golden tinge), soft, low-density metals, which react readily with halogens to form ionic salts, and with water to form strongly alkaline (basic) hydroxides. These elements all have one electron in their outermost shell, so the energetically preferred state of achieving a filled electron shell is to lose one electron to form a singly charged positive ion.
Hydrogen, with a solitary electron, is usually placed at the top of Group 1 of the periodic table, but it is not considered an alkali metal; rather it exists naturally as a diatomic gas. Removal of its single electron requires considerably more energy than removal of the outer electron for the alkali metals. As in the halogens, only one additional electron is required to fill in the outermost shell of the hydrogen atom, so hydrogen can in some circumstances behave like a halogen, forming the negative hydride ion. Binary compounds of hydride with the alkali metals and some transition metals have been prepared.
Under extremely high pressure, such as is found at the core of Jupiter, hydrogen does become metallic and behaves like an alkali metal; see metallic hydrogen.
Alkali metals are highly reactive. They have the lowest ionization potentials in their respective periods, as removing the single electron from the outermost shell gives them the stable inert gas configuration. But their second ionization potentials are very high, as removing an electron from a species having a noble gas configuration is very difficult.
Contents [hide]
1 Reactions
1.1 Reactions in water
1.2 Reaction in ammonia
2 See also
3 External links
[edit] Reactions
[edit] Reactions in water
Alkali metals are famous for their vigorous reactions with water, and these reactions become increasingly violent as one moves down the group. The reaction with water is as follows:
Alkali metal + water → Alkali metal hydroxide + hydrogen
With potassium as an example:
2K (s) + 2H2O (l) → 2KOH (aq) + H2 (g)
In this reaction, enough energy is produced to ignite the hydrogen, creating a lilac flame above the potassium.
[edit] Reaction in ammonia
Alkali metals dissolve in liquid ammonia to give blue solutions that are paramagnetic. Saturated solutions are a deep purple color.
K (s) + NH3 (l) → K+ (aq) + e- (aq)
The free electrons the solution occupies more space than the sum of the volumes of the metal and ammonia. The free electrons also makes these solutions very good reducing agents. Since they are easier to handle than the metals themselves they are sometimes used as substitutes.
.1 Purpose and Scope
Alkali metals (lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and the unstable element francium (Fr)) and their alloys are used in various LLNL operations. This document describes the hazardous properties of these materials and their reactive compounds (e.g., hydrides, oxides, and peroxides). It also provides controls for working with these alkali materials and the responsibilities of Laboratory organizations involved in the procurement, receipt, transport, use, storage and disposal of such materials.
Appendix A contains requirements for handling waste alkali metals and equipment contaminated with such materials.
1.2 Characteristics
Alkali metals and their alloys demonstrate good electrical and heat conductivity and are often used in their molten state. Thus, they are commonly referred to as "liquid metals." Cesium melts at 28°C (82.4°F)--just above room temperature. The NaK alloy most commonly used consists of 78% potassium and is liquid down to - 12.6°C (9.32°F)--well below room temperature. All other alkali metals have relatively low melting points and high boiling points (see Table 1 for physical constants). Pure alkali metals are soft and ductile at room temperature (Cs may be liquid at 28°C or 82.4°F) and silver in color--except for Cs, which is golden when newly cut but will rapidly oxidize turning gray.
Table 1. Approximate physical constants of alkali metals and NaK alloy (78 % K and 22 % Na).
Cs
Rb
K
Na
Li
NaK
Atomic weight
133
85.5
39
23
6.9
35.48
Melting Point, °C (°F)
28
(82.4)
39
(102.2)
63
(145.4)
153
(307.4)
179
(354.2)
-12.6
(9.32)
Boiling Point, °C (°F)
682
(1259.6)
688
(1270.4)
760
(1400)
881
(1617.8)
1338
(2440.4)
785
(1445)
Specific Gravity
1.87
1.53
0.86
0.97
0.53
0.73
Oxidation Potential, volts, M -> M+ + e-
3.026
2.98
2.931
2.71
3.041
n/a
Alkali metals form an almost unlimited variety of compounds with simple ions (e. g., chloride, nitrate), complex ions (e. g., ferrocyanide), and organic materials (e. g., oxalate). In many of these, the alkali metal ion simply serves as a counter ion and presents no hazard from a reactivity or toxicity perspective. In other compounds, such as the common laboratory and industrial chemicals NaOH and KOH, significant potential hazards and environmental aspects may exist, but they are well understood and readily addressed by standard chemical or industrial practice.
Other, more reactive compounds, such as LiAlH4, NaBH4, LiH (commonly referred to as "salt"), or NaH may present special hazards and environmental aspects depending on the specific situation. The reactivity is due to the nature of the hydride and not the alkali metal. Compounds like the simple hydrides react with active hydrogens (water, acids, alcohols, and others) according to the following:
NaH + H+ ->Na+ + H2
Eo= -2.25 volt
Which indicates that these compounds are extremely powerful reducing agents. Although the stability of the hydrides themselves vary substantially: LiH can be melted without decomposition in the absence of air or oxygen (it is also possible to disassociate LiH into lithium and hydrogen). Reaction of LiH with air is variable: massive (or "chunks") react slowly producing a LiOH/H2O surface layer which slows further reaction, finely divided LiH reacts much faster and may be pyrophoric.
LiAlH4 and NaBH4 are frequently encountered in synthetic chemistry where they are useful reducing agents. The reactivity of these kinds of compounds is highly variable: NaBH4 is soluble in water with slight hydrolysis, NaAlH4 dissolution and hydrolysis is rapid (and may be explosive).
2.0 Hazards
Alkali metals are highly reactive and therefore will never be found in nature in their pure state. Pure alkali metals are not considered "toxic" in the usual sense of the word, because it is virtually impossible to inhale or ingest the pure metal. However, reaction products, which can be produced when alkali metals come in contact with the human body or other materials, can be toxic, flammable, and corrosive. The subsections below describe the hazards and reactions of alkali metals with various substances.
2.1 Reaction of Alkali Metals with Oxygen
Cesium, Rb, and presumably Fr react vigorously with oxygen at room temperature to form the metal oxide, which results in a self-sustaining metal fire that rapidly heats up to almost 1980°C (3596°F)
Liquid NaK may ignite spontaneously in the atmosphere at room temperature.
Potassium is less reactive at room temperature and generally will not ignite spontaneously.
Bulk Sodium and Li will not result in a fire because they are even less reactive, and oxidation occurs slowly. However, if these less reactive metals are finely divided or molten and are exposed to oxygen, spontaneous ignition may occur and a self-sustaining fire could develop.
In each case, the resulting metal oxide immediately condenses to form a dense, white fume that is highly corrosive to the lungs, eyes, and skin--where metal oxide forms metal hydroxide. These fumes can obscure vision if not contained.
