SU947149A1 - Process for producing complex fertilizer - Google Patents

Description

(5) METHOD OF OBTAINING A COMPLEX FERTILIZER

one

This invention relates to a technique for producing complex fertilizer by the nitric-sulfuric acid processing of high ferrous natural phosphates.

Known process for the preparation of compound fertilizer type NPK by mixing phosphate with nitric acid and circulating a mixture of nitric and phosphoric acid, followed by reaction azotnofosfornokislotnoy drawing with sulfuric acid, separating calcium sulphate, filtering and processing of the resulting solution (a mixture of nitric and phosphoric acids) in the fertilizer, ammoniation by packing, adding potassium salt and drying p J.

However, in this case it is possible to use phosphate raw materials, in which the ratio Fe-0 does not exceed 1: 12-15.

The use of raw materials containing up to U – T Fe2.0i} does not allow the process of obtaining a complex fertilizer by the nitric acid method due to the transition of ferrous iron to solution, and then to fertilizer in the form of water-insoluble compounds.

The closest to the proposed technical essence and the achieved result is a method of obtaining complex fertilizer, including the decomposition of phosphate raw materials with nitric acid and circulating solution, treatment of the resulting pulp with sulfuric acid, separation of gypsum, separation of the resulting solution into working and production in a ratio of 1.6- l, ammonization of the production solution

15 to pH 5-7, brew, mix with potassium salt and dry.

 By this method, high-iron phosphates are processed. At the same time, 25-31 jelly20, which is in the raw material, passes into the liquid phase. The nitrophosphoric acid pulp thus obtained is treated with sulfuric acid and the calcium sulfate is separated by filtration. The solution, which is a mixture of nitric and phosphoric acids, is divided into two streams. A part is used as a circulating solution for recycling to the decomposition stage, and the production part containing all the nitric acid introduced into the process and phosphoric acid extracted from the phosphate raw material is withdrawn as a semi-product. This part of the solution is ammoniated, the suspension is evaporated, mixed with potassium salt and dried with T2j. The disadvantages of this method include the low content of water-soluble soluble phosphates in the fertilizer (70-72%) and severe conditions of evaporation of the suspension due to the presence of a solid phase (phosphates of sesquioxides, calcium ftrid), which causes evaporation of equipment. The degree of use of the evaporator equipment does not exceed 70. The aim of the invention is to improve the quality of the fertilizer by increasing the content of water-soluble phosphate in it and increasing the degree of use of the evaporator equipment. This goal is achieved by that in the process of obtaining complex fertilizers, including the decomposition of phosphate raw materials with nitric acid and recycled solution, the processing of the obtained pulp with sulfuric acid, the separation of hygiene, the separation of the obtained solution is working and production in the ratio 1, 7-1, the ammonization of the production solution to pH-5-7, packing, mixing with potassium salt and drying, ammotization of the production solution is carried out. first, to a pH of 3.0-4.5, the resulting suspension is thickened, the condensed portion with an impurity of 40-60 is separated and returned to the decomposition stage, and the remaining clarified portion is pre-ammoniated. Partial ammonization of the production solution allows precipitation of impurities of sesquioxides to be precipitated. When the pH of the solution is 3.0-4.5, these impurities are released most completely and, on return, as a condensed pulp, are co-precipitated into the head of the process along with calcium sulfate. The moisture content of the thickened pulp 40-60% is determined by the fact that, at a value of 40%, the displacement time increases significantly, which reduces the performance of the circuit. When the humidity is above 60%, the pulp transportation 9 9 is difficult and productivity also decreases due to the return of a large amount of liquid phase. Separating the admixture of sesquioxides from the production solution allows increasing the content of the water-soluble form in the fertilizer and reducing the incrustation of the sediment on the walls of the evaporation equipment. Example 1. As a raw material, phosphorite of the Tsko-Kamskoe deposit calcined at SOSSR is used, wt .: 2.5; CaO 39.7; 3.3; A1.0, 1.8; but. 18.4. 100 kg of phosphorite are treated with 8 kg of 50% nitric acid in the presence of 300 kg of working solution and 20 kg of sediment. The pulp in the amount of 50A kg is treated with 6k, 6 kg of sulfuric acid (93) and filtered, the precipitate is washed with 10D kg of water and in the amount of 190.6 kg (including 10.6 kg of iron phosphates 7 are dumped into the blade. Kg of filtrate is divided into two Flow: 300 kg are sent to the phosphate decomposition stage as a circulating solution, and 12 kg of ammonia (pH 4.5) are ammoniated with 178 kg of the production solution. The ammonium suspension (190 kg) is concentrated to a light transmittance of 0.7 (humidity 40) and 20 kg of sediment is directed to the decomposition stage, and 170 kg of the solution is pre-monted 5 kg of ammonia and evaporation With removal of 15 kg of water, 1bO kg of evaporated pulp is mixed with 40 kg of KCC and after drying with removal of 35 kg of water, 1b5 kg of nitroammophoshka is obtained.The content of water-soluble phosphates is 90 instead of lQ-12% by a known method. 80% instead of 70% by a known method. Example 2. 100 kg of phosphorite are treated with 84 kg of HNO in the presence of 300 kg of working solution and 16 kg of sediment. Pulp in the amount of 500 kg is treated with 64.6 kg of sulfuric acid and filtered. The precipitate is washed with 10 kg of water and in the amount of 186.6 kg (including 9.0 kg of iron phosphates) is dumped. kg of filtrate is divided into two streams: 300 kg is sent to the phosphate decomposition stage as a circulating solution, and 178 kg of the production solution are ammoniated 10.8 kg of ammonia (pH 3.0). Ammoniated suspension (188.8 kg) thicken

to a light transmittance of 0.95 (humidity 60) and 16 kg of sediment are sent to the decomposition stage, and 172.8 kg of the solution are ammoniated with 6.2 kg of ammonia and evaporated to remove 15 kg of water. (Kg of one stripped off pulp is mixed with 40 kg of KCC and after removal of 39 kg of water, 165 kg of nitroammofoski are obtained. The ratio,) RF Od ....... is E instead of 70-72

J-VTCB

According to a known method. The degree of use of evaporation equipment is 83 instead of 70% according to the known method.

Example 3. 100 kg of phosphorite are treated with 8 kg of HNO, in the presence of 300 kg of working solution and 18 kg of sediment. The pulp in the amount of 502 kg is treated with b, 6 kg of sulfuric acid and filtered. The precipitate is washed with 100 kg of water and in the amount of 188.6 kg (including 9.8 kg of iron phosphates) is dumped. kg of filtrate is divided into two streams: 300 kg is sent to the phosphate decomposition stage as a circulating solution, and 178 kg of the production solution are ammoniated 11, kg of ammonia (pH) Ammonized suspension (189, t kg is condensed to a light transmittance of 0.9 (moisture content 5b%) and 18 kg of sediment are sent to the decomposition stage, and Ul, kg of the solution are monitored 5.6 kg of ammonia and evaporated to remove 15 kg of water. 1b2 kg of evaporated slurry is mixed with AO kg of KC6 and after removal of 37 kg of water, 1b5 is obtained kg nitroammofoski. Attitude

  is 97 instead of 70-72% by a known method. The degree of utilization of evaporation equipment is 85% instead of 70% by a known method.

The use of the invention allows in comparison with the known 20-25% increase in the content of water-soluble form in the fertilizer. At the same time, the degree of use of evaporation equipment is increased by 110-15%.

ten

Claims (2)

1.Phosphorite processing Kzrat .., Himi, 1975, p. I6t-2l6. -. 2. Trudy NIUIF. 22V, 1973, p. 130-132.