SU1456394A1 - Method of processing fluorophosphate slurry - Google Patents

Abstract

The invention relates to methods for processing production wastes, in particular, to methods for processing fluorophosphate fluids formed during the neutralization of wastewater from the production of phosphate fertilizers. The purpose of the invention is to simplify the process while reducing energy consumption and reagent consumption. In the method of processing fluorophosphate sludge, including its treatment with ammonium sulphate solution containing free sulfuric acid, the subsequent separation of the solid and liquid phases, neutralization of the sparing phase and subsequent processing of the resulting suspension, the liquid phase is neutralized with a solution of calcium hydroxide to pH 5-7, the precipitate is filtered , and the filtrate is returned to the processing of the original fluorophosphate sludge. Neutralization of the liquid phase with calcium hydroxide solution is carried out for 15-20 minutes. 1 hp f-ly, 2 tab. "C ate

Description

one

The invention relates to methods for processing production wastes, in particular to methods for processing fluorine-phosphate spams generated by neutralizing wastewater from the production of phosphate fertilizers.

The purpose of the invention is to simplify the process while reducing energy consumption and reagent consumption.

Example 1.20g of oshama neutralization of wastewater containing 32% R., J, 17.4% (calculated on the dry matter) is mixed with 200 g of ammonium sulphate solution containing 20% by weight (, 1-, 5% by weight The resulting suspension is stirred for 60 minutes at which the precipitate formed is then filtered, the filtrate is neutralized with a 10% calcium hydroxide solution to a pH of 6 for 20 minutes, the precipitate formed is filtered off and dried at 10.0 ° C. The dried product contains 40.1% , 0.3% F.

The remaining examples are made analogously to example 1, but with different final pH values and duration of the neutralization process and their results are summarized in Table. one.

Neutralization of the liquid phase with a solution of calcium hydroxide in the proposed pH range of 5-7 results in the formation of water-insoluble two- or three-substituted calcium phosphates, which precipitate and are separated by filtration. At the same time, ammonium sulfate remains in the filtrate and can be reused for

four:

cl

about

00

with

four

1456394

machining fluorophosphate helmets, or as an end product. As a result of carrying out the process according to the proposed method, the processing of sludge is greatly simplified, the consumption of reagents is reduced by returning ammonium sulphate back into the cycle and replacing expensive ammonia with neutralization with a non-deficient and cheap reagent. The advantages of this method include the formation of concentrated phosphate fertilizer containing up to 40%.

Conducting neutralization to pH values below 5 results in insufficient complete precipitation from the liquid phase. The implementation of neutralization to pH values of 7 leads to the formation of more basic phosphates, i.e. an increase in the CaO / P O ratio and, moreover, leads to an excess consumption of calcium hydroxide due to the formation of calcium sulfate.

According to the proposed method, the replacement of ammonia with calcium hydroxide provides for obtaining a concentrated phosphate fertilizer containing up to 40%. This is due to the fact that the fertilizer obtained by a known method is a mixture of sulphate (N114). MH, HP04 ammonium. P content

/.30 phosphate

Cay (P04) jOHj, which is accompanied by an increase in the liquid phase of H and ions, i.e. a decrease in the degree of neutralization. Thus, a neutralization time of 15-30 minutes is essential to the process.

After carrying out the neutralization process, the system under consideration can be presented in the form of a suspension containing СНРО и) in solid i. (III) 280 in the liquid phase. In the absence of a filtration stage when parsing this suspension, according to

By a known method, a mixture (NH) S04 is formed; Caj (PO), CaHPO, contained in | (Ballast quality 50, which does not allow to obtain concentrated fertilizer. In addition, it does not reach 20 seconds to simplify the process due to the presence of energy-intensive and technologically more complex curing stage. When filtering the neutralized suspension. the product is a mixture of CaNRO and Cae (PO4) 2, and the liquid phase, which is an aqueous solution of ammonium sulphate, is returned to Shch1KL. Thus, the replacement of the stage of evaporation with a filtration stage makes the process easier and more concentrated. go by product.

In tab. 2 shows the comparative data of the known method and the preamble is 2.35-4.90% containing.

nitrogen nitrogen is 20–21%, and the rest comes

The amount of sulfur that is ball is. The proposed method of processing

The feline and anti-fluorophosphate spam provide

concentrated fertilizer. Fertilizer-a significant simplification of the process, the lower, obtained by the proposed use of ammonium sulphate

Sob is a mixture of CaHRO and

Sa, (ROLE) oh, i.e.

4 1

does not contain in its

and ammonia, as well as obtaining as the final product a concentrated phosphate fertilizer containing up to 40%.

content in the product

composition of sulfur, due to which it succeeds

to raise

up to 40%

When the neutralization time is less than 15 minutes (established experimentally), the neutralization reaction is incomplete, up to 15-20% remains in the liquid phase and is lost. An increase in the duration of a neutralization period of more than 30 minutes does not lead to an increase in the degree of neutralization, therefore, it is not advisable. In addition, with an increase in the neutralization time (more than 30 minutes), the formed di- and tri-substituted calcium phosphates are hydrolyzed to more basic compounds such as hydroxyapatite.

