Method for treating tailings after extracting metal from electroplating sludge

A treatment method and electroplating sludge technology are applied in the field of treatment of tailings after metal extraction in electroplating sludge, which can solve problems such as incomplete leaching, and achieve the effects of easy control of conditions, reduction of process flow, and widening of application scope.

Inactive Publication Date: 2017-12-01
青川县天运金属开发有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Wet chemical leaching methods mainly include acid leaching, ammonia leaching, and biological leaching, but they all have the problem of incomplete leaching, and the heavy metal content in tailings still exceeds the environmental standard value. Therefore, most tailing

Method used

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  • Method for treating tailings after extracting metal from electroplating sludge

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] A treatment method for tailings after metal extraction in electroplating sludge: (the process flow chart is as follows figure 1 shown)

[0026] (1) Slurry: Pulverize the comprehensive electroplating sludge raw material containing copper, nickel, zinc, chromium, and cadmium. The main metal components of the raw material are shown in Table 1, and mixed with water at a mass ratio of 1:4 to obtain a mixed slurry. The solid ratio is 1~5:1;

[0027] (2) Acid leaching: fully stir the pulped sludge, and add 98% sulfuric acid until the pH value of the slurry is ≤0.5 and remains stable within 30 minutes;

[0028] (3) Pressure filtration: The sludge after acid leaching is subjected to solid-liquid separation, and the filter cake is washed with a dilute sulfuric acid solution with a pH value of 0.5 until the washing water is colorless, and the filtrate is collected;

[0029] (4) Two-stage pickling: Slurry the press-filtered filter cake and water at a mass ratio of 1:2, and adjust...

Embodiment 2

[0037] A method for treating tailings after metal extraction from electroplating sludge

[0038] The operation steps are the same as in the examples, except that the main metal components of the material are shown in Table 3, and the specific composition ratios in the finally obtained gypsum are shown in Table 4.

[0039] Table 3 List of main metal components of raw materials

[0040] .

[0041] Table 4 Composition list of gypsum products

[0042] .

[0043] Note: The determination of crystal water shall be carried out according to GB / T 5484, and the determination of sulfur trioxide shall be carried out according to GB / T 5484. According to the calculation method of 6.2 grade in GB / T5483-2008, the grade of gypsum (calcium sulfate dihydrate) is 85.34%.

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Abstract

The invention relates to the technical field of metal-containing hazard waste treatment and comprehensive utilization, and particularly relates to a method for treating tailings after extracting metal from electroplating sludge. The method comprises the following steps: pulping comprehensive sludge, adding sulfuric acid, and leading chromium, cadmium, copper, nickel, zinc and other heavy metals to enter a solution; extracting, performing filter pressing, and washing filter cake with water having a pH value of 0.5 until the washing water is colorless; and performing two-step pickling, press-filtering/alkali-washing and other steps to finally obtain gypsum of which the main ingredient is calcium sulfate dihydrate having dry basis content of more than 75 percent and accords with the requirement of GB/T5483-2008 (second grade), wherein the content of heavy metals including chromium, cadmium, copper, nickel and zinc is lower than the limit value of the national environmental quality standard for soil (third grade), the treated tailings can be directly used in cement manufacture instead of natural gypsum, and the preparation process cannot generate waste water or waste residue and is friendly to the environment.

Description

technical field [0001] The invention relates to the technical field of metal-containing hazardous waste treatment and comprehensive utilization, in particular to a treatment method for tailings after metal extraction from electroplating sludge. Background technique [0002] Electroplating sludge contains a large amount of toxic heavy metals such as copper, nickel, zinc, chromium, and cadmium. At present, the main technologies for treating electroplating sludge include solidification / stabilization technology, materialization technology, thermochemical treatment technology, and wet chemical treatment technology. Solidification / stabilization technology reduces the dissolution rate of harmful substances and stabilizes heavy metals by adding appropriate additives. Materialization technology uses electroplating sludge as a raw material or auxiliary material to produce building materials or other materials. Both methods cannot achieve electroplating sludge. recycling of valuable me...

Claims

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Application Information

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IPC IPC(8): C04B11/26
CPCC04B11/26
Inventor 王修海贾智慧
Owner 青川县天运金属开发有限公司
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