SU1392063A1 - Method of concentrating phosphorus-containing ores - Google Patents

Abstract

This invention relates to a process for the enrichment of naturally-difficult phosphorous-containing ores used in the chemical industry for the production of fertilizers. The aim of the invention is to increase the efficiency of the process by increasing the recovery rate in phosphates. The method is carried out by treating phosphorus-containing ores with a complex-forming compound, in which 10-20% solution of urea is used, the treatment is carried out at a ratio of T: W 1: 10-20, temperature and pH 0.25-0, 75, the separated liquid phase is heated to 95-105 ° C and the double calcium phosphate salt with urea is separated. The method allows to increase the degree of PjOj recovery in phosphates from 31-32 to 51- 78%. 1 hp f-ly, 2 tab. I (G

Description

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This invention relates to a process for the enrichment of naturally occurring phosphorous-containing ores used in chemical industry and in the manufacture of fertilizers.

The purpose of the invention is to increase the efficiency of the process by increasing the degree of change. in phosphates.

Example. 50 g of phosphate ore from the Karatau deposit containing 23j44 PjOj is processed with 500 ml of a 15% urea solution for 90 min at a ratio T; Ж 1; 15, -jg pH 0.5 and 40 С, Then the separation is made liquid phase from solid. The solid phase is recycled at the content, the liquid phase is heated to 100 ° C, and 20.71 g of a double calcium phosphate salt with urea containing% is separated; 24.5; (NH) CO 25e71. The filtrate, containing 69 g (NB4), 2.CO, is returned to the process. The isolated double salt of calcium phosphate with urea is subjected to reextraction with 100 ml of water, at. 10.3 g of a phosphate concentrate containing 44.3% are obtained, and 100 ml of filtrateJ containing 5 g of carbamide, E: NOV, is used in the process.

Other examples of specific implementations of the method are presented in Table 1.

Use as a complexing compound of carbamide with a concentration of 10–20% at a ratio of (10–20), 20–50 ° C and a pH of 0.25– 0.75, heating the liquid phase after separation at 95–105 ° C, isolation of a double salt Calcium phosphate with carbamide, which is then subjected to re-extraction with water at 20-25 ° C, provides an increase in the recovery rate from 31-32 to 51-78%.

In tab. 2 shows the effect of water temperature during reextraction on the content of PdO in phosphate concentrate

25

thirty

35

40

45

The data table. 1 and 2 show that the best degree of extraction was achieved with the enrichment of hard-to-process phosphorus-containing ores with urea with a concentration of 10–20% at a ratio j (10–20), at 20–50 ° C and a pH of 0.25–0.75, and heating the liquid phases at 95-105 C, the release of calcium phosphate double salt with urea with

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-jg 20632

its subsequent reextraction at a water temperature of 20-25 C.

When the urea concentration is less than 10%, the recovery rate decreases, at a concentration of more than 20%, the recovery rate does not change, but the urea consumption increases.

The increase in temperature above 50 ° C results in the reverse precipitation of the dissolved double salt of CaHPQ, n (NH) 2 CO, and a decrease in temperature below 20 ° C worsens the solubility of urea and the degree of extraction from phosphate ore.

With a decrease in T: W of less than 1:10, the pH is less than 0.25, and also with an increase in T: W of more than 1:20 and a pH of more than 0.75, the degree of extraction from the phosphate ore decreases.

water temperature for more than 25 ° C

When the liquid phase is heated at a temperature greater than urea, it decomposes and the filtrate cannot be reused, i.e. the loss of urea increases, and when heated to less than 95 ° C, the recovery rate decreases.

Increasing the stripping time results in the re-precipitation of urea, and lowering the water temperature below 20 ° C is undesirable, as additional cooling equipment is required.

Urea, as a complexing agent, differs from known similar compounds, for example, ethylenediaminetetraacetic acid (EDTA), in that it exhibits selectivity for phosphate ions in the presence of sulfate nitrate and / or carbonite ions, as well as iron and aluminum. This allows carbamide to be used for the selective extraction of phosphates from phosphorous ores in the presence of these substances, giving complex compounds with EDTA, In addition, the COCNH complex, P CaHP04, soluble in water up to 60 ° C, precipitates up to 100 ° C in solution. facilitating the release of nitrogen-phosphate fertilizer from mixtures of water-soluble salts.

The proposed method allows increasing the recovery of phosphates from 31-32 to 51-78% and using the resulting double salt as an effective fertilizer.

Claims (1)

1. A method of enrichment of phosphorus-containing ores, including their treatment with a complexing compound, separating the liquid phase from the solid phase, followed by the release of phosphates, characterized in that use 10-20% solution of urea, while the processing is carried out at the ratio (10-20), temperature 20-50 ° C and pH 0.25-0.75, and the separated liquid phase is heated to 95-105 ° C with the release of the double salt of calcium phosphate with urea. 2, the method according to p. 1, difference the aim of increasing the efficiency of the process is that with the fact that the By increasing the degree of calcium salt of calcium phosphate from PjOj clumps in phosphates, as a bamide, they are subjected to re-extraction with water. complexing compound 20-25 sec. . T "vlits" 1 ; Table 2