Under various circumstances, alkali metals (except Li and rarely Na) if cut or scraped may react to form unstable, higher oxides (e.g., peroxides or superoxides) that may react if cut or scraped. These higher oxides can react with the base metal or organic materials in an explosive manner or can start a fire. In some cases, they may be shock sensitive.
2.2 Reaction of Alkali Metals with Water
Alkali metals react vigorously with water to release hydrogen and form the corresponding hydroxide (e.g., sodium hydroxide), resulting in an alkaline (basic) solution. The rate of reaction increases as the atomic weight increases.
Lithium reacts the slowest and poses the least hazard.
The other metals react very quickly, generating great heat and splattering with the possible destruction of experimental apparatus. Hydrogen gas is also released in this reaction, and the heat can ignite the hydrogen resulting in a fire or an explosion. The broad explosive range of hydrogen (4-75%) makes this reaction very difficult to control.
2.3 Reaction of Alkali Metals with Other Materials
Molten alkali metals react with other materials as follows:
Explosively with hydrogen forming toxic hydrides (e.g., lithium hydride).
Vigorously with carbon tetrachloride and other halogenated hydrocarbons and plastics (e.g., Teflon and polyvinyl chloride), possibly creating an explosion and generating toxic gaseous byproducts (e.g., phosgene, perfluoroisobutylene, and acid gases).
Vigorously with organic alcohol (the reaction rate decreases as the molecular weight increases), unsaturated organic materials, most inorganic acids, and carbon dioxide.
Violently with organic acids and some metallic halides (e.g., mercuric chloride) upon impact.
At high temperature, lithium reacts with atmospheric nitrogen, nitrogen containing organic materials, and glass that may result in the failure of glass containers.
2.4 Reaction of Alkali Metal Compounds
The reactivity of alkali metal compounds is highly variable and is dependent on the specific compound and on many factors which include, but is not limited to, the availability of active hydrogens and water, presence of unsaturated functional groups, presence of oxygen, temperature, particle size and other factors.
3.0 Controls for Working with Alkali Metals
The three methods for mitigating hazards and negative environmental impact associated with alkali metals are engineered controls, administrative controls, and personal protective equipment. Engineered controls are the preferred means of mitigating hazards and are supplemented by the other controls as necessary. In practice, however, all of these methods are usually implemented when alkali metals are in use. The method appropriate for any experiment usually is determined by an ES&H evaluation(s) and incorporated into the hazard analysis, Integration Work Sheet (IWS) or in a safety plan (SP), if applicable.
This section contains the engineered controls, administrative controls, and personal protective equipment required for work with alkali metals.
3.1 Engineered Controls
3.1.1 Design Criteria
The following criteria apply when designing equipment for use with alkali metals:
Equipment that contains alkali metal shall be designed such that it can withstand the highest anticipated reaction temperature.
Packless valves and seamless welded tubing should be used for liquid metal systems. Unwelded joints shall be encased in a secondary containment.
Secondary containment shall be placed under experimental apparatus that use liquid metals (e.g. steel-drip pans with oxygen limiting perforated covers.
Systems with liquid metals should be designed so that, in the event of a shut down, all of the metal flows by gravity to a single low point where it can be removed. A system for removing oxides that may form during the use of liquid metals should be included in the design.
Where liquid metals other than NaK are in use, adequate heating shall be distributed to all parts of the system to prevent the metal from freezing at a cold spot. Electrical trace heating or other means may be acceptable, but steam or water heating is prohibited. Precautions shall be taken to ensure that water does not come in contact with alkali metals.
An adequate ventilation system that is capable of capturing all evolved metal oxide or hydrogen in the worst-case accident scenario shall be provided for operations involving more than small amounts of alkali metals. The need for a dedicated system shall be evaluated. Compatibility of materials exhausted with other contaminants in the ventilation system shall be evaluated. It shall exhaust through a stack of sufficient height and distance that will prevent fumes from re-entraining into building air intakes and the levels of metal oxide on the building roof (or in other areas surrounding the building) from exceeding the ACGIH threshold limit values. A scrubber capable of removing most of the noxious metal oxide in the worse design-base accident may reduce the required stack height. Scrubbers shall be provided with emergency power.
Systems with liquid metals shall have overpressure vents that are vented into the exhaust system.
Where quantities of liquid metal exceeding 1 kg are in use, the ventilation system shall have emergency power.
Inert gas blankets shall have less than
35 mg/m3 of water vapor,
0.5% oxygen,
1.5% hydrogen.
Nitrogen shall not be used for operations involving liquid Li.
Appropriate leak-detection equipment with alarms should be considered.
Metal-handling systems should include features that allow for simplified dismantling and decontamination. See Appendix A for the requirements on handling equipment contaminated with alkali metals.
3.1.2 Transportation and Transfer of Alkali Metals
Transportation/Transfer is divided into three categories for discussion in this document. The three categories are: Incoming Transportation, On-Site Transfer, and Outgoing Transportation.
Incoming Transportation. Incoming shipments meet the requirements in 49 CFR 173.212, and alkali metals shall always be transported in their original containers. The Material Distribution Division shall deliver alkali metals (except for hazardous waste) to on-site requesters.
On-Site Transfer. Lithium, Na, and NaK, and to a lesser degree K, can be transferred in air or under oil or kerosene, as appropriate, because the rate of oxidation is fairly slow. The container shall be labeled per the storage requirements in Section 3.1.3.
All other alkali metals shall be transferred in an inert atmosphere (e.g., in a dry argon-filled or vacuum container or glove box made of materials that are compatible with the metal) to prevent exposure to air, water, or other incompatible material. The container shall be labeled per the storage requirements in Section 3.1.3.
Nitrogen may be used with alkali metals, except when handling Li because it reactively forms ruby-red Li3N, which also is extremely reactive and may be shock sensitive.
The Responsible Individual owning the alkali metal shall verify that the individual requesting the transfer has an approved IWS or safety plan and proper facilities available before making the transfer. Trained and authorized personnel may hand carry (walk) properly packaged alkali metals from one facility to another. If any vehicle is to be used for the transfer, it shall be properly placarded. Contact either Materials Management or Materials Distribution for the correct requirements and placard materials. These organizations may, with advance notification, provide a placarded vehicle. For more information on other methods available for the safe transfer of solid and liquid metals, contact the area ES&H Team.
Outgoing Transportation. When alkali metals are to be shipped off site, the Responsible Individual who owns the material shall package the material in a suitable primary container (not glass), sealed with the appropriate noble gas atmosphere, oil or kerosene. The primary container shall be labeled per the storage requirements in Section 3.1.3, except that the date packed shall be used instead of the date received. If the detailed packing requirements for the particular alkali metal are not contained in the FSP, an IWS shall be prepared stating those requirements. This IWS shall be reviewed and approved by the ES&H Team. The primary package of the alkali metal may then be transferred to Materials Distribution Shipping Section so that the DOT-approved secondary packaging and labeling can be completed.
