SU779364A1 - Method of producing complex fertilizers from phosphate ores - Google Patents

Description

(54) METHOD FOR OBTAINING COMPLEX Y; CONVENTIONS FROM PHOSPHATE ORES

The invention relates to methods for producing complex fertilizers from phosphate ores and can be used in the direct chemical processing of poor 5 phosphate raw materials.

A method of producing complex fertilizers is known, using for the decomposition of nitric acid phosphate a concentration of 10-50% in the presence of a gas, containing oxides of nitrogen, at 90 ° C (Y)

However, this method is indiscriminate. The decomposition solution used to produce fertilizer contains a large amount of compounds of iron and aluminum, which impair the quality of the fertilizer.

The closest in technical essence and the achieved result is a method of obtaining complex fertilizers, which consists in the decomposition of 2d phosphate with a diluted nitric acid concentration of 1.0-6.0%, with and the ratio T: W in pulp 1: 10-25. The resulting nitrogen-phosphoric acid extract is separated from the insoluble residue and neutralized with ammonia, then the nitro-receptive precipitate is filtered off, dried and granulated 23.

However, when phosphate is decomposed, harmful impurities, JQ

oxides of iron and aluminum, reducing the selectivity of the process and impair the quality of the final product. The resulting complex fertilizer contains a large amount of calcium ions, which dilute the finished product, reducing its quality and reducing the nutrient content.

The purpose of the invention is to increase the selectivity of phosphorus extraction and the removal of calcium ions while simultaneously increasing the nutrient content of the fertilizer.

. The goal is achieved by the fact that decomposition is carried out with a diluted nitric acid concentration of 1.06, 0% in the presence of dilute sulfuric with a concentration of 1.5-2.0%, taken from the calculation of the ratio of CaO: P ... g in a solution equal to 0.7-0.9.

The optimization of the parameters of the method is carried out by the COP effi- ciency of selectivity (Kg) and by the ratio of CaOgR O in solution, in accordance with the data presented in the table.

An increase in the concentration of sulfuric acid of more than 2.0% leads to a decrease in the selectivity of the extraction of phosphorus and

reduction of nutrients in the fertilizer.

Example. 200 g of phosphate ore from the Verkhnekamskoye deposit is placed in a 2.5 liter reactor, 2.0 l of a nitrogen-sulfuric acid solvent containing 3% HNO and 1.7% H is poured ((and mixed for 10 minutes. The pulp is filtered, the filtrate and the slurry analyze. Extraction to solution,%: P, 05.99.8; Fe, 4.02; A% 0, j 2.15, Kg 16.2. CaOtPQ Og 0.81 ratio. Then the filtrate is neutralized with ammonia to pH 6. , 3, the resulting pulp is filtered. The complex fertilizer is dried and granulated. The filtrate and the fertilizer are analyzed. The results are presented in the table.

Content in fertilizer,%:, 43.7; ., 31.4, and also N 8.2. AT

phosphate and calcium filtrate not detected. Сцц (} 3%; Т: Ж 1:10; t 18 ° С.

13.8 0.94

3,862.04

3,982.12. 15.2 0.90 15.7 0.85

4,002,13 16,2 0,81

4,022,15

16.00,785

4,052.19

15.60,74

4,152,25

15.10.70 4.292.31

13.70,67

4,672,61

This method of obtaining complex fertilizers from phosphate ores allows selective processing (selectivity increases by 70-80% compared with the known method) iron and aluminum-containing phosphate ores into nitrogen-phosphorus fertilizers with a high content of nutrient vest (39-46% and N 6-10%).

Claims (2)

1. US patent 3669641, cl. 23-165, 15.05.70. 2. Authors certificate of the USSR. 35 598855, cl. C 05 V 11/06, 04/20/76 (prototype).