Plastic and nonmetallic article shaping or treating: processes – Explosive or propellant article shaping or treating – Forming or treating particulate material
Patent
1991-02-06
1993-06-29
Nelson, Peter A.
Plastic and nonmetallic article shaping or treating: processes
Explosive or propellant article shaping or treating
Forming or treating particulate material
149 35, C06B 2100
Patent
active
052231844
ABSTRACT:
Multiple processes and apparatuses for improving the prior system of making gas generant pellets or tablets made of sodium azide, molybdenum disulfide and sulfur wherein powdered ingredients thereof are slurried in water, subjected to wet grinding, spray dried to a powdered material which is molded into pellets or tablets which find use in vehicle crash bags or inflators.
The first improvement to the old process and apparatus involves adjusting the basicity of the water to a pH of greater than 8.0 up to about 12.5 via the addition of sodium hydroxide, followed by the addition of sulfur and molybdenum disulfide and finally the sodium azide whereby azide addition is made to a basic mixture of the other ingredients thereby keeping hydrazoic acid concentration levels below about 3.times.10EXP(-3) moles per liter.
The second improvement to the old process and apparatus involves (1) softening the water before its use in slurrying the powdered ingredients to remove undesirable Ca and Mg ions and/or (2) adding sodium sulfide and/or tri-sodium phosphate to the slurry to precipitate any remaining undesirable Ca, Mg, Pb, Fe, Mn and Cu ions as non-hazardous compounds. Each of these metal ions is reduced to no more than about 25 ppm or less.
Also these two improvements are joined together to form a system wherein even better safety results occur.
The improvements not only extend to the final product produced, but to the intermediates at the slurry stage as well as at the spray dried stage, which products differ due to significant elimination or minimization of hydrazoic acid and other contaminant metal ion species above mentioned.
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W. Lorch, Handbook of Water Purification, 1987, pp. 84-95, Ellis Horwood Ltd., Chichester, England.
Olsen Ritchie
Smith Gary L.
Taylor Robert D.
Morton International Inc.
Nelson Peter A.
Rutledge L. Dewayne
White Gerald K.
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