3.1.3 Storage
Alkali metals shall be stored in areas where they are free of moisture, oxygen, and, in the case of Li, nitrogen. Metals should be stored in containers supplied by the manufacturer, or as stipulated in the hazard review or SP, under mineral oil or kerosene, or in containers that are evacuated or filled with a noble gas. Even under such storage conditions, some oxide or hydroxide may be formed because of liquid or oxygen in the mineral oil or because of leakage into the inert atmosphere container.
Only the amount of alkali metal necessary to perform the work should be removed from storage. Spare materials shall be returned to the appropriate storage container, and the container to its appropriate location.
Storage containers shall be labeled to indicate their contents, the hazards properties, date received, weight of the metal, and type of oil or gas used to inert the metal. Furthermore, these containers should be stored individually or in a manner that allows visual inspection for container integrity.
Storage areas shall be free of combustibles and of ignition sources.
Building or portions of the building dedicated as storage area for alkali metals shall not be equipped with automatic sprinklers (except for the Materials Management Division Vaults). No other source of water (e.g., showers, sinks) shall be in the immediate proximity of the metal.
Storage areas shall be prominently labeled to indicate the presence of alkali metals. Up to 5 kg of alkali may be stored in a flammable storage locker inside a building. Quantities exceeding 5 kg shall be stored in separate structures that are noncombustible (e.g., steel transportainers).
3.2 Administrative Controls
3.2.1 Safety Plans
An ES&H evaluation (IWS) is required for the following work:
Operations involving the use of alkali metals in their molten state. An IWS/SP or FSP will be required for other than small amounts.
All uses of Cs, NaK, and Rb. An IWS/SP or FSP is required for any amount of material.
Use of other than small amounts of Li, Na, or K. Amounts exceeding 500 g during the entire experiment or for a period of one year, whichever is less, may require an IWS/SP or FSP.
Any changes in previously approved work that may increase the potential risk.
3.2.2 Literature Review
Prior to beginning work with reactive alkali metal compounds, a thorough literature review should be conducted to assess reactivity and incompatibilities. Useful sources include the standard texts for organic and inorganic chemistry, and the chemical research periodicals.
3.2.3 Training
All workers who handle alkali metals in quantities that require a safety plan shall complete course HS4260 (Alkali Metals) offered by the Hazards Control Department. Moreover, these workers shall be familiar with the IWS and applicable safety plans (FSP or IWS/SP) before beginning work with alkali metals.
3.2.4 ES&H Review
The Responsible Individual shall perform a careful hazards and environmental aspects review of the design, construction, operation, and ultimate dismantling upon completing experiments involving alkali metals. After the controls have been established, the safety plans and procedures are written and approved, and the personnel are trained, the Responsible Individual shall contact the area ES&H Team Leader, who shall arrange to have the operation reviewed by appropriate discipline personnel (usually an industrial hygienist, a fire protection engineer, and an environmental analyst).
3.2.5 Isolation
Many chemicals react with alkali metals. However, these metals are generally benign as long as they are kept away from the materials with which they react (e.g., oxygen, water, acids, halogenated hydrocarbons, and carbon dioxide). The fundamental principle is to isolate alkali metals (both in the solid and molten state) from reactive materials.
General traffic is prohibited in areas where alkali metal operations are performed. The appropriate warning signs shall be posted in these areas limiting access to authorized personnel. Further access controls, up to and including run-safe boxes, may be necessary and should be stipulated in the IWS/SP.
3.2.6 Handling
The following requirements apply when handling alkali metals:
Skin and eye contact with alkali metals shall be avoided. Where possible, tongs or other appropriate tools should be used to handle solid alkali metals. Syringes or other means should be used for liquid metals to prevent skin contact (see discussion in this section). Oxidized materials (white or gray surface coating) may make the metal more hazardous to handle. Materials with a yellow or orange coating may indicate the presence of peroxides or superoxides, which may be explosive if cut or abraded. These materials should not be used; they should be isolated and disposed of promptly. Contact your area ES&H Team for assistance.
All tools used to handle alkali metals shall be dry, rust-free, clean, and composed of a material compatible with the metal. Tools can be dried by baking in an oven, desiccating in a vacuum, or rubbing with anhydrous dry soda ash.
Containers with alkali metals shall be assumed to contain flammable hydrogen gas in the headspace, even if stored under mineral oil or inert gas. Thus, no ignition source shall be present where these containers are opened. Tools used to open the containers shall be of the sparkless variety.
Areas where any alkali metal is handled shall be free of ignition sources. Glove boxes, hoods, or other similar apparatus shall have explosion-proof Class 1, Division 1, Group B electrical systems.
An emergency eyewash/safety shower unit shall be available in all work areas where alkali metals are in use. This unit shall be positioned far enough away from alkali metal work so that a system failure will not pose a hazard, but near enough for quick access in the event of an emergency.
3.2.7 Procurement
The Responsible Individual (e.g., experimenters and other designated workers) shall purchase all alkali metals through the Procurement & Materiel (P&M) Department, noting the pyrophoric nature of the material on the requisition. Unicard shall not be used to purchase alkali metals in quantities greater than 500 g. The Material Distribution Division shall receive and deliver all alkali metals in their original containers to the requester.
3.3 Personal Protective Equipment
Engineering controls greatly reduce the need for personal protective equipment when handling alkali metals. Under all circumstances where alkali metals are in use, the PPE described below is required as a minimum.
An easily removable laboratory coat (or equivalent).
Chrome leather gloves or appropriate rubber gloves.
Safety glasses (other protective eyewear such as chemical goggles and face shield may be required, based on the task.)
Where solid metal is handled without a barrier, a fire retardant apron and protective eyewear are required. Additional personal protective equipment shall be stipulated in the IWS/SP in cases where large quantities of solid and liquid alkali metals are in use.
3.4 Fire and Spill Emergency Preparedness
The appropriate material shall be available to extinguish fires and contain alkali metal spills. Met-L-X, anhydrous dry soda ash, powdered graphite may be used for all alkali metals except Li. This material shall be kept in a sealed, labeled yellow container to prevent contamination and to keep it moisture-free. Only Lith-X fire extinguishers shall be used for Li fires. Workers involved in alkali metal work shall be trained to use these extinguishing materials.
Only trained personnel using personal protective equipment (as specified in the IWS, SP or other hazard review document) shall attempt to control small, contained fires or spills. Large or uncontained fires or spills, or fires where the ventilation system does not contain all of the fumes, shall be handled only by the Fire Department. Before attempting to extinguish a metal fire or contain a spill, notify the fire dispatcher (dial 911).
