Arsenic-containing gypsum recycling treatment method and application of the treated and recycled low-arsenic gypsum

A technology of recycling and gypsum, applied in the field of waste recycling, can solve the problems of high arsenic gypsum being unable to be used twice, arsenic pollution, etc., and achieve the effects of improving secondary utilization rate, high safety, and improving resource utilization rate.

Active Publication Date: 2019-11-01
SHENYANG INST OF APPL ECOLOGY CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the hydrolysis of calcium arsenate and calcium arsenite with sulfuric acid, the formed gypsum (calcium sulfate) will combine with the arsenic dissolved from calcium arsenate and / or calcium arsenite to produce a large amount of arsenic-containing gypsum, and The arsenic content in gypsum is as high as 1.5%. High-arsenic gypsum cannot be directly used for secondary use, and its stacking or burying in the environment has the risk of causing arsenic pollution in the environment

Method used

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  • Arsenic-containing gypsum recycling treatment method and application of the treated and recycled low-arsenic gypsum
  • Arsenic-containing gypsum recycling treatment method and application of the treated and recycled low-arsenic gypsum
  • Arsenic-containing gypsum recycling treatment method and application of the treated and recycled low-arsenic gypsum

Examples

Experimental program
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Effect test

Embodiment 1

[0042] The source of arsenic-containing gypsum: the arsenic-calcium slag obtained by one-step neutralization of arsenic-containing polluted acid by a heavy non-ferrous smelting enterprise in Yunnan was used as raw material to remove arsenic and fix arsenic by acid leaching and scorodite precipitation method; The composition content of arsenic gypsum is: Ca21wt.%, As1.81wt.%, Cu1549mg / kg, Zn672mg / kg, Pb977mg / kg and Cd391mg / kg. Add 500g of arsenic-calcium slag into 500mL of clear water and make a mixed slurry of arsenic-calcium slag under sufficient stirring conditions. Use a peristaltic pump to add the mixed slurry of arsenic-calcium slag into the sulfuric acid solution and adjust the pH value with 6mL / L sulfuric acid To 2.0, solid-liquid separation to obtain arsenic-containing gypsum and arsenic-containing solution, the arsenic-containing solution can be removed and fixed by scorodite precipitation process well known in the industry.

[0043] Recycling treatment of arsenic-con...

Embodiment 2

[0051] The recrystallization temperature was controlled to be 120° C., and other processes and parameters were the same as in Example 1.

[0052] Low-arsenic gypsum was observed using a scanning electron microscope, and the observation results can be found in Figure 5 . Depend on figure 1 with Figure 5 It can be seen from the comparison that the arsenic-containing gypsum originally had a short and thick rod-like structure, but after recrystallization treatment at 120 °C, its morphology changed significantly and became a regular cuboid shape.

[0053] Extend the recrystallization time to 24h, and adopt the same test method as in Example 1, under different recrystallization time conditions, carry out the leaching toxicity test on the obtained low-arsenic gypsum. The test results are shown in Table 2; The arsenic leaching figure of low-arsenic gypsum under the condition of crystallization time, see Image 6 .

[0054] Table 2 Example 2 The amount of arsenic leached from lo...

Embodiment 3

[0058] Source of arsenic-containing gypsum: lime arsenic-containing wastewater (H 2 SO 4 : 100g / L; As(V): 6g / L) adjusted to pH 12.0, solid-liquid separation to obtain arsenic-calcium slag and low-arsenic waste liquid, adding arsenic-calcium slag to sulfuric acid to obtain arsenic-containing gypsum and arsenic-containing solution ( The addition method is as in Example 1), and the arsenic-containing solution can be removed and fixed by the well-known scorodite precipitation process in the industry.

[0059] Recycling treatment of arsenic-containing gypsum: Add 100g of arsenic-containing gypsum into 400mL of hydrochloric acid solution with a concentration of 6moL / L, stir well, and mix evenly to obtain a slurry; then raise the temperature of the slurry to 120°C and keep it warm for 4 hours for dissolution and recrystallization to obtain Solid-liquid mixture; finally, the solid-liquid mixture is taken out and cooled to room temperature, and the solid-liquid is separated to obtain ...

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Abstract

The invention belongs to the technical field of waste recycling treatment, and particularly relates to an arsenic-containing gypsum recycling treatment method and application of the treated and recycled low-arsenic gypsum. The method comprises the following steps: mixing arsenic-containing gypsum with an acidic solution, and then sequentially carrying out recrystallization and solid-liquid separation treatment to obtain low-arsenic gypsum and an arsenic-containing solution. Arsenic-containing gypsum is used as a raw material, and the industrial waste is recycled. The arsenic-containing gypsumis mixed with an acidic solution, so that an acidic recrystallization environment is guaranteed, which is beneficial to promoting dissolution and recrystallization of the arsenic-containing gypsum; HAsO4<2-> released from the arsenic-containing gypsum is converted into arsenide containing H2AsO4<-> or H3AsO4, so that arsenic is prevented from being embedded into new gypsum crystal lattices formedby dissolution and recrystallization again, and the low-arsenic gypsum with extremely low arsenic content is obtained. Experimental data show that the arsenic leaching concentration of the low-arsenicgypsum obtained through the method is smaller than 0.2 mg/L, and the arsenic content is lower than 35 mg/kg.

Description

technical field [0001] The invention belongs to the technical field of waste resource treatment, in particular to a method for resource treatment of arsenic-containing gypsum and the application of the obtained low-arsenic gypsum. Background technique [0002] Arsenic is a toxic element that mainly exists in the form of sulfide and is associated with other metals, such as gold, copper, lead, nickel, cobalt and zinc, etc. A large amount of arsenic-containing acidic wastewater (polluted acid) and arsenic sulfide slag will be produced. The arsenic in polluted acid and arsenic sulfide slag must be fixed in a stable compound to eliminate environmental pollution. Therefore, the removal and fixation technology of arsenic in the field of non-ferrous metal smelting research projects has always been a research hotspot. [0003] Gypsum, as one of the main by-products of arsenic-containing acid and solid waste treatment, is often doped with a large amount of arsenic in its crystal stru...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B7/42A62D3/36C04B11/26C04B22/14
CPCA62D3/36A62D2101/40C04B7/425C04B11/26C04B22/146
Inventor 贾永锋马旭王少锋
Owner SHENYANG INST OF APPL ECOLOGY CHINESE ACAD OF SCI
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