Method for preparing sodium nitrate by using nitric acid to decompose phosphorus ore byproduct calcium nitrate

A technology of sodium nitrate and calcium nitrate, which is applied in the field of calcium nitrate, can solve the problems of no patent application and no sodium nitrate, and achieve good economic and environmental benefits

Inactive Publication Date: 2008-05-28
GUIZHOU RES INST OF CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

So far, there is no process report on manufacturing sodium nitrate with nitrophospha

Method used

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  • Method for preparing sodium nitrate by using nitric acid to decompose phosphorus ore byproduct calcium nitrate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0020] Embodiment: adopt the present invention to produce sodium nitrate with nitric acid decomposition phosphate rock by-product calcium nitrate:

[0021] first step metathesis

[0022] The composition of the by-product calcium nitrate obtained through freezing is as follows:

[0023] Element

P 2 o 5

CaO

MgO

F

N

Content / % No.1

1.62

21.99

0.12

6.03

number 2

1.65

19.7

0.13

5.36

[0024] number 3

0.31

22.22

0.56

0.22

12.44

No 4

0.79

22.54

1.36

0.21

10.89

[0025] Mix calcium nitrate with the gypsum filter residue washing liquid in the subsequent process and the returned sodium nitrate mother liquor, then add it to the metathesis tank, add sodium sulfate under stirring, carry out metathesis at 50°C~60°C, and react for 1~2h; then filter the reaction product , filter out the dihydrate g...

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PUM

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Abstract

The invention discloses a sodium nitrate preparation method by calcium nitrate that discomposes byproduct of phosphate rock by using nitric acid. The sodium nitrate preparation method comprises that: (1) double decomposition: namely, calcium nitrate, washing liquid of gypsum filter residue in post procedure and returned mother liquor of calcium nitrate are mixed and stirringly added with sodium sulfate to double discompose, and then the generated dihydrate gypsum is filtered and washed by clean water, the lotion is recycled; the generated calcium nitrate is left in the filtrate; (2) removing calcium through purification: namely, limestone powder and soda are added to the filtrate in the last step to neutralize and heated to boil and then the mixture is filtered to remove calcium carbonate which is dried to obtain fertilizer-grade calcium hydrogen phosphate; (3) evaporation, crystallization and separation: namely, the neutralized filtrate in the last step is put into a double evaporator to condense and cooled to crystallize, thus obtaining sodium nitrite magma. The sodium nitrite magma is put into a centrifugal separator to separate to obtain sodium nitrite product. The preparation method of the invention can transform the waste residue calcium nitrate that is discharged from a nitric phosphate device by freezing method into sodium nitrite product, which has good economic and environmental benefit.

Description

technical field [0001] The present invention relates to calcium nitrate, also relates to the sodium nitrate prepared by double decomposition of calcium salt, specifically, belongs to the method for producing sodium nitrate by decomposing calcium nitrate by-product of phosphate rock with nitric acid. Background technique [0002] It is a well-known technology to decompose phosphate rock with nitric acid and produce nitrophosphate fertilizer by freezing method or mixed acid method. ) In this paper, the production status of nitrophosphate fertilizer is introduced, and the technological characteristics of freezing method and mixed acid method are analyzed. The so-called freezing method is a method of separating excess calcium in the crystal form of calcium nitrate tetrahydrate from the nitric acid decomposition solution of phosphate rock by freezing crystallization. As a by-product, calcium nitrate has not been used much, so it is mostly used as fertilizer or converted into amm...

Claims

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Application Information

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IPC IPC(8): C01D9/12C05B3/00
Inventor 顾春光
Owner GUIZHOU RES INST OF CHEM IND
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