3.5 Skin or Eye Contact Emergency Preparedness
If any alkali metal fragment or liquid enters the eye, it will immediately react generating considerable heat and hydroxide and likely result in severe eye damage. In such cases, the eyes shall be flushed with water from an eyewash/safety shower. Continue to flush the eye with water while someone dials 911 for emergency help.
When alkali metal comes in contact with the skin through clothing, the first response is to remove the contaminated clothing. Take extra precautions for fire and hazardous materials when handling contaminated clothing. Dial 911 for assistance.
If the alkali metal has already burned off (e.g., Rb and Cs will burn spontaneously), the victim should be drenched continually under a safety shower until emergency help arrives.
If the material is not burning (perhaps Na or Li scraps), the visible metal particulates should be removed immediately using tweezers, tongs, a scrapper or swab. The metal particulates shall be stored in either kerosene or mineral oil to avoid further reactions. The victim should be drenched continually under a safety shower until emergency help arrives.
If the material is not burning and the fragments are embedded into the skin, burn areas should be covered with mineral oil to insulate the unreacted fragments from water (References 1-3). The patient shall be transported promptly to a treatment facility, where the wound would be debrided and the remaining fragments removed. When it is certain that all metal fragments have been removed, the wound area may be irrigated with water.
4.0 Responsibilities
All workers and organizations shall refer to Document 2.1, "General Worker Responsibilities and Integrated Safety Management" in the ES&H Manual for a list of general responsibilities. The specific responsibilities for individuals and organizations that work with alkali metals are listed under each title below.
4.1 Responsible Individual
Ensure the following:
A complete ES&H evaluation (IWS) of the proposed operation (including a review by the ES&H Team) is conducted as described in Document 2.2, "Managing ES&H for LLNL Work," in the ES&H Manual before starting the experiment.
Personnel who work with alkali metals in quantities that require a safety plan shall complete course HS4260, "Alkali Metals." This course is offered by the Hazards Control Department.
Where required, an Engineering Safety Note (ESN) is developed and referenced in the SP for cases where liquid or solid metals are used and the safety analysis indicates a need for the document.
Workers comply with all requirements of the IWS, ESN and SP. Workers shall also follow the procedures specified in this document for all purchases of alkali metals. Purchases shall be made through the Procurement & Materiel Department, and the requisition should indicate that an alkali metal is being purchased.
The storage, handling, and disposal of alkali metals meet the requirements of this document and other requirements in the ES&H Manual.
Notify ChemTrack when alkali metals are received, so that the proper barcodes can be applied.
All engineering controls (e.g., ventilation, inert gases) function properly.
PPE is provided to workers who handle alkali metals.
Only appropriate types of fire extinguishers are present in the work area where alkali metals are in use.
First-aid equipment (e.g., tweezers, swabs, and at least one quart of mineral oil) is available in alkali metal work areas.
Prepare an SP for all uses of molten alkali metals; for solid Li, Na, or K that exceeds 500 g during the entire experiment or for a period of one year, which ever is less; for any amount of Cs, Rb, or NaK; or where the ES&H evaluation so indicates.
Contact the area ES&H Team before cleaning or dismantling any liquid metal handling system, unless procedures for such are already addressed in an SP. See Appendix A for requirements on handling equipment contaminated with waste alkali metals.
4.2 Hazards Control Department
Conduct hazard reviews of proposed, new or revised uses of alkali metals when requested or as required.
Assist in the design of safety-related systems and in the preparation and review of SPs.
Review ESNs associated with liquid metal systems.
Administer course HS4260, "Alkali Metals ," as required.
Evaluate roof access classification changes that may result from the use of alkali metals.
Review the implementation of hazard mitigation procedures and the equipment, and notify the Responsible Individual of any deficiencies.
Respond to spills, fires, exposures, or other emergencies involving alkali metals.
Review all requisitions for alkali metals received from the Procurement & Materiel Department (P&M) in accordance with the requirements of this document. Ensure that an IWS or safety plan (as appropriate) and other requirements have been met before the material may be ordered. Advise P&M when they can place the order.
Ensure that the Fire Department is equipped to handle large-scale alkali metal fires onsite at all times.
4.3 Material Distribution Division
Receive incoming shipments of alkali metals in accordance with the requirements of this document.
Inspect incoming shipments of alkali metal containers for signs of failure (e.g., leakage). Notify the area ES&H Team if a container is damaged or corroded, or call 911 if a spill occurs.
Deliver alkali metals to the requester in its original container.
Prepare secondary (but not primary) packaging for outgoing shipments of alkali metals. Comply with DOT transportation requirements for alkali metals.
4.4 Environmental Protection Department
Conduct a hazard review to evaluate environmental contamination problems, permit requirements, NEPA declarations, and other environmental issues during the experimental design phase.
Specify requirements for packaging waste alkali metals or equipment contaminated with such materials.
Remove and dispose of packaged waste alkali metals.
Properly handle contaminated equipment for disposal.
4.5 Facility Point of Contact
Maintain awareness of all operations involving alkali metals in your area of cognizance.
Contact the ES&H Team to determine if the roof access classification of the building has changed. This is required for areas whose alkali metal system has a ventilation system.
4.6 Health Services Department
Specify first-aid requirements for accidental exposures that involve alkali metals or their oxides or hydroxides.
Maintain appropriate facilities for immediate support of individuals exposed to alkali metals or their alloys.
4.7 Mechanical Engineering
Mechanical Engineering shall assist Responsible Individuals with preparing ESNs pertaining to the design of alkali metal handling systems.
4.8 Procurement & Materiel Department
Refer all requests for alkali metals, in quantities greater than 500 grams, to the cognizant Hazards Control Team for review of requirements, before placing the order for the material.
5.0 Work Smart Standards
ACGIH TLVs and BEIs: Threshold Limit Values for Chemical Substances and Physical Agents, 2004 (excluding Biological Exposure Indices, TLVs for Physical Agents, and Biologically Derived Airborne Contaminants).
DOE O 440.1A, Worker Protection Management for DOE Federal and Contractor Employees, Attachment 2, "Contractor Requirement Document," §§ 1-11, 13-18 (delete item 18.a), 19 (delete item 19.d.3) and 22,
DOE O 5480.19, Chg 1, Conduct of Operations Requirements for DOE Facilities.
DOE-HDBK-1081-94, Primer on Spontaneous Heating and Pyrophoricity.
