Fluorogypsum waste solidification material
OwnerDavid G. Azarinventor
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Abstract
A process, and the product produced thereby, for the preparation of a waste solidification material from hardened fluorogypsum as a by-product of the manufacture of hydrofluoric acid by reacting fluorospar with sulfuric acid, removing hydrogen fluoride from the reaction product, slurrying the by-product with water, placing the slurried by-product fluorogypsum in settlement ponds until the fluorogypsum hardens, the hardened fluorogypsum having a pH of greater than about 5 to about 13, including heating the hardened fluorogypsum to evaporate substantially all water physically mixed with the fluorogypsum and further heating the fluorogypsum to reduce the water chemically bound to calcium sulfate in the fluorogypsum to form about 0.5% to about 9% by weight.
Claims19
A process for the preparation of a waste solidification material from hardened fluorogypsum having a pH of greater than about 5 to about 13 produced as a by-product of the manufacture of hydrofluric acid by reacting fluorspar with sulfuric acid, removing hydrogen fluoride from the reaction product, slurrying the by-product in settlement ponds until the by-product fluorogypsum hardens, comprising:
- a. heating said hardened fluorogypsum having a pH of greater than about 5 to about 13 for a time sufficient to evaporate substantially all water physically mixed with said hardened fluorogypsum, and
- b. further heating said hardened fluorogypsum at a temperature above 105.degree. F. for a time sufficient to reduce water chemically bound to calcium sulfate in said hardened fluorogypsum to from about 0.5% to about 9% by weight.
A material suitable for use as a waste solidification material comprising:
- a. substantially dry, hardened, particulate fluorogypsum containing, in combination, about 99% by weight calcium sulfate anhydrite and calcium sulfate having water chemically bound to said calcium sulfate, said water chemically bound to said calcium sulfate being present in an amount of from about 11/2% to about 9% by weight.
- b. said waste solidification material having a particle size range of from about 5000 microns to about 37 microns, and
- c. said material having a pH of from greater than about 5 to about 13.
A process for the preparation of a waste solidification material from hardened fluorogypsum having a pH of from greater than about 3 to about 13 produced as a by-product of the manufacture of hydrofluoric acid by reacting fluorspar with sulfuric acid, removing hydrogen fluoride from the reaction product, slurrying the by-product in settlement pond until the by-product fluorogypsum hardens, said hardened fluorogypsum having a pH of from greater than about 3 to about 13, comprising heating said fluorogypsum in a rotating furnace at a temperature above 105.degree. F. for a time sufficient to reduce water chemically bound to calcium sulfate in said hardened fluorogypsum to from about 0.5% to about 9% by weight.
Dependencies are inferred from the claim text.