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Wet chemical recovery method of lead and zinc in burning solid products

A recovery method and solid product technology, applied in the direction of solid waste removal, lead sulfate, zinc sulfate, etc., can solve the problems of uneconomical, high price, large energy consumption, etc.

Active Publication Date: 2010-09-08
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

One method is to convert lead and zinc into chlorides, and use their vaporization temperature and freezing point for gasification separation. This method requires high temperature and consumes a lot of energy.
The other is to use sodium acetate and calcium nitrate to recover lead, and ammonium acetate and nitric acid to recover zinc. This method is expensive and uneconomical because the price of the reagents used is relatively high.

Method used

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  • Wet chemical recovery method of lead and zinc in burning solid products
  • Wet chemical recovery method of lead and zinc in burning solid products
  • Wet chemical recovery method of lead and zinc in burning solid products

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0027] The product of a waste incineration fly ash melting system is recovered lead and zinc according to the present invention, and the determination results of the original ash are shown in Table 1.

[0028] Table 1 Composition of molten fly ash 1

[0029]

[0030] The first step is the dechlorination process. The main purpose of this step is to allow lead and zinc to enter the residue, and unwanted elements such as chlorine to enter the filtrate. Take 50 kg of molten fly ash, put it into a cylindrical reaction vessel, add 500 kg of water, stir with a mechanical stirrer at a speed of 300 rpm, and then add 7.848 L of NaOH solution with a mass concentration of 25% when stirring, and monitor the pH value of the solution while stirring. The reaction time is 20 minutes. The change of pH and alkali addition amount in the dechlorination process with time is shown in figure 2 . Precipitate then, filter, obtain wet residue quality 63.38kg, know that its dry basis quality is 3...

example 2

[0035] The product of a waste incineration fly ash melting system is recovered lead and zinc according to the present invention, and the determination results of the original ash are shown in Table 1.

[0036] Table 2 Composition of molten fly ash 2

[0037]

[0038] The first step is the dechlorination process. The main purpose of this step is to allow lead and zinc to enter the residue, and unwanted elements such as chlorine to enter the filtrate. Take 50kg of molten fly ash, put it into a cylindrical reaction vessel, add 500kg of water, stir with a mechanical stirrer at a speed of 300rpm, add 5.191L of 25% NaOH solution while stirring, and monitor the change of the pH value of the solution while stirring, and the reaction time is 5 minutes . Precipitate then, filter, obtain wet residue quality 117.9kg, know that its dry basis quality is 29.43kg by measuring moisture content. After testing the components of the filtrate and residue, the material balance calculation res...

example 3-13

[0043] The fly ash used in Example 1 is processed by this method, and the processing results under different operating parameters are shown in the table below.

[0044]

[0045]

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PUM

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Abstract

The invention discloses a wet chemical recovery method of lead and zinc in burning solid products, which comprises the following steps of: firstly, using a sodium hydroxide solution for washing fly ash to generate lead hydroxide and zinc hydroxide precipitