Method for decomposing phosphogypsum to produce SO2

A technology of SO2 and phosphogypsum, applied in chemical instruments and methods, sustainable manufacturing/processing, inorganic chemistry, etc., can solve the problems of high energy consumption and high cost of sulfuric acid, and achieve low energy consumption, good sealing performance, simple and reasonable process Effect

Inactive Publication Date: 2013-09-11
昆明隆青化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The object of the present invention is to provide a method for the decomposition of phosphogypsum in view of the excessively high energy consumption in the decomposition of existing phosphogypsum, which causes the cost of producing sulfuric acid from phosphogypsum to be too high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Use phosphogypsum as raw material, add 3% CL mixture to the raw material as a mineralizer, then mix the prepared material and coke at a weight ratio of 22.67:1, grind to 200 mesh, homogenize, and add high-quality clay for bonding ellipsoid-shaped raw material pellets, pellet size: 50mm×30mm×20mm, and dried, and the dried raw raw ℃ into the reduction section, the temperature rises to 796 ℃ to start reduction, there is SO 2 The gas overflows, and the temperature is kept at 820°C for 1 hour and 10 minutes. The induced draft fan draws out the furnace gas, and the dust is removed by gravity sedimentation. After electrostatic dust removal, SO 2 , The reduction rate is 98.93%.

Embodiment 2

[0027] Example 1 was repeated with the following difference: 3% F mixture was added to the raw material as a mineralizer. Preheat to 680°C, enter the reduction section, heat up to 800°C to start reduction, there is SO 2 Overflow, heat preservation at 820°C for 1 hour and 10 minutes, and the reduction rate reaches 98.86%.

Embodiment 3

[0029] Repeat embodiment 1, have following difference: add composite mineralizer in raw material. The compound mineralizer constitutes 1.2% CL mixture and 1.8% F mixture. Preheat to 650°C, enter the reduction section, heat up to 798°C with SO 2 Overflow, heat preservation at 820°C for 1 hour and 10 minutes, the reduction rate is 99.00%.

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Abstract

Relating to the technical field of production of sulfuric acid from phosphogypsum and co-production of cement, the invention discloses a method for decomposing phosphogypsum to produce SO2 so as to solve the technical problems that excessive energy consumption of phosphogypsum decomposition and too high sulfuric acid preparation cost in the prior art restrict the development, utilization and industrialization of phosphogypsum. The method includes: adopting a vertical retort as main production equipment, adding a mineralizer into phosphogypsum, mixing the obtained mixture with coke in a weight ratio of 22.67:1, carrying out milling, homogenizing, pelletizing and drying, adding dry pellets into the vertical retort, taking coal gas as the fuel to preheat the vertical retort to600DEG C-700DEG C by flame isolation heating so as to enter a reduction section, raising the temperature to 820DEG C, conducting heat preservation for 1 hour and 20 minutes, letting a draught fan lead furnace gas out, and performing two-stage dedusting, thus obtaining the needed product SO2. The energy consumption of the method accounts only 45%-50% of that of the prior art. Thus, the method provided in the invention plays an energy-saving and emission reduction role in subsequent production of sulfuric acid and co-production of cement.

Description

[0001] The present invention relates to the technical field of sulfuric acid co-production cement produced by phosphogypsum, more specifically, the present invention relates to using phosphogypsum as raw material to decompose SO 2 method. Background technique [0002] Phosphogypsum is a solid industrial waste produced during the wet process of phosphoric acid production, and its main chemical composition is CaSO 4 2H 2 O. and contains a small amount of SIO 2 、AL 2 o 3 , Fe 2 o 3 、C a O, MgO, trace metal ions and radioactive elements, and undecomposed phosphate rock powder, P 2 o 5 , F - and free acids and other impurities. In the process of producing wet-process phosphoric acid by dihydric method, 4-5t of phosphogypsum is produced for every 1t of phosphoric acid produced. China emits more than 20 million tons of phosphogypsum every year, but the utilization rate is less than 10%. Untreated phosphogypsum stacking not only takes up a lot of land and money, wastes a ...

Claims

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Application Information

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IPC IPC(8): C01B17/50
CPCY02P20/10
Inventor 车建青曾繁端
Owner 昆明隆青化工有限公司
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