SU1643512A1 - Method of concentration of high-carbonate phosphorites - Google Patents

Abstract

The invention relates to a technology of mineral fertilizers and can be used to enrich highly carbonated phosphates containing more than 14% C0 "and contributes to an increase in the content of phosphoric anhydride in phosphate. According to the invention, which includes the treatment of phosphorite with 55-57% nitric acid, diluting the reaction mixture with wash water, filtering, washing and drying the product, the washing water is pre-mixed with nitric acid, taken in an amount calculated by the following formula: 1С 63 С4И2К / 28 Cg / 71 C3), where Mf is the mass of nitric acid, kg; C is the concentration of nitric acid,%; Mg is the mass of phosphate, kg; C2 - the content of PgOg- in phosphate,%; C b - the content of C0g in phosphate,%; С $ - CaO content in phosphate,%; K is an empirical coefficient varying from 0.83 to 0.93. 1 hp f-ly, 1 tab.

Description

This invention relates to the chemistry and technology of mineral fertilizers and can be used to enrich highly carbonated phosphates containing more than 14% CO.

The purpose of the invention is to increase the content of phosphoric anhydride in phosphate.

A finely ground phosphorite is used with a sieve residue with a cell size of 0.16x0.16 mm 1%, containing,%: Р205 18.5; CaO 45.6; C0g 14.4.

Example 1. 1.0 kg of water returned from the washing stage and 0.932 kg of 57.00% nitric acid (K 0.93) were introduced into the stirred reactor without heating, then for 60 minutes at equal time intervals 20

/

portions were injected with 1.0 kg of phosphorite and continued mixing for 60 minutes. Then the suspension is filtered on a Buchner funnel, the solid phase is washed with 1.0 kg of water and dried at 100-110 ° C to constant weight. You get 0.614 kg of phosphate concentrate and 1,669 kg of the spent solution containing 6.9% of Ni and 1.1%. The spent solution in a known manner is processed into nitrogen-phosphorus fertilizer. The wash water is returned to the dilution of nitric acid in the next enrichment cycle.

Example 2. The procedure for performing the method is the same as in Example 1, but the empirical coefficient K is 0.88, and

the duration of the introduction of phosphate to acid 45 minutes

Example 3. B, a reactor with an agitator without heating was introduced with 1.0 kg of water returned from the washing stage and 0.832 kg of 57.00% nitric acid (K 0.83), then for 30 minutes with equal time intervals of 20 portions enter 1.0 kg of phosphorite and continue mixing for 60 minutes. Then the suspension is filtered on a Buchner funnel, the solid phase is washed with 1.0 kg of water and dried at 100-110 ° C to constant weight. You get 0.700 kg of phosphate concentrate and 1, 538 kg of the spent solution containing 6.6% N and 3%. The spent solution is processed in a known manner to a nitrogen-phosphorus fertilizer. The wash water is returned to the dilution of nitric acid in the next enrichment cycle.

When the phosphorite is injected into the solution for less than 30 minutes, the yield of Pg.0 to the phosphate concentrate decreases, and for longer than 60 minutes, there is no increase in the output to the phosphate-concentrate.

The number of portions into which phosphorite is divided does not have a significant effect on the composition of the final products, but the larger the number of portions, the smaller the size of each portion and, consequently, the smaller the amount of emitted carbon dioxide and foam formed when a separate portion is added to the acid. Therefore, for a more uniform process, it is advisable to introduce phosphorite in as many batches as possible. Since the actual enrichment process is not ideal, the empirical coefficient K is introduced into the formula for calculating the consumption rate of nitric acid. For a value of K over 0.93, the yield in the Phosphoconcentrate is significantly reduced, and for K less than 0.83 the content in phosphate concentrate decreases . In the particular case, if phosphorite contains 18.5% P205, 45.6% CaO and 14.4% CO, then the consumption of nitric acid according to the proposed formula is 15-30% more than the known one. With a different composition of phosphate there will be another according to Honieihie; since, unlike the prototype, the consumption of nitric acid in the proposed method depends not only on the content of CO in phosphate, but also

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the same and the content of Cao and. A higher rate of consumption of nitric acid at a higher yield of P205 B phosphoconcentrate causes an increase in the content of PgP and a decrease in the ratio of CaO: P Og- in phosphoconcentration compared to the prototype,

PRI me R 4. The method is performed by a known method.

The main indicators of the process are shown in the table.

As can be seen from the data presented in the table, the proposed method allows to increase the phosphate content by 7.0-7.7%, without worsening other characteristics of the enrichment process.

Claims (2)

1. A method of enriching high-carbonated phosphorites, including treating the phosphorite with 55–5.7% nitric acid using wash water, filtering, washing with the formation of wash water and drying the product, characterized in that, in order to increase the content of phosphoric anhydride in phosphate, washing water is pre-mixed with a nitrogen acid taken in the amount calculated by the formula jf M 63 C M2K / 28 C (1 + 44 Cg / 71 C,) where M. is the mass of nitric acid, kg; Cj is the concentration of nitric acid,%; Mg is the mass of phosphate, kg; С - PdO content in phosphorus-TP 7 1 b, o, С- - С0 content in phosphorus those / j; С l - CaO content in PHOSPHOR-7 those / o, K - empirical coefficient, varying within 0.83-0.93, with the subsequent introduction into the resulting solution of highly carbonated phosphorites in equal portions for 30-60 minutes with equal time intervals with stirring until the reaction ceases. 2. A method according to claim 1, characterized in that 0.832-0.932 kg of nitric acid is added to 1 kg of water. Rio content,%: in the initial phosphate 18, 5 in phosphoconcentrate 26.2 Absolute increase % 7.7 CaO content in phosphoconcentrate,% 37.7 CaO: Р20 ratio 1,4 in phosphoconcentrate C0g content in phosphoconcentrate,% 2.6 Output 2®5 in Ф ° СФ ° concentrate,% 87.0