Phosphogypsum composite pretreatment technique

A phosphogypsum and pretreatment technology, applied in the field of renewable resources and environmental protection, can solve the problems of low utilization rate of phosphogypsum and achieve significant economic benefits

Inactive Publication Date: 2012-10-17
广西凯浩环保材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there is currently no good pretreatment process for p...

Method used

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  • Phosphogypsum composite pretreatment technique
  • Phosphogypsum composite pretreatment technique

Examples

Experimental program
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Effect test

Embodiment 1

[0018] raw material source

[0019] Phosphogypsum slag—the discharge port produced by Guangxi Luzhai Fertilizer Co., Ltd. Phosphogypsum slag contains about 30% acidic water, 15% solid impurities, and 35% SO 3 , 70% CaSO 4 2H 2 O, pH=2, the particles are uneven and grayish black.

[0020] Industrial wastewater—wastewater from a phosphate rock ball mill workshop in a fertilizer factory.

[0021] Alkaline calcium-enhancing fluid—a slurry made of lime produced by surrounding lime factories, with a pH value of about 12.

[0022] process flow

[0023] Take phosphogypsum slag directly from the slag outlet of the chemical enterprise, discharge it into a 30-mesh vibrating screen, and wash the phosphogypsum slag with industrial wastewater to remove about 10% of the hard mineral impurities with coarser particle sizes. The phosphorus obtained after washing The gypsum slurry is added to the phosphogypsum mass of 2% alkaline calcium solution to adjust the pH value to 7 ± 1, and then se...

Embodiment 2

[0025] raw material source

[0026] Phosphogypsum slag——with embodiment 1.

[0027] Industrial wastewater—wastewater from a phosphoric acid washing process in a chemical fertilizer plant.

[0028] Alkaline calcium-increasing liquid——It is made by diluting and stirring calcium carbide slag discharged from caustic soda production in Liuzhou Chemical Plant, and its pH value is about 14.

[0029] process flow

[0030] Add 1% alkaline calcium-enhancing solution to adjust the pH value to 7±1, and refer to Example 1 for others.

Embodiment 3

[0032] raw material source

[0033] Phosphogypsum slag——with embodiment 1.

[0034] Industrial wastewater—wastewater from a phosphate rock ball mill workshop in a fertilizer factory.

[0035] Alkaline calcium-increasing liquid——It is made by diluting and stirring the calcium-increasing alkali slag discharged from Guangxi Fengtang Paper Industry, and its pH value is about 13. process flow

[0036] Add 1.5% alkaline calcium-increasing solution to adjust the pH value to 7±1, and refer to Example 1 for others.

[0037] After testing, the high-purity phosphogypsum of Examples 1 to 3 contains less than 10% water, pH 7±1, SO 3 Up to 43% or more, CaSO 4 2H 2 The O content is more than 90%, the soluble phosphorus is less than 0.01%, the total phosphorus is less than 0.05%, and the impurities are less than 1%. See Table 1 for details.

[0038] Components and properties of table 1 embodiment 1 to 3 high-purity phosphogypsum

[0039]

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Abstract

The invention discloses a phosphogypsum composite pretreatment technique which comprises the following steps: directly taking phosphogypsum slag from a slag discharge port of a chemical industry enterprise, passing through a 30-mesh vibrating screen for separation, and meanwhile flushing the phosphogypsum slag with industrial wastewater of the chemical industry enterprise to remove hard mineral impurities; adding an alkaline calcium-increase liquid which accounts for 1-2 wt% of phosphogypsum into the phosphogypsum slurry obtained by flushing so as to regulate the pH value to 7+/-1, sending into a stratification filter tank, stirring, standing, and removing a surface layer organic substance film and soluble impurities; and sending the stratified and purified phosphogypsum slurry into a vacuum filter to carry out vacuum filtration, thereby obtaining filter residues and a filtrate. According to the technique, the phosphogypsum slag at the discharge port of the chemical industry enterprise is directly utilized to extract the high-purity low-impurity high-grade phosphogypsum, thereby saving the stock place and lowering the transportation cost; and the raw material is from three wastes and does not generate secondary pollution, the intermediate product hard mineral impurities can be directly used commercially, and water can be used circularly, thereby greatly enhancing the comprehensive utilization ratio of the phosphogypsum and implementing organic unification of environmental, economical and social benefits.

Description

technical field [0001] The invention relates to the technical field of renewable resources and environmental protection, in particular to a phosphogypsum composite pretreatment process. Background technique [0002] Phosphogypsum is industrial waste discharged from the phosphoric acid or phosphate fertilizer industry and some synthetic detergent industries. The main component is calcium sulfate dihydrate (CaSO 4 2H 2 O), but it also contains undecomposed phosphate rock, unwashed phosphoric acid, calcium fluoride, sodium fluoride, iron-aluminum compounds, acid-insoluble organic matter, and muddy debris, which are harmful to human health and biological growth, and affect Impurities of gypsum product quality. Among them, soluble phosphorus prolongs the coagulation time and reduces the strength of hemihydrate gypsum; soluble fluorine in the form of NaF can make the crystals of the hydration product dihydrate gypsum coarse, reduce the degree of inter-crystal bonding, and weaken...

Claims

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Application Information

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IPC IPC(8): C04B11/26
Inventor 刘晓刚易伟朱中彩
Owner 广西凯浩环保材料股份有限公司
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