Process of manufacture of phosphoric acid with recovery of co-products

Patent · Tue Jan 26 04:00:00 EST 1982

OSTI ID:5512244

Spigolon, S J; Wilson, E K

An improved process for the wet-acid process for manufacture of phosphoric acid with recovery of valuable co-products is provided. Phosphate rock is digested in a sulfuric acid/phosphoric acid mixture. Phosphoric acid is filtered from the digested rock, the gypsum thus formed, and sludge from the phosphoric acid, are second-stage acid treated, washed, and heated in a drier-calciner at 900/sup 0/ to 1300/sup 0/ C. Sulfur dioxide evolved from the gypsum and the fossil fuel is used to replenish the sulfuric acid. The hot impure lime remaining is fused in an electric furnace to form valuable calcium aluminum silicate products, which are then tapped, cooled, stored, and sold. The only waste products from the process are common, sulfur dioxide free combustion gases from the high sulfur content fossil fuel. Nearly 100% recovery of all phosphorus and fluorine values is claimed.

• Assignee: IFI; EDB-82-077536
• Patent Number(s): US 4312842
• OSTI ID: 5512244
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320305* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Industrial Waste Management
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
BY-PRODUCTS
CALCIUM COMPOUNDS
CALCIUM SULFATES
CHALCOGENIDES
DIGESTION
GYPSUM
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MINERALS
OXIDES
OXYGEN COMPOUNDS
PHOSPHATE ROCKS
PHOSPHORIC ACID
PRODUCTION
RECOVERY
ROCKS
SEDIMENTARY ROCKS
SEPARATION PROCESSES
SILICATES
SILICON COMPOUNDS
SULFATE MINTERALS
SULFATES
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
SULFURIC ACID