Calcium hydroxide​, monohydrate → HCID 131713080, compound

HRID 1995054Notes

Reaction equation

HRID 1995054 reaction equation
[O-:1][P:2]([O-:5])([O-:4])=[O:3].[O-:6][P:7]([O-:10])([O-:9])=[O:8].[O-:11][P:12]([O-:15])([O-:14])=[O:13].[F-:16].[Ca+2:17].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[OH-].[Ca+2].[OH-].O>O>[OH2:1].[O-:8][P:7]([O-:10])([O-:9])=[O:6].[O-:13][P:12]([O-:15])([O-:14])=[O:11].[O-:3][P:2]([O-:5])([O-:4])=[O:1].[F-:16].[Ca+2:17].[Ca+2:17].[Ca+2:17].[Ca+2:17].[Ca+2:17]

Participants

4

Reactant 2

HCID 5289063Calcium hydroxide​, monohydrateHCID 10207414Fluorapatite (Ca5F(PO4)3)3×

Product 1

HCID 131713080HCID 131713080, compound

Reagents, catalysts & solvents 1

HCID 962WaterSolvent5×

Procedure

Having reference to the specific embodiment presented schematically in FIG. 1, 268 gallons per minute of acid waste water having a pH of approximately 1.8 is contacted in spiral classifier 12 with 200 tons per hour of raw phosphate rock having a particle size distribution as shown in Table III. The raw phosphate rock feed from conveyor 10 has approximately 12% water and 88% solids. A counter-flow of 44 tons (176 GPM) of acid waste water having less than about 1% solids, overflows the wier of spiral classifier 12 into line 6. The partially neutralized waste water in line 6, having a pH of about 2.3, is conveyed to line 4 where it and the unground phosphate rock of 2.3 pH discharged from the spiral classifier 12 are further neutralized using approximately 0.83 tons of lime per hour (103 pounds per 1000 gallons of acid waste water) as milk of lime from line 5 to yield neutralized waste water-phosphate rock mixture having a pH of about 6. The neutralized waste water and raw phosphate rock from spiral classifier are fed by line 4 to the grinding mill 14 at a joint feed rate to achieve a liquid-solids ratio necessary to form a ground phosphate rock slurry of 68% solids from the grinding mill 14. The ground phosphate rock slurry at a pH of 6 is then conveyed from the holding tank to a conventional attack tank or digestor 30 for contacting of the slurry with sulfuric acid to form a product slurry of phosphoric acid and crystalline hydrated calcium sulfate.

Sources & evidence

ORD record
ord-29d0f45e188840ee8dbd87b11f2bd70a
Source dataset
uspto-grants-1983_09
Patent number
US04402923

Reaction notes

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