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Method for producing sodium metabisulfite or sodium sulphite by using gypsum as raw material

A technology of sodium pyrosulfite and sodium sulfite, which is applied in the preparation of alkali metal sulfite, etc., can solve the problems of insufficient production of sodium pyrosulfite, sulfur, pyrite resources, loss of economic value, etc., and achieve high decomposition reaction efficiency and broaden the scope of production Raw material routes, less impact on environmental pollution

Active Publication Date: 2012-09-12
CHONGQING SANSHENG IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Our country is short of sulfur and pyrite resources for sulfuric acid production. In order to meet the demand for sulfuric acid in various industries, a large amount of sulfuric acid is imported every year. Therefore, in recent years, the use of gypsum and various chemical gypsum and its potential sulfur resources to produce sulfuric acid has been paid attention to by all parties. , so while developing the sulfuric acid industry from gypsum, we actively develop SO 2 Producing sodium pyrosulfite (sodium sulfite), making sulfuric acid from raw gypsum, and decomposing SO 2 The concentration is only 7-9%. Because the low-concentration sulfur dioxide gas contains too many impurity gases with oxidizing properties, it is easy to produce sodium sulfate by side reaction in the production process of sodium pyrosulfite (sodium sulfite), so that the prepared sodium pyrosulfite ( or sodium sulfite) with low concentration and lost economic value, it is impossible to replace sulfur or pyrite acid with high concentration of SO 2 , so the current gypsum acid production technology can not meet the needs of the production of sodium metabisulfite

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A kind of production method of sodium pyrosulfite or sodium sulfite, carries out according to the following steps:

[0029] 1. Raw material equipment: 85% gypsum, 6% coke, 3% yellow sand, 4% shale, and 2% iron powder are used as raw materials by mass percentage, and the gypsum is CaSO 4 Gypsum and coke with a content of ≥85% are cokes with a fixed carbon content of ≥75%. The sieve residue of gypsum with a particle size of 0.08mm is 18%, and the sieve residue of coke with a particle size of 0.2mm is less than 20%. To achieve this, the addition of raw material is added with a metering screw, so that the feeding is uniform and smooth, no material breakage occurs, the metering is accurate, and the adjustment is free;

[0030] 2. Calcination reaction in the rotary kiln: Add the raw material prepared above into the rotary kiln for calcination, and control the kiln speed of the rotary kiln at 1.5 rpm; The gun enters to ensure that the coal powder enters the kiln evenly and bu...

Embodiment 2

[0057] A kind of production method of sodium pyrosulfite, carries out according to the following steps:

[0058]1. Raw material equipment: 83% gypsum, 8% coke, 5% yellow sand, 2% shale, and 2% iron powder are used as raw materials by mass percentage, and the gypsum is CaSO 4 Gypsum and coke with a content of ≥85% are cokes with a fixed carbon content of ≥75%. The sieve residue of gypsum with a particle size of 0.08mm is 15%, and the sieve residue of coke with a particle size of 0.2mm is less than 20%. To achieve this, the addition of raw material is added with a metering screw, so that the feeding is uniform and smooth, no material breakage occurs, the metering is accurate, and the adjustment is free;

[0059] 2. Calcination reaction in the rotary kiln: add the raw material prepared above into the rotary kiln for calcination, control the kiln speed of the rotary kiln at 2.5 rpm; The gun enters to ensure that the coal powder enters the kiln evenly and burns. The primary air vo...

Embodiment 3

[0066] A kind of preparation method of sulfur dioxide industrial raw material gas, carry out according to the following steps:

[0067] 1. Raw materials: 88% gypsum, 4% coke, 3% yellow sand, 4% shale, and 1% iron powder are used as raw materials by mass percentage, and the gypsum is CaSO 4 Gypsum and coke with a content of ≥85% are cokes containing fixed carbon ≥75%. The sieve residue of gypsum with a particle size of 0.08mm is 20%, and the sieve residue of coke with a particle size of 0.2mm is less than 20%. To achieve this, the addition of raw material is added with a metering screw, so that the feeding is uniform and smooth, no material breakage occurs, the metering is accurate, and the adjustment is free;

[0068] 2. Calcination reaction in the rotary kiln: add the raw material prepared above into the rotary kiln for calcination, control the kiln speed of the rotary kiln at 2.0 rpm; The gun enters to ensure that the coal powder enters the kiln evenly and burns. The primar...

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Abstract

The invention relates to a method for producing sodium metabisulfite or sodium sulphite. The method comprises the following steps of: firstly calcining the gypsum and coke serving as raw materials in a rotary kiln to prepare gas sulphur dioxide; then generating the gas sulphur dioxide subjected to purification treatment into a suspension liquid of the sodium metabisulfite or sodium sulphate, controlling the pH value of the suspension liquid to be 3.8-4.1, carrying out centrifugal dehydration on the suspension liquid by using a centrifugal machine, then drying and separating to obtain the finished product sodium metabisulfite or sodium sulphite, and absorbing tail gases by using a tail gas washing tower; and in the preparation process of the gas sulphur dioxide, controlling the content of O2 of the tail gases in the rotary kiln to be 0.05%-1.0% and the content of CO to be less than 0.4% according to the weight percentage content. The purities of sodium metabisulfite and sodium sulphite product prepared by using the method can respectively reach up to 97.5%-98.5wt% and more than 93wt% and is completely in line with national standards. According to the method, the route of raw materials for producing the sodium metabisulfite is widened.

Description

technical field [0001] The invention relates to a method for preparing high-concentration SO2 by utilizing gypsum 2 The invention relates to a method for producing sodium pyrosulfite (sodium sulfite) by using kiln gas, which belongs to the field of chemical technology and the field of utilization of industrial solid waste resources. Background technique [0002] Sodium metabisulfite (Na 2 S 2 o 5 ) is an important sulfite, which can be used as an antioxidant in food and medicine, a bleaching agent for fibers and their products, a raw material for sulfite pulp, a raw material for organic synthesis, and a reducing agent in chemical reactions. Sulfur dioxide is one of the main raw materials for the production of sodium pyrosulfite, and the amount of sulfur dioxide used to produce 1 ton of sulfuric acid can basically produce 1 ton of sodium pyrosulfite. Production of sodium pyrosulfite (sodium sulfite) chemical reaction equation: [0003] 2NaHSO 3 +Na 2 CO 3 =2Na 2 SO ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01D5/14
Inventor 杨兴志潘先文
Owner CHONGQING SANSHENG IND CO LTD
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