49 CFR 173. 212, Non-bulk packagings for solid hazardous materials in Packing Group II.
22 CCR §§ 66261.1-66261.126 and appendices, Identification & Listing of Hazardous Waste.
22 CCR §§ 66262.10-66262.89, Standards Applicable to Generators of Hazardous Waste.
6.0 References
1. Anderson, F. A., A Primer for the Safe Use of Liquid Alkali Metals, Oak Ridge National Laboratory, Tennessee, ORNL-TM-1740, January 1967.
2. Clare, R. A and Krenzelok, E.P. Chemical Burns Secondary to Elemental Metal Exposure: Two Cases Report, American Journal of Emergency Medicine 6(4), 355-7 (July 1988).
3. Krenzelok, E. P. Sodium and Potassium, In Hazardous Materials Toxicology -- Clinical Principles of Environmental Health, Sullivans, J. B and Krieger, G. R. eds.
7.0 Resources for More Information
7.1 Contacts
See the ES&H Contact List.
7.2 Applicable Lessons Learned
Applicable lessons learned can be found at the following Internet address:
http://www-r.llnl.gov/es_and_h/lessons/lessons.shtml
7.3 Other Sources
8 CCR § 5176, Pyrophoric Materials (contains a few common-sense requirements that are incorporated into this document).
Bretherick, L., Handbook of Reactive Chemical Hazards, 4th edition (Butterworth's, London, 1990)
Furr, K. A., ed., CRC Handbook of Laboratory Safety: Reactive Metals (CRC Press, Inc., Florida, 1990) pp. 288-289.
Il'ya I., Superoxides of Alkali and Alkaline Earth Metals. Peroxides, Superoxides and Ozonides of Alkali and Alkaline Earth Metals, (Plenum Press, New York, 1966) pp. 2:102-124.
Jackson, C. B., ed., Liquid Metals Handbook and Supplements (U.S. Atomic Energy Commission, U.S. Government Printing Office, Washington, DC, 1954, 1955).
Jercinovic, L. M., ed., Accident Information: Lithium-Trichloroethylene Incident. (National Safety Council, Chicago, 1975).
Luigi, P., ed., Encyclopedia of Occupational Health and Safety: Metals, Alkali and Compounds (International Labour Office, Switzerland, 1983), pp. 1342-1344.
MSA Research Corporation, Nak. (MSA Research Corporation, Pennsylvania, 1966). National Safety Council, Sodium, (NSC, Chicago, 1956).
National Fire Protection Association. Fire Protection Guide to Hazardous Materials (NFPA, Boston, latest edition).
NFPA 485, Standard for the Storage, Handling, Processing, and Use of Lithium Metal.
Sittig M., Safe Handling of Alkali Metals, Industrial and Engineering Chemistry, 48(2), 227-229, 1956.
U.S. Division of Operational Safety. Big K: Chemical Commotion. Health and Safety Information, U.S. Atomic Energy Commission, 207. Washington, DC, 1965.
Appendix A
Requirements for Handling Equipment
Contaminated with Waste Alkali Metals
A.1 Disposal of Waste Alkali Metals
Waste alkali metals or equipment contaminated with such materials shall be packaged in accordance with DOT requirements. Contact your area ES&H Team or the radioactive and hazardous waste technician for specific assistance.
A.2 Decontaminating, Recycling, and Disposing of Contaminated Equipment
The Responsible Individual shall decontaminate equipment contaminated with alkali metals before recycling it. Decontamination is usually only a problem when the metals are used in their molten state. Some equipment may contain oxide, peroxide, or superoxide residue, which pose additional hazards and environmental aspects during the decontamination and disassembly process. This process shall have an IWS and may need to be addressed in an SP.
Below are general decontamination procedures. More detailed procedures can be found in Document 21.5, "Requirements for Transfer of Equipment and Property for Repair, Reuse, Maintenance, Storage, Excess, or Scrap," in the ES&H Manual.
Drain all alkali metal from the system.
Make sure the system has no cold spots that may cause residual metal to freeze or prevent low points from draining.
Compare the weight of the metal in the system to that removed, and account for any large loss before proceeding.
Purge the system with inert gas (do not use nitrogen for Li) and carefully dismantle the system. Look for residual metal or white, yellow, or orange discoloration that may be indicative of dangerous oxide or superoxide deposits. In cases where purging is desired, an SP shall be prepared. Do not use steam or alcohol to purge the system, except that a common and safe practice for NaK is to flush the system with isopropyl alcohol after draining the liquid NaK.
Small amounts can be disposed of as hazardous waste, larger amounts should be recycled or sold as scrap.
Reactivity series of metals : We have seen that some metals are more reactive than the others. In the chapter on Classification of Elements we have seen that the reactivity of elements decreases as we go from the left to right in the periodic table. Alkali metals from group 1 A such as Na, K, Cs are most reactive. Alkaline earth metals from group 2 A such as Mg, Ca are reactive but are less reactive than the alkali metals.
In the alkali group, as we go down the group we have elements Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). They have all only one electron in their outermost shells. All the elements show metallic properties and have valence +1. They give up electron easily. Reactivity or the ease with which these elements give off their electrons increases with the size of the atoms. The size of the atom increases from Li to Fr. The outermost electron is less loosely bound in Fr than in Li, as in Fr the distance between the last electron and the positive nucleus is large; this makes the attractive force binding or holding the electron to be less. Thus K will give up electron more easily than Na. This makes K more reactive than Na.
The alkaline earth group, as we go down the group we have elements Beryllium (Be), Magnesium(Mg), Calcium (Ca), Strontium (Sr), Barium (Ba) and Radium (Ra). They have two electrons in their last shell and their valence is +2 as they give up two electrons to form compounds. The elements in group II A are not as metallic as the alkali metals. Reactivity or the ease with which these elements give off their electrons increases with the size of the atoms. The size of the atom increases from Be to Ra. The outermost electron is less loosely bound in Ra than in Be, as in Ra the distance between the last electron and the positive nucleus is large; this makes the attractive force binding or holding the electron to be less. Thus Ca will give up electron more easily than Mg. This makes Ca more reactive than Mg.
The transition group elements such as Zn, Fe, Sn. Pb. Cu are also metallic and reactive. But the ease with which they loose electrons is less than that we see in alkali or alkaline earth metals.
The table below shows the reactivity series of metals. Hydrogen has been included in the table, although it is a non-metal. H is a special case because although it is a non-metal, it gives off an electron while forming bonds.
Metals which are more reactive than hydrogen are K, Na, Ca, Mg, Al, Zn, Fe, Sn and Pb. These metals can displace H from water or dilute acids and liberate hydrogen gas.
Metals which are less reactive than hydrogen are Cu, Hg, Ag. These metals do not replace H in a reaction with water or dilute acids.
From the reactivity series of metals shown in the above table we can say that :
metals that are more reactive than H are placed above H.
metals whose reactivity is less than that of H are placed below H.
