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Method for removing impurities and decoloration of desulfurized gypsum

A desulfurization gypsum and decolorization technology, applied in chemical instruments and methods, calcium/strontium/barium sulfate, inorganic chemistry, etc., can solve the problems of unfavorable resource utilization of desulfurization gypsum, waste of water resources, high corrosion of chloride ions, etc., to achieve Simplify operation, promote dispersion, and reduce environmental pollution

Inactive Publication Date: 2019-04-05
TIANJIN BOHUA YONGLI CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the decolorization effect of this method is obvious, it still solves the problems of waste of water resources and environmental pollution in the washing method. At the same time, the use of hydrochloric acid introduces a new impurity removal-chloride ion. It is also not conducive to the resource utilization of desulfurization gypsum

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Embodiment 1: the specific operations are as follows

[0018] (1) Dry the desulfurized gypsum in an oven at 100°C for 2 hours to remove free water to obtain desulfurized gypsum on a dry basis;

[0019] (2) Grinding the desulfurized gypsum on a dry basis, sieving through an 80-mesh square hole sieve, and taking the under-sieve;

[0020] (3) Add the undersize and deionized water into the beaker at a mass ratio of 1:3, then place the beaker in an ultrasonic device, and wash with ultrasonic water for 30 minutes at 30°C, wash with water while stirring, and filter with suction , get filter cake;

[0021] (4) Put the desulfurized gypsum after ultrasonic washing and 1mol / L dilute sulfuric acid into a three-necked flask at the ratio of adding 150ml of 1mol / L dilute sulfuric acid per 10g of desulfurized gypsum, and stir and react at 80°C for 2h;

[0022] (5) Immediately after the reaction, the reaction solution was filtered by suction to obtain a mother solution without precipi...

Embodiment 2

[0024] Embodiment 2: specific operations are as follows

[0025] (1) Dry the desulfurized gypsum in an oven at 110°C for 1.5 hours to remove free water to obtain desulfurized gypsum on a dry basis;

[0026] (2) Grinding the desulfurized gypsum on a dry basis, sieving through a 90-mesh square hole sieve, and getting the under-sieve;

[0027] (3) Add the undersize and deionized water into the beaker at a mass ratio of 1:4, then place the beaker in an ultrasonic device, wash it with ultrasonic water for 20 minutes at 40°C, wash with water while stirring, and filter with suction , get filter cake;

[0028] (4) Put the desulfurized gypsum after ultrasonic washing and 1mol / L dilute sulfuric acid into a three-necked flask at a ratio of 200ml of 1mol / L dilute sulfuric acid per 10g of desulfurized gypsum, and stir and react at 90°C for 2.5h;

[0029] (5) Immediately after the reaction, the reaction solution was filtered by suction to obtain a mother solution without precipitation. Th...

Embodiment 3

[0031] Embodiment 3: specific operations are as follows

[0032] (1) Dry the desulfurized gypsum in an oven at 120°C for 1 hour to remove free water to obtain desulfurized gypsum on a dry basis;

[0033] (2) Grinding the desulfurized gypsum on a dry basis, sieving through a 100-mesh square hole sieve, and getting the under-sieve;

[0034] (3) Add the undersize and deionized water into the beaker at a mass ratio of 1:5, then place the beaker in an ultrasonic device, and wash with ultrasonic water for 15 minutes at 50°C, wash with water while stirring, and filter with suction , get filter cake;

[0035] (4) Put the desulfurized gypsum after ultrasonic washing and 1mol / L dilute sulfuric acid into a three-necked flask at a ratio of 250ml of 1mol / L dilute sulfuric acid per 10g of desulfurized gypsum, and stir and react at 85°C for 3h;

[0036] (5) Immediately after the reaction, the reaction solution was filtered with suction to obtain a mother solution without precipitation, and...

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Abstract

The invention discloses a method for removing impurities and decoloration of desulfurized gypsum. According to the method, dry grinding, sieving, ultrasonic treatment and the like are performed on the desulfurized gypsum, which can promote the dispersion of the gypsum crystals, facilitate the removal of impurities on the surface of the crystal and between the crystals, improve the washing efficiency, reduce the water consumption, washing waste discharge and washing times, simplify the operation and reduce environmental pollution. Then, on the basis of ultrasonic washing, heating and picklingwith sulfuric acid can promote the release of colored impurities wrapped in the crystal. Immediate suction filtration after pickling can prevent impurities from being re-wrapped in crystals during recrystallization process, thereby improving the effect of impurity removal and decolorization. As sulfuric acid substitutes hydrochloric acid, introduction of new impurities is avoided. After the operation of the method, the impurity content of desulfurized gypsum is reduced from 2.75% to less than 1.27%, and the whiteness is increased from 30.26% to more than 90.69%.

Description

technical field [0001] The invention relates to the field of inorganic salt technology, in particular to a method for removing impurities and decolorizing desulfurized gypsum. Background technique [0002] Desulfurization gypsum, also known as flue gas desulfurization gypsum, FGD gypsum (Flue Gas Desulphurization Gypsum), is a by-product of flue gas desulfurization in coal-fired power plants, and its main component is calcium sulfate dihydrate (CaSO 4 2H 2 O), and about 10% of free water and a small amount of fly ash, metal oxides and other impurities. The added value of desulfurized gypsum itself is low. With the rapid development of my country's industry, nearly 100 million tons of desulfurized gypsum are discharged every year. The large amount of desulfurized gypsum not only occupies land, wastes resources, but also pollutes the environment. Sustainable development of gas desulfurization. Therefore, it is urgent to realize resource utilization of desulfurized gypsum. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/46
CPCC01F11/468C01P2006/65C01P2006/80
Inventor 张波庞栓林聂增来李治水苗淳李越杨志波刘宇娜李满枝李云辉
Owner TIANJIN BOHUA YONGLI CHEM IND