SU814850A1 - Method of phosphoric acid production - Google Patents

Description

These differences can improve filtration performance up to 1100-1770 kg / m.h.

With the consumption of calcium sulphate half-citrate less than 15%, the filtration capacity is low: 780-840 kg / m, h with consumption O is 10%, with consumption greater than 80%, the filtration capacity does not increase and the sediment to be separated during filtration has a setting property. The OD hour is the minimum required al shift of the two forms of calcium sulfate crystalline hydrate. With more than 6 hours of stirring, the reaction volume is noticeably increased. In the selected temperature range, a high dissolution rate of calcium sulfate hemihydrate is achieved.

Improving the performance of filtrating occurs due to the hydration of calcium sulfate injected in the hemihydrate and deposition of particles of gypsum formed on the surface of gypsum present in the reaction pulp, and also due to the formation of large aggregates of calcium sulfate.

Example. 100 kg of apatite concentrate (39.4%) for 4-6 hours with 100.1 kg of sulfuric acid (92.0%) and 290 kg of recycled filtrate (19.6% P, 2, O) are treated. Then, to 480 kg of the resulting suspension of gypsum about phosphoric acid, 24 kg of calcium sulfate hemihydrate is added and the mass is kept for 0.1 hour at. 504 kg of the suspension is fed to a vacuum filter, where 127 kg of production phosphoric acid (30%) and wet sediment are separated, which is subjected to countercurrent washing of 193 kg of hot water. This forms 290 kg of circulating filtrate (19.7%), which is returned to the decomposition stage, and 28.0 kg of sediment with a total moisture content of 44.8%. Since the filtration capacity reaches 1200 (dry sediment), the process requires 0.158 m of filtering surface. Removal of production phosphoric acid is 240 kg of 1m filtering surface per hour.

Example 2. 100 kg of apatite concentrate (39.4%) for 4-6 hours at 70 ° C are treated with 1OO, 1 kg of sulfuric acid. (92.0%) and 29O kg of recycled filtrate (19.6% P O- ). Then, to 480 kg of the resulting suspension of gypsum in phosphoric acid, add pot 4O kg of calcium sulfate hemihydrate and maintain the mass for 1 hour at. 520 kg of the suspension is fed to a vacuum filter, where they are separated

127 kg of production phosphoric acid (30.2% RjOy) and a wet sediment, which is subjected to countercurrent washing of 193 kg of hot water. This forms 290 kg of recycled filtrate (19.7%

Ruhr, which is returned to the decomposition stage, and 296 kg of sediment with a total moisture content of 44.0%. Since the filtration capacity reaches 1770 (dry draft), the process requires 0.117 m of filtering surface. The removal of production phosphoric acid is 523 kg of 1 m of filtering surface per hour.

Example 3. 1OO kg of apatite concentrate (39.4%) for 4-6 hours at 70 ° C are treated with 10O, 1 kg of sulfuric acid (92, O%, 30.8 kg of the first filtrate (32, 2%)

and 259.2 kg of the second filtrate (18.2% PdOx-). Then, 484 kg of the formed gypsum suspension are added with 384 kg of a suspension of calcium hemihydrate in phosphoric acid (34% of PdOr containing 53.3% of the solid phase, and the mass is maintained for 6 hours at 85 ° C, after which 857 kg of the suspension is fed to a vacuum filter, where 35 O kg of liquid (} yse (32.2%) is separated, of which 120.5 kg is released as production acid, 30.6 kg is returned to the decomposition stage and 200 kg is sent to the preparation of a suspension of calcium sulfate hemihydrate in phosphoric acid. The amount of washed gypsum, with a total moisture content of 36.2%, is 359 kg. So a filtration productivity reaches 11OO kg (dry pellet), then to perform the process desired surface 0.262 m. Sh productional phosphoric kis lots is 254 kg.

Claims (2)

The invention of the method of producing phosphoric acid by treating the phosphate raw materials with sulfuric and circulating phosphoric acids, the crystallization of gypsum, the introduction into the reaction slurry before filtering the sulfate hemihydrate, followed by filtration and by washing the precipitate characterized by heme, in order to increase the filtration efficiency, calcium sulfate hemihydrate is introduced in the amount of 15-80% 5814850 & by weight of gypsum and the resulting pulp1. B. Kopylov. Technologists extract when mixed with 0.1-phosphoric acid. L., Himi 6 hours at 72-85 P.1972, p. 163-179. Information sources, 2. Akts. for vk uk taken into account in the examinationN) 1328357 Cl, C 1A, 30.08.73.