SU893983A1 - Method of producing fertilizer - Google Patents

Description

(54) METHOD OF OBTAINING FERTILIZER

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This invention relates to a method for producing fertilizer containing phosphorus and nitrogen, which is widely used in agriculture.

A known method of producing fertilizer is by mixing phosphate with a mixture of sulfuric acid and ammonium sulfate at a ratio of 3: 1 and subsequent calcination at 350-500 ° C HP.

However, this method requires a large consumption of sulfuric acid.

Closest to the proposed technical essence and the achieved result is another well-known method of producing fertilizer, including mixing phosphate with ammonium sulfate and calcining the mixture at 350-500 ° C. In this case, ammonium sulfate is taken in the amount of 140-190% of the stoichiometric norm for calcium oxide ZJ.

The disadvantage of this method is the production of a product with a low content of digestible form (8.8-9.8%), as well as the complexity of the process due to the need for thorough mixing of the dry components.

The purpose of the invention is to increase the available form in the product and simplify the process.

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The goal is achieved by the fact that phosphorite is mixed with ammonium sulphate solution with a concentration of 25-70%, the resulting suspension is dried at an exhaust temperature of 90–200 s to a moisture content of 0.1–10% and then calcined at ZZO-ZOO C.

The appropriateness of the chosen conditions is determined as follows.

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Claims (2)

When working with an ammonium sulfate solution with a concentration of less than 25%, a large amount of moisture will be removed, which is not economically feasible; when working with an ammonium sulfate solution with a concentration of more than 70%, an uneven mixing of reagents occurs and the product has a variable composition. When drying the suspension at the temperature of the exhaust gases below, the process proceeds very slowly and it is possible that the suspension will not dry out; at the temperature of the exhaust gases, the ammonium sulfate partially decomposes. When the suspension is dried to a moisture content of more than 10%, the material becomes hardly transportable, and drying the suspension to a moisture content of less than 0.1% also leads to a significant decomposition of ammonium oulphate. Example 1. 1 ton of phosphorite, for example, the Kingisepp deposit, is mixed with ammonium sulphate solution with a concentration of 25% (100% of the stoichiometric rate) and 5, tons of suspension are obtained, which are dried at a temperature of 200% waste gases to a content of 0.1%. The semi-products in the amount of 2.05 tons are calcined for 2 hours and 2.00 products are obtained with a content of 12.2%% 05 C Example 2. 1t of phosphate is mixed with an ammonium sulfate solution with a concentration of 70% (140% of the stoichiometric standard) and 2.48 suspensions are obtained, which are dried at a flue gas temperature of 90 ° C to a moisture content of 10%. Semi-products in the amount of 2.23 tons are calcined for 1 hour and 1.9 products are obtained with a content of 12, Ch.5X. Example 3. 1 ton of phosphate is mixed with ammonium sulfate solution 34 at a concentration of 50% (120% of the stekiometric standard) and receive 2.07 tons of suspension, which is dried at a temperature of exhaust gases to a moisture content of 5%. An intermediate product in the amount of 2.09 tons is calcined for 1.5 hours and 1.63 tons of product are obtained with a content of 16.0% 16, 0% P OS Use of the proposed method allows to obtain a product with an Ilj rvce content of 12.2-16%, greatly simplify the node cm Reagent solutions, liquidate mills for grinding ammonium sulphate. In addition, the proposed method allows this type of fertilizer to be obtained from low-quality phosphorites. Claims of Invention A method of producing a fertilizer comprising mixing phosphate with ammonium sulfate followed by calcining the mixture at 350-500 0, characterized in that, in order to increase the digestible form P (0 in the product and simplify the process, ammonium sulfate is introduced as a solution by concentration 25-7.0%, the resulting suspension is dried at a flue gas temperature of 90-200 C to a moisture content of 0.1-10%. Sources of information taken into account in the examination 1.My.Dykanbayev, A.Tikhonov V. Khimi and technology of mineral fertilizers and natural salts, t. X, Alma-Ata, 1964, 175, 2. Patent of the GDR No. 7413, Cl05V 1/02 1954 (prototype).