Technology for cyclic decomposing, transforming and using ardealite with two-step method

A technology of phosphogypsum and two-step method, which is applied in the field of cyclic decomposition and transformation of phosphogypsum by two-step method, which can solve the problems of low market demand for converted products and high cost of comprehensive utilization of phosphogypsum, so as to reduce raw material cost, easy process, The effect of low energy consumption

Inactive Publication Date: 2016-11-16
WUHAN INSTITUTE OF TECHNOLOGY
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  • Abstract
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Problems solved by technology

[0009] The present invention aims at the deficiencies of the prior art, and aims to provide a two-step process for cyclically decomposing and tran

Method used

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  • Technology for cyclic decomposing, transforming and using ardealite with two-step method
  • Technology for cyclic decomposing, transforming and using ardealite with two-step method
  • Technology for cyclic decomposing, transforming and using ardealite with two-step method

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Embodiment 1

[0036] A two-step recycling process for decomposing and transforming phosphogypsum, comprising the following steps:

[0037] (1) The concentration is 9.16wt% NaOH solution, according to sodium hydroxide and CaSO 4 The theoretical molar amount required for the reaction is 2:1, and it is added to the reactor containing the phosphogypsum raw material; at the same time, ethanol is added in a proportion of 0.2wt% of the phosphogypsum mass, and at room temperature with a stirring speed of 6.3m / s, Stirring reaction 10min; Then slowly add excess NaOH solution (the molar weight of sodium hydroxide is CaSO 40.15 times the molar weight), continue to stir the reaction for 5min. Then stop stirring, the slurry is settled and filtered, and the filter residue is countercurrently washed twice to obtain a mass concentration of 15.03% Na 2 SO 4 Solution and Calcium Slag, CaSO 4 The decomposition conversion rate is 96.25%. Calcium slag is separated into particle sizes below 20 μm by hydrauli...

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Abstract

The invention belongs to the technical field of ardealite comprehensive utilization and particularly relates to a technology for cyclic decomposing, transforming and using of ardealite with a two-step method. The technology comprises the steps that firstly, ardealite is decomposed and transformed into sodium sulfate and calcium hydroxide, in other words, a sodium hydroxide solution and ethyl alcohol are added into the ardealite raw material, a reaction is carried out under the room-temperature stirring condition, solid and liquid are separated through settling and filtering after the reaction is finished, a sodium sulfate solution and calcium residues are obtained, calcium hydroxide in the calcium residues is separated from other impurity ingredients with a grading method, a calcium hydroxide product with the content of Ca(OH)2 higher than or equal to 90% is obtained, and the remaining impurities can serve as accessories for preparing cement or serve as building raw materials; secondly, a three-grade adverse current bipolar membrane electrodialysis system is used for transforming the sodium sulfate solution into sulfuric acid and a sodium hydroxide solution, wherein the sodium hydroxide solution can be circularly used for decomposing and transforming ardealite, and sulfuric acid can be circularly used for decomposing phpsphorite for preparing phosphate.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of phosphogypsum, and in particular relates to a two-step process for circularly decomposing, transforming and utilizing phosphogypsum. Background technique [0002] Phosphate fertilizer enterprises produce high-concentration phosphate fertilizers and compound fertilizers. They generally use sulfuric acid to decompose phosphate rock to produce phosphoric acid, and then use phosphoric acid to produce high-concentration phosphate fertilizers and compound fertilizers. When sulfuric acid is used to decompose phosphate rock, the phosphorus-containing minerals in the phosphate rock react with sulfuric acid to generate phosphoric acid and insoluble phosphogypsum (CaSO 4 ·xH 2 O). Some common impurity minerals in phosphate rock, such as calcite and dolomite, will also react with sulfuric acid to form phosphogypsum. [0003] Ca 5 (PO 4 ) 3 F+5H 2 SO 4 +5xH 2 O→5CaSO 4 ·xH 2 O+3...

Claims

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Application Information

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IPC IPC(8): C01D5/10C01D1/04C01F11/16C01B17/74
CPCC01B17/745C01D1/04C01D5/10C01F11/16
Inventor 张泽强何东升张汉泉李冬莲
Owner WUHAN INSTITUTE OF TECHNOLOGY
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