The reactivity series gives an idea as to which element is capable of displacing other elements in a displacement reaction.
Definition
An alkali metal is any element other than hydrogen found in the first column of the periodic table. These elements include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium (Fr):
Do not confuse this term with the word alkaline which refers to a basic substance (one with a pH greater than 7) or with alkaline earth.
Additional Info
Francium is a radioactive element that is highly unstable. It occurs in such minute amounts that it will not be discussed further.
In their elemental forms, the alkali metals are all soft, ductile, malleable substances that can be easily cut with a knife or drawn into a wire. Although these are shiny when cut, they almost immediately tarnish in air.
Alkali metals are quite reactive towards air and water, with increasingly dangerous reactivity as one moves down the column from Li to Cs. The reaction with water can be summarized by the chemical equation below where M = an alkali metal.
2 M(s) + 2 H2O 2 M+(aq) + 2 HO-(aq) + H2(g)
Get your water-reactive signs and labels at Safety Emporium. The heat generated by this reaction is sufficient in most cases to ignite the hydrogen gas (H2) that is evolved in the reaction. This can result in a powerful explosion depending on the amount and surface area of the alkali metal. Elemental potassium and cesium are particularly dangerous in this regard; even one gram can cause a serious hazard. When working with alkali metals, be sure you have a fire extinguisher that is approved for Class D fires.
Because of their water-reactive and/or pyrophoric nature, alkali metals are usually stored under an inert atmosphere and/or mineral oil. This also reduces the rate of formation of dangerous peroxides. Note: lithium should not be stored under nitrogen because the two can react to form lithium nitride, Li3N.
Finally, note there is a great difference between an alkali metal and an alkali metal cation. For example, (elemental) sodium metal, Na, is quite dangerous to work with, whereas sodium chloride (which contains the sodium ion, Na+, and chloride ion, Cl-) is common table salt.
MSDS Relevance
Always use extreme caution when working with alkali metals. All equipment, solvents and chemicals need to be dry. Avoid contact with or storage near incompatible materials; for example, addition of sodium metal to carbon tetrachloride, other halogenated materials, or certain alcohols would lead to a catastrophic explosion.
Do not work with alkali metals unless you have had special training from someone who is experienced in working with these materials. Most accidents involving alkali metals tend to occur when one is cleaning up and "quenching" the alkali metal. Such procedures usually involve the use of flammable organic solvents, making such accidents quite severe. A proper Class D extinguisher should be available where alkali metals are utilized.
The lithium ion (Li+) is a psychoactive agent so avoid inhalation or ingestion of lithium-containing materials by using proper personal protective equipment such as dust masks, fume hoods, and gloves. See below for links concerning the use of lithium in treating manic depression (bipolar disorder).
Definition
Water reactive substances are dangerous when wet because they undergo a chemical reaction with water. This reaction may release a gas that is either flammable or presents a toxic health hazard. In addition, the heat generated when water contacts such materials is often enough for the item to spontaneously combust or explode.
In other words, water reactive materials are incompatible with water.
Get your water-reactive signs and labels at Safety Emporium.
Additional Info
Dangerous when wet materials are classified as R2 under the UN classification system and as Hazard Class 4.3 by DOT under 49 CFR. Special precautions, labeling and training are therefore required when transporting, storing and using such materials.
Examples of water-reactive chemicals include alkali metals, alkaline earth metals, anhydrides, certain carbides, hydrides, sodium hydrosulfite, and similar chemicals. An example of the chemical reaction of sodium metal with water is given below:
2 Na(s) + 2 H2O 2 Na+(aq) + 2 HO-(aq) + H2(g)
The heat generated by this reaction is sufficient in most cases to ignite the hydrogen gas (H2) that is evolved in the reaction. This can result in a powerful explosion depending on the amount and surface area of the alkali metal. Elemental potassium and cesium are particularly dangerous in this regard; even one gram can cause a serious hazard.
Another example of a dangerous when wet substance is aluminum phosphide which reacts with water to release highly toxic phosphine gas, PH3. This chemical reaction is commercially exploited to kill moles and related pests:
2 AlP(s) + 3 H2O Al2O3(s) + 2 PH3(g)
Thus, it is critical that water reactive substances be stored in dry areas and kept off the floor by the use of pallets or rack storage. Dangerous when wet materials should never be stored directly beneath active water sprinklers and should be isolated by a waterproof or water-resistant barrier (e.g., plastic sheeting or a water-tight secondary container) to protect the materials from water in the event the sprinkler system is activated elsewhere in the facility.
Likewise, these materials should be stored in the original shipping container or in a compatible container of equal or greater strength. Prior to storing reactive materials, all combustible rubbish, dry or oiled paper wrapping material, and other combustible materials should be removed from the storage area. The area should be conspicuously marked or posted to indicate the material being stored. Access to the reactive materials storage area should be restricted. Personnel should not be permitted to enter the area unless accompanied by an individual familiar with the hazards of the material stored in the area.
There are additional classes of reactive compounds under the UN and DOT classification schemes, such as pyrophoric substances. Therefore, further segregate such materials within your Reactive Storage area.
Finally, make sure that an appropriate Class D fire extinguisher is available in the event of an emergency and that personnel have been trained in the proper way to deal with fires involving water reactive materials. Water should not be used to fight fires that involve water-reactive materials.
Get your Class D extinguishers at Safety Emporium.
MSDS Relevance
Water-reactive materials pose serious risks. The MSDS will provide information about these risks as well as the precautions you should take in handling the material. Pay particular attention to the fire fighting media and procedures listed in the MSDS. Make sure that your water-reactive materials are well-marked so that fire fighters and other personnel are aware of the danger in an emergency situation and be sure to have a proper Class D fire extinguisher on hand.
Further Reading
The US DOT's Pipeline and Hazardous Materials Safety Administration has a Table of Water-Reactive materials Which Produce Toxic Gases (32 Kb PDF file).
Lawrence Berkeley National Lab has a good primer on Control Procedures for Reactive Chemicals that covers peroxides and water reactive chemicals.
The Alkali Earth Metals comprise the second column from the left. They are reactive metals that tend to oxidize in air. This makes it irritating to try to keep samples of them
Objectives
Students will
Identify basic properties of metals and the different types of metals.
Find alkali metals on the periodic table and review their key properties.
Discuss the use of alkali metals and other elements in the creation of fireworks.
Create a mural of fireworks, highlighting at least five metals used to make the different colors and effects.
