SU1198044A1 - Method of producing ammophos - Google Patents

Abstract

D the remainder of the acid. 2. The method according to claim 1, about tl and h.yash and so that the resulting suspension is separated by condensation and the clarified portion is ammoniated. (/) WITH

Description

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This invention relates to the production of mineral fertilizers on the basis of extraction phosphoric acid.

The purpose of the invention is to increase the content in the fertilizer of an assimilable form of nitrogen.

Example 1. Phosphoric (1026 g) acid is divided into two parts. One part of 923 g (90% of the total volume) is treated with stirring (70 ° C) for 3 h h 62 g of the starting phosphate raw material. The resulting suspension, containing in the liquid phase,%: 20.4, 0.37 SO, is stirred for 3 minutes with the remaining 103 g (10% of the total) of the acid and the resulting pulp is separated by condensation. A precipitate of 234.9 g with a ratio of T; L equal to 1: 1.8 is directed to extinction. The clarified product of 852.8 g, containing,%: 20.0 0.38 0.87 Ca, is ammoniated to a pH of 4.5, mixed with a previously prepared retur and dried. The resulting ammophos contains,%: 53, cu., 10.7 N.

Example 2. Phosphoric acid (995 g) is divided into two parts. One part (398 g or 40%) is treated with stirring () for 3 h 60 g of the starting phosphate raw material, the sample, suspension, -. The liquid in the liquid phase,%: 23.4 0.56 30, is stirred for 3 minutes with the remaining part (597 g or 60%) of the acid, and the resulting pulp is separated by crushing. The precipitate (200 g) with a T: W ratio of 1: 1.5 is directed to the improvement of the precipitation. The clarified product (866 g) containing,%: 19, 1.6 SO and 0.4 is ammoniated to a pH of 4-, 5, mixed with a previously prepared retur and dried.

The resulting ammophos contains:% 53.3 RZ0 uev ,, 11,6 nitrogen.

The table shows the effect of the ratio of phosphoric acid fluxes (on treatment with phosphate raw materials and on mixing) on the content of PyOf in nitrogen, and nitrogen in ammophos

From the results of Table 1, it can be seen that a decrease in the proportion of acid entering the treatment with ferrous phosphate, less than 40% of the total flow, as well as an increase of more than 90%, leads to a decrease in the amount of P-Oy in the fertilizer.

A distinctive feature of the proposed method is that fos44: 2

The fororic acid is divided into two parts and the treatment with natural phosphate is first subjected to 40-90% of the total acid flow, followed by mixing the resulting suspension with the remaining acid.

The proposed preparation of the desired product in two steps is based on data from the study of the solubility of dicalcium phosphate in phosphorus-containing solutions. With a two-step supply of calcium-containing agent in a phosphorus-containing solution, the majority of the solid phase precipitates with an excess of phosphate ions in the form of dicalcium phosphate, which has a coarser structure than the mixture of dicalcium phosphate and tricalcium phosphate,

by a known method. When the remaining amount of calcium-containing reagent is added, the additional amount of CaNRO does not crystallize in the solution, but on the precipitate that has already formed, resulting in an additional increase in its individual crystals. As a result, the precipitate has better filtering properties than that obtained by the known method.

The yield, in the finished product according to the proposed method, is increased compared with lime due to the more complete binding of the PgO solution to dicalcium phosphate. As a result, with the same CaO: P O- mass ratio, according to the proposed method, almost all phosphates are precipitated from the initial solution, while, according to the known method, the amount of calcium-containing reagent to be injected is not enough for complete binding, since

along with dicalcium phosphate, tricalcium phosphate also precipitates. Due to this, in the proposed method, the output 2 finished product is higher by 7-9%,.

The increase in nitrogen content is due to the fact that as a result of the interaction of moncalcium phosphate with sulphate nonons, mixing operations produce poorly soluble calcium sulphate and additional free phosphoric acid in comparison with the prototype, which leads to an increase in nitrogen content following 119808044.

The result of the formation of the content of the mono- and diammonium phosphate. Pg forms from the nitrogen at the stage of the product amonization product is

Using the proposed savings of 6-8 thousand rubles. on

Note:% must be equal to II.

Claims (2)

1. METHOD FOR PRODUCING AMMOPHOS, comprising treating the starting phosphoric acid with calcium phosphate and ammonizing the resulting suspension, characterized in that, in order to increase the content of digestible forcemeat ^Β ₂ θ5 and nitrogen in the fertilizer, 40-90% acid is treated with calcium phosphate and the resulting suspension is mixed with the remainder of the acid. 2. The method according to claim 1, with thinner in that the resulting suspension is separated by thickening and the clarified part is ammoniated. S ω> 1 I