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1751981 
Journal Article 
A Nontoxic Substitute for Hazardous Heavy Liquids Aqueous Sodium Polytungstate (3Na2WO4.9WO3.H20) Solution (Note) 
Gregory, MR; Johnston, KA 
1987 
1 
New Zealand Journal of Geology and Geophysics
ISSN: 0028-8306 
NIOSH/00179313 
30 
3 
317-320 
The use of aqueous solutions of sodium-polytungstate (3Na2WO4.9WO3.H20) (SPT) of varying densities as a nontoxic substitute for the hazardous halogenated hydrocarbons, tetrabromoethane (79276) (TBE) and bromoform (75252) which are used in geological laboratories for the separation of light and heavy minerals was described. An SPT solution with a density between 2.96 and 3.06 was produced by dissolving 1 kilogram of the salt in 250 milliliters of distilled water. The density was lowered by adding distilled water or was raised, to a maximum of 3.1, by evaporation at room temperature or by very gentle heating. Separation of heavy and light minerals in a set of representative sand samples was performed with both SPT and TBE. Both fractions were washed in distilled water and allowed to dry overnight on the filter paper at room temperature. There were no significant differences in recovery rates for either the light or heavy fractions between TBE and SPT. SPT was much more viscous than TBE, so that filtering rates with SPT were quite slow. The samples wetted more easily with SPT and hence did not aggregate or raft to the extent that is common with TBE. The authors conclude that SPT is safe to use, creates no storage or handling problems, does not discolor in sunlight, does not require absolutely dry samples, and has low toxicity, and that these advantages outweigh the lower cost and lower viscosity advantages of the haloalkanes. 
DCN-167139; Brominated hydrocarbons; Tungsten compounds; Alkanes; Halogenated hydrocarbons; Bromoalkanes; Minerals; Filtration; Toxic materials; Laboratory techniques