Materials
Alkali Metals video
Periodic table
Large rolls of paper and markers to create murals
Index cards (five for each group of students)
Print and online resources about how fireworks are created
Computer with Internet access
Procedures
Have students name some common metals and write their names and atomic symbols on the board. For example, iron (Fe), copper (Cu), Silver (Ag), platinum (Pt), gold (Au). Ask students to predict the common properties of metals and make a list of their answers. Most metals are:
hard
shiny
solid at normal temperature (except Mercury)
good conductors of heat and electricity
malleable (can be flattened into sheets)
ductile (can be stretched into long wires)
Next, show students where metals are found on the periodic table. Point out that there are different types of metals, each with unique properties: alkali metals, alkaline-earth metals, transition metals, and other metals. Metals can be identified on the periodic table by the columns, or groups, in which they're found. At this point, you may want to review with students how the periodic table is organized:
The elements are arranged in order of atomic number, or number of protons.
Elements in the same row, or period, are made of atoms with the same number of electron shells.
Elements in the same column, or group, are made of atoms with the same number of electrons in their outer shell. They also share similar properties.
Find the Alakali Metals (group 1) on the periodic table. How many electrons do these elements have in their outermost shell? (one) What effect does this have on these elements? (They are inclined to lose their outer electron and therefore highly reactive.) Using what they learned in the video, ask students to list the key properties of alkali metals:
Soft
Tarnish readily
Low melting points
Low densities
Violently reactive
Explain that the alkali metal sodium was used to create the first explosive. Two Chinese alchemists accidentally discovered the explosive by mixing charcoal, sulfur, and saltpeter – a sodium compound. Before long, explosives were used to create the first fireworks. While today's fireworks are far more complex, they still rely on alkali metals and other elements to create different colors and effects.
Tell students that they are going to work in small groups to research the different elements used to create fireworks. Then they will create a mural of a fireworks display highlighting at least five metals used to make the different colors and effects. At least one metal should be an alkali metal. Give each group a large sheet of paper, markers, and five large index cards. On each index card, they should provide information for one metal used in their fireworks display. The card should be placed on their mural next to the appropriate firework and include the following information:
Element Name and Atomic Symbol: [Copper (Cu)]
Type of metal: [Transition Metal]
Use or Effect: [Creates blue fireworks]
Provide students with print and online resources about fireworks, such as the following websites. They may want to begin with the first two websites to learn about different fireworks shapes and effects. The other two websites provide information about different elements used to create fireworks.
Create Your Own Fireworks
http://www.fireworks.com/interactive/fireworks_show/default.asp
Starshell Glossary (Shapes of Fireworks)
http://www.firework.co.nz/fireworks/starshell_glossary.htm
Chemistry of Fireworks
http://www.fireworks.com/safety/chemistry-fireworks.asp
Pyrotechnics: It's Elemental
http://www.pbs.org/wgbh/nova/kaboom/elemental/
Once students have completed their murals, have each group present their fireworks display to the class
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Evaluation
Use the following three-point rubric to evaluate students' work during this lesson.
Three points: Students were active in class discussions; showed a strong understanding of metals, alkali metals, and the periodic table; developed a creative, attractive, and varied mural highlighting at least five metals; index cards identifying metals were accurate and complete.
Two points: Students participated in class discussions; showed a satisfactory understanding of metals, alkali metals, and the periodic table; developed an acceptable mural highlighting five metals; index cards identifying metals were mostly accurate and complete.
One point: Students did not participate in class discussions; showed a weak understanding of metals, alkali metals, and the periodic table; developed an complete or sloppy mural highlighting less than metals; index cards did not accurately identify metals or were incomplete.
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Vocabulary
alkali metal
Definition: A highly reactive metallic element belonging to group 1 of the periodic table, including: lithium, sodium, potassium, rubidium, cesium, and francium
Context: The alkali metals are as soft as cold butter and much less dense than most other metals.
element
Definition: A substance that is composed of one type of atom; an element cannot be chemically separated
Context: Sodium is the sixth most abundant element on Earth.
reactive
Definition: Taking part in a chemical reaction, as in an element
Context: Alkali metals are so reactive that they interact with most other elements they come into contact with.
valence electrons
Definition: The electrons in an atoms outermost electron shell that dictate how elements interact
Context: The single valence electron in the alkali metals makes them very unstable and they easily lose this electron to other elements.
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Academic Standards
Mid-continent Research for Education and Learning (McREL)
McREL's Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education addresses 14 content areas. To view the standards and benchmarks, visit http://www.mcrel.org/compendium/browse.asp.
This lesson plan addresses the following national standards:
Science-Physical Sciences: Understands the structure and properties of matte
National Academy of Sciences
The National Academy of Sciences provides guidelines for teaching science in grades K-12 to promote scientific literacy. To view the standards, visit this Web site:
http://books.nap.edu/html/nses/html/overview.html#content.
This lesson plan addresses the following national standards:
Physical Science
Science and Technology
The Alkali Metals are the metals in Group 1. They consist of Hydrogen,Lithium,Sodium, Rubidium,Cesium,and Francium. All the Alkali Metals have 1 electron in their outermost energy level. In order for the element to become stable, it has to give away one electron. Because the element lacks one electron, it loses a negative charge, that gives the element a positive charge.
Hydrogen
Hydrogen (1H) is the only gas at room temperature in the first group in the Periodic Table. It is a colorless gas and it is very reactive. It has 1 electron and mostly forms covalent bonds.
Hydrogen is the lightest element in the Periodic Table, it is also the most common element in the universe. The chemical symbol for Hydrogen is H.
Lithium
Lithium (3Li) is a solid that has a density of about half half as dense as water. Lithium is silvery at first but it tarnishes around a minute and becomes grey.
Lithium is used in batteries, greases, medicines, and glasses. Because Lithium is an Alkali Metal, it has one valance electron, or one electron in the outermost energy level. Lithium forms ionic bonds with Halogens and forms metallic bonds with other metals. The chemical symbol for Lithium is Li
Sodium
Sodium (11Na) is silvery white solid that has a melts at 370.87 K (degrees Kelvin). Sodium boils at 1156 K. NaCl is the normal table salt used in your cooking. Like all other Alkali Metals, Sodium has 1 electron in its outermost energy level. Sodium is less reactive than Lithium and Lithium, but it has more metallic properties than Lithium and Hydrogen. The activity of a metal decreases as it goes to the right of the Periodic Table. The properties of a metal increase as it goes down in the Periodic Table. The chemical symbol for Sodium is Na.
Potassium
Potassium (19K) is a solid at 298 K. Its appearance is silvery white and it makes up 1.5% by weight of the Earth's crust. Potassium is never found free in nature, but it can be obtained by electrolysis of the chloride or hydroxide. Apart from lithium, Potassium is the least dense known metal. It is soft and easily cut with a knife. It is silvery in appearance immediately after a fresh surface is exposed. It oxidises very rapidly in air and must be stored under argon or under a suitable mineral oil. As do all the other metals of the alkali group, it decomposes in water with the evolution of hydrogen. It usually catches fire during the reaction with water. Potassium and its salts impart a lilac colour to flames. The chemical symbol for Potassium is K.
Rubidium
Rubidium (37Rb) can be a liquid at ambient temperature, but only on a hot day given that its melting point is about 40°C. It is a soft, silvery-white metallic element of the Alkali Metals group (Group 1). It is one of the most most electropositive and alkaline elements. It ignites spontaneously in air and reacts violently with water, setting fire to the liberated hydrogen. As so with all the other Alkali Metals, it forms amalgams with mercury. It alloys with gold, caesium, sodium, and potassium. It colours a flame yellowish-violet. Like all other Alkali elements, it usually combines with halogens and is rarely found in nature. The chemical symbol for Rubidium is Rb.
Caesium
Caesium (55Cs) is spelled "Cesium" in the United States. Caesium is silvery gold and it is soft and ductile. It is the most electropositive and most alkaline element. Caesium, gallium, and mercury are the only three metals that are liquid at or around room temperature. Caesium reacts explosively with cold water, and reacts with ice at temperatures above -116°C. Caesium hydroxide is a strong base and attacks glass. The chemical symbol for Caesium/Cesium is Cs.
Francium
Francium (87Fr) is produced when actinium disintegrates. Francium is found in uranium minerals, and can be made artificially by bombarding thorium with protons. It is the most unstable of the first 101 elements. The longest lived isotope, Fr-223, a daughter of Ac-227, has a half-life of 22 minutes. This is the only isotope of francium occurring in nature, but at most there is only 20-30 g of the element present in the earth's crust at any one time. No weighable quantity of the element has been prepared or isolated. There are about 20 known isotopes in the Periodic Table. The chemical symbol for francium is Fr.
Control Procedures for Water Reactive Chemicals
Upon completion of this session, you will learn additional methods to protect yourself from the hazards of water reactive chemicals.
It should take you about 10 minutes to complete this training session. When you have read through the material, you will be asked to answer 5 questions.
The information presented in this section is a summary of the hazards and controls for these compounds. This is done for training purposes. However, if you wish to get more detailed information, please consult the CHSP.
Water reactive chemicals react violently with water releasing heat and in some cases explosive by-products. Of chief concern are the alkali metals. All alkali metals react vigorously with water to form the hydroxide. The rate of reaction increases as the atomic weight increases. Lithium reacts the slowest and poses the least hazard. The other metals react very quickly, generating great heat and splattering with the possible destruction of experimental apparatus. Hydrogen gas is also released in this reaction, and the heat generated from the reaction can ignite the hydrogen resulting in an explosion. A DOE document entitled "DOE-HDBK-1081-94, Primer on Spontaneous Heating and Pyrophoricity" provides further guidance.
Control Measures
Line managers shall identify and evaluate the use of water reactives in the work area to determine the extent of the hazard and to evaluate the controls necessary to safeguard employee health. MSDSs and other hazard databases for these materials should be reviewed and understood. AHDs maybe required for alkali metals. An EH&S Industrial Hygienist should be contacted to provide further guidance.
Substitution
If possible substitute a non-water reactive material for the one being used. Otherwise, procure and use the minimum amount required for the operation.
Engineering Controls
Alkali metals shall be handled in an inert atmosphere such as in a dry argon-filled glove box made of materials that are compatible with the metal. Nitrogen may be used except when handling lithium.
Work Practices
General traffic should be prohibited in areas where alkali metal operations are performed.
Avoid all skin and eye contact with the material. Where possible use tongs or appropriate tools to handle solids.
Oxidized materials (with a white surface coating) makes the material more hazardous to handle because the oxide can flake off. Note: Materials with a yellow or orange coating may indicate the presence of peroxides which may detonate if cut or abraded. Do not use these materials. They should be isolated and disposed of. Contact an EH&S Industrial Hygienis t for further guidance.
All tools used to handle alkali metals must be dry, rust-free, clean, and composed of a material compatible with the metal. Tools can be dried by baking in an oven, desiccating in a vacuum, or rubbing with anhydrous dry soda ash.
Assume that containers with alkali metals contain flammable hydrogen gas in the head space, even if stored under mineral oil or inert gas. Thus, no source of ignition shall be present where these containers are opened. Tools used to open the containers shall be of the spark less variety.
Personal Protective Equipment
The following is required when handling alkali metals:
Safety glasses with side shields
Laboratory coat (or equivalent)
Chrome leather gloves or appropriate chemical resistant gloves.
Closed toe shoes of leather construction
Where solid metal is handled without a barrier (e.g., glove box), a fire retardant apron and face shield or goggles are required. Additional personal protective equipment shall be stipulated in the AHD in cases where large quantities of solid alkali metals are in use.
Storage
Storage procedures and incompatibilities can be found in Storage Guidelines of the CHSP. General guidelines are presented below:
Separate alkali metals from incompatible chemicals. In addition to being water reactive, alkali metals also react with oxygen, acids, halogenated hydrocarbons and carbon dioxide). Consult the MSDS for specific storage guidelines.
Store all metals in the container provided by the manufacturer
Store alkali metals under mineral oil or in an inert atmosphere (note: Lithium reacts with nitrogen. Containers should be stored in a cool, dry environment, away from light and free from extremes of temperature and humidity).
Use secondary containment.
Emergency Procedures
Fire and Spill Emergency Preparedness
Anhydrous dry soda ash may be used for all metals except Lithium. Lith-X fire extinguishers must be used for Lithium. Alternative extinguishing agents such as powdered graphite or the commercial Met-L-X metal fire extinguishers may be used. Employees involved in metal work must be trained in the use of these extinguishing materials.
Only trained personnel shall attempt to control small, contained fires or spills. If fumes are escaping into the breathing zone of these personnel, no local employee shall attempt to extinguish the fire. Large or unconfined fires or spills, or fires where the ventilation system does not contain all of the fumes, shall be handled only by the Fire Operations (7-911).
Skin or Eye Contact
If any alkali metal fragment or drop enters the eye, it will immediately generate considerable heat which will likely result in severe eye damage. In such cases, the eyes shall be flushed with water from an eyewash/safety shower. Continue to flush the eye with water while someone dials 7-911 for emergency help.
When alkali metal comes in contact with the skin, the first response is to strip off all contaminated clothing. If contact with the metal occurs at only one or two spots on the skin, it is best to wash off those areas with mineral oil. A container with at least one quart of mineral oil shall be available in alkali metal work areas. If contact with the metal is widely distributed over the body, a decision on the best course of first aid must be made immediately. If the material is already burning, the victim should be drenched continually under a safety shower until emergency help arrives. If the material is not burning (perhaps sodium or Lithium scraps), the metal should be removed by wiping the skin with mineral oil. In all cases, dial 7- 911 for assistance.