SU842020A1 - Method of phosphoric acid production - Google Patents

Description

(54) METHOD FOR OBTAINING PHOSPHORIC ACID

This invention relates to a process for the production of phosphoric acid used for the production of phosphate fertilizers.

The known method of phosphoric acid golucine is carried out by pretreatment of phosphate raw materials with phosphoric acid with K9 concentration of PjOf3O-5O% at 9O120С for 2-15 minutes, followed by decomposition of sulfuric acid, crystallization and separation of calcium sulfate l.

There is also known a method for producing phosphoric acid with a concentration of 15–18% P Oy at 30–30 ° C for 5–2 O min, followed by decomposition with sulfuric acid. The decomposition is carried out at 9O-12O C for 3 u,

A disadvantage of the known methods is the low degree of decomposition (no more than 96%). In addition, raw materials with a low content of sesquioxides can be processed by known methods with PjOy less than

Oh, O8. With a higher content of sesquioxides, their content in production acid increases.

The purpose of the invention is to increase the degree of decomposition and enable the processing of phosphate raw materials with respect to. RjO,: more than O, O8.

The goal is achieved by the fact that in the process of obtaining phosphoric acid by pretreatment of phosphate raw materials containing one-and-a-half metal oxides with circulating phosphoric acid with a concentration of 12-2 O% P Oj followed by decomposition of sulfuric acid and the resulting calcium sulfate decomposition of sulfuric sourum is carried out at 40 ° -6 ° C for 2-5 minutes.

as a result, the degree of decomposition increases to 99.2%, and raw materials with a PjO ratio greater than 0.08 can be processed.

Claims (2)

At a temperature below and the interaction time of menbe 2 minutes, the degree of decomposition decreases, and at a temperature above 6 ° C / time and more than 5 minutes, the content of solid oxides in the product increases. Example. 1OO g of phosphate rock of the Telex deposit (composition, wt,% PjO, - 13.7; CaO -2O, 6; fe.C) - ,, 5.2 Ab2C)} 6 | 47 | MpO 1.7, insoluble residue (43.5%) is treated for 2 minutes at 6 ° C in a 13O5 g stirred reactor with a circulating phosphoric acid solution with a concentration of 2 O% P Oy. Then gradually over 2 minutes, the introduction of 36.8 g of 98% sulfuric acid, i.e. 1OO% stoichiometric amount of CaO phosphate ore samples, and kept at the same temperature for another 2 minutes. The resulting suspension is separated by centrifuging, followed by washing the precipitate with water. 64.4 g of production acid is obtained with a concentration of 2O, 8% Pg Oy with the content of sesquioxides, wt% FejO, O, 05 | AejOj 0.3 and 1O8 g of phosphogypsum composition, wt.%: Ca O 16.9; rej, Oj4,2; 2.3; Pj .O, 36 | jPjOj 609-0,28. The yield of Pj Os in phosphogypsum acid is 99.2%. PRI me R 2. SO of g of phosphate rock of the Telek deposit, the composition specified in Example 1, processes for 5 minutes at 40 ° C in a stirred reactor 187 5 g of a solution of circulating phosphoric acid with a PgOj content of 12%. Then, 36.8 g of 98% sulfuric acid was gradually introduced over 3 minutes. The resulting suspension is held at the same temperature for 3 more minutes and separated in a centrifuge with subsequent 04 washing of the precipitate with water. After separation of the phases, 1O6.3 g of production acid is obtained with the concentration of PgOfl2.6% with the content of sesquioxides, wt%: Fep, 0.028; AtgOj 0.22 and 114.2 g of phosphogypsum, wt% 1 CaO 17.1; , 4.5; А {2Оэ 2.05, .О, ЗО, О, О36. The yield of Pj Oj- to phospho-gypsum acid is 97.8%. Thus, the proposed method allows to increase the degree of phosphate decomposition and to process phosphate ores with a low O content without prior enrichment. The method of obtaining phosphoric acid by treating phosphate raw materials containing one-and-a-half metal oxides with circulating phosphoric acid with a concentration of РЗ 05 12-2О% with subsequent decomposition with sulfuric acid at elevated temperatures and separation of the resulting calcium sulphate precipitate. This is due to the fact that, with the aim of increasing the degree of decomposition and providing the possibility of processing the raw material with a ratio of more than 0.08 without increasing the content of sesquioxides () product, decomposition with sulfuric acid is carried out at a temperature of 40 ° -6 ° C for 2-5 minutes. Sources of information taken into account in the examination 1. The author's certificate of the USSR. No. 477942, cl. From 01 to 25/22, 1975. 2. USSR author's certificate number 51393O, cl. From 01 to 25 / 22,1976.