Cay (P04) jOHj, which is accompanied by an increase in the liquid phase of H and ions, i.e. a decrease in the degree of neutralization. Thus, a neutralization time of 15-30 minutes is essential to the process.

After carrying out the neutralization process, the system under consideration can be represented in the form of a suspension containing СHRO i) in solid i. (III) 280 in the liquid phase. In the absence of a filtration stage when parsing this suspension, according to

a known method produces a mixture (NH) S04; Caj (PO), CaHPO, contained in | (Ballast quality 50, which does not allow to obtain a concentrated fertilizer. In addition, the process is not simplified due to the energy-intensive and technologically more complicated stage of evaporation. When filtering the neutralized suspension. is a mixture of CaNRO and Sae (PO4) 2, and the liquid phase, which is an aqueous solution of ammonium sulphate, is returned to Shch1KL. Thus, the replacement of the stage of evaporation by the filtration stage makes the process easier and more concentrated. product.

In tab. 2 shows the comparative data of the known method and proposed.

and ammonia, as well as obtaining as the final product a concentrated phosphate fertilizer containing up to 40%.

45

Formulas

the invention

1. The method of processing fluorophosphate shcham, including its processing

gjj with ammonium sulphate solution containing free sulfuric acid, the subsequent separation of the solid and liquid phases, neutralization of the liquid phase and the subsequent processing of the obtained peng suspension, characterized in that, in order to simplify the process while reducing energy consumption and consumption of reagents, the liquid phase is neutralized with a solution hydroxide

514563946

calcium to pH 5-7, the precipitate filter-2. The method according to claim 1, is distinguished, and the filtrate is returned to the dog and the fact that neutralizing the starting fluorophosphate-liquid phase with a solution of calcium hydroxide

pshama

Qi is carried out for 15-30 minutes.

1A563948

table 2

PjOy content in fertilizer, May. %

Fuel consumption and energy2, 35-4.90

4.37 467

26.2

(ammonia water brand B)

Ammonium sulfate consumption,%

100

 Consumption in terms of 1 ton of product. According to factory data.

38.7-41.2

360 not consumed

16,1

(technical lime according to GOST 9179-77)

Not consumed

Claims (2)

Claim Method of processing fluorophosphate sludge, including its treatment with a solution of ammonium sulfate containing free sulfuric acid, subsequent separation of solid and liquid phases, neutralization of the liquid phase and subsequent processing of the resulting suspension, characterized in that, in order to simplify the process while reducing energy and reagent consumption , the liquid phase is neutralized with a solution of calcium hydroxide until pH 5-7 is removed, and the sludge is recovered. 5 1456394, the precipitate is filtered off returning to the initial fluorophosphate 2. The method according to π. 1, characterized in that the neutralization of the liquid phase with a solution of calcium hydroxide is carried out for 15-30 minutes Table 1 I Example The mass ratio of sludge: solution Concentration (ΝΗ ₊ ) _Δ 5Ο ₄ , wt.% Temperature ° C Processing time, min Concentration of H _t so ₄ , May. % PH neutralization 1 ' 1:10 20 60 60 1,5 5 2 1:10 40  55 60 s oh 6 3 1: 4 20 60 60 6.0 7 4 1:10 20 60 45 3.0 6.5 5 1:10 40 55 60 3.0 ⁸ 6 1:10 40 55 60 3.0 4 7 1:10 40 55 60 3.0 7 8 1:10 40 55 - 60 3.0 7 Famous 1:10 40 55 60 3.0 6 Continuation of the table; 1 Example Neutralization time, min The content of components,% The content of P-10 5 in the filtrate after neutralization,% The degree of extraction of P10 5 from the sludge, ’% F remaining in the sediment.,% RdO-g F 1 \ 20 40.1 0.51 300 91.3 96.5 2 fifteen 41.2 0.68 120 . 93.7 90.1 3 zo 38.7 0.41 80 91.2 86.0 4  25 40.8 0.91 100 93.6 89.5 5 20 35.0 0.71 80 93.7 90.1 6 20 ' 29.8 0.69 3000 93.7 90.1 7 10 36,2 0.79 1900 93.7 90.1 8 40 40.3 0.50 100 93.7 90.1 Famous ' - ² L 0.20 - 93.7 90.1 table 2 Method Parameters Indicators by the method famous j proposed The content of PjOy in fertilizer, May.% Fuel and energy consumption *, including: steam, G-cal electric power, kWh The cost of 1 ton of neutralizing reagent, rub Ammonium sulfate consumption,% 2.35-4.90 38.7-41.2 4.37 ** Not consumed 467 ** 360 ** 26.2 (brand B ammonia water) 16.1 (technical lime in accordance with GOST 9179-77) 100 Not consumed * Consumption in terms of 1 ton of product ^ ** According to factory data.