SU889647A1 - Method of processing phosphate raw material - Google Patents

Description

(54) METHOD FOR PROCESSING PHOSPHATE RAW MATERIALS

one

The invention relates to a process for the processing of phosphate raw materials using nitric acid and can be used in the manufacture of mineral fertilizers.

There is a method of processing phosphate raw materials with nitric acid by mixing the pulp with a solution of ammonium sulfate, precipitating calcium sulfate and separating the precipitate.

However, this method allows to obtain only unbalanced: NP-fertilizers.

The closest to the proposed technical essence and the achieved result is a method of processing phosphate raw materials by decomposing the latter with nitric acid by 40-60% with subsequent decomposition of the remaining part of the phosphate raw material with sulfuric acid when ammonium sulfate solution is introduced into the pulp.

calcium, filtering it and washing 2.

The disadvantage of this method is that this results in a significant release of nitrogen oxides (5-10% of the nitric acid added).

The purpose of the invention is to reduce the release of nitrogen oxides.

The goal is achieved

According to the method of processing phosphate raw materials by decomposing the latter with nitric acid by 40-60% and then decomposing the remaining part of the sulfate ion containing 5 solutions, a mixture of sulfate and ammonium bisulfate is used as the sulfate-calcium sulfate was used It is filtered and washed.

20 The solution is processed into a balanced fertilizer.

Claims (2)

The difference of the method is that as the sulfate-ion-containing solutions use the mixture at a ratio of 1: 3.5-8 in the amount of 1, parts by weight. recyclable phosphate. It is possible to use the mixture as a mixture; incomplete conversion of ammonium sulfate to ammonium bisulfate. The range of the ratio of ammonium sulfate and ammonium bisulfate in the mixture is due to the following. With a decrease in the ratio of less than 1: 3.5, the decomposition of phosphate is incomplete, and with an increase of more than 1: 8, the separation of nitrogen oxides from 0.5-0.7% increases to 1% of the nitric acid added. When reducing the amount of the mixture is less than 1.2 weight.h. on 1 weight. of the processed phosphate, tzkzhe, incomplete decomposition of phosphate occurs, and with an increase in the specified amount of more than 2 parts by weight. the composition of the fertilizer is not justifiably changed. Example .100 g of apatite lags for 1 h 150 g of nitric acid with a concentration of 50%. The resulting pulp is fed to the second reactor and mixed with 234 g of the solution, co. holding 35.91% NH4HS04 and 10.3% (NH,) nSO i. The pulp is stirred for 1 h, filtered and washed with hot water taken in the amount of 137.t. Wash water is used for a solution of 104.8 g of ammonium sulphate converted to 80% of ammonium 277 g of mother liquor, neutralize 13 g of ammonia and receive 290 g of pulp, which is processed to nitrophos. The result is 170.5 g of fertilizer with a ratio of NfPel :. The amount of nitrogen oxides leached from exhaust gases is 0.75 g. Example 2.100 g of apatite is spent for 30 minutes 115.4 g of nitric acid with a concentration of 65%. The resulting slurry is fed to the second reactor and mixed with 398 g of 1 solution containing 30% NH HS04H 3.29% (NN4) 5.5 The pulp is stirred for 2 hours, filtered and washed with hot water taken in an amount of 283 g. Wash water is used to dissolve ammonium sulphate converted to 90%. 387 g of the mother liquor neutralize 14.68 g of ammonia and get 402 g of pulp, which is processed to nitrophos. As a result, 238.7 g of fertilizer is obtained with a ratio. The amount of oxides released from the exhaust gases is 0.15 g. Example 3. 100 g of Kovdorsky apatite decompose for 30 minutes 135.68 g of nitric acid with a concentration of 47%. The resulting slurry is fed to the second reactor and mixed with 282 g of solution prepared by dissolving 105.6 g of a mixture of NH4HSO and (NN4) 504 in 176.5 g of wash water. The pulp is stirred for 1.5 hours, filtered and washed with 176.5 g of hot water. Calcium sulfate is fed to the solution by conversion of ammonium carbonate to ammonium sulfate. The mother liquor is neutralized with 8.7 g of ammonia and the pulp is processed into fertilizer. As a result, 153.2 g of fertilizer grade 20:24 are obtained with a MgO content of 2.3%. The amount of nitrogen oxides leached from exhaust gases is 0.5 g. Using the proposed method allows to significantly reduce the emission of nitrogen oxides (from 5-10 to 0.5-0.7% of the nitric acid added). In addition, the method allows to significantly reduce the consumption of scarce sulfuric acid, replacing it with a cheaper product. Claim 1. Method for processing phosphate raw material by decomposing the latter with nitric acid by 40-60% followed by decomposition of the remaining part of the phosphate raw material with sulphate-containing solutions, precipitating calcium sulphate, filtering it and washing it, characterized in that, in order to reduce the reduction of nitrogen oxides , a mixture of ammonium sulfate and ammonium bisulfate with a ratio of 1: 3.5–8 in the amount of 1.2–2 parts by weight is used as the sulfate ion of the durable solution. on 1 weight. recyclable phosphate. 2. The method according to p. 1, about tl and .4 a ki p and with the fact that as a combination of 589647-4 si take the product incomplete conversion .1. Patent of Germany No. 1961020, ammonium sulfate in ammonium bisulfate. cl. 16 a 11/00 (C 05 B 11/00), 1971 Sources of information, 2. US patent number 4036624, taken into account in the examination of cl. 423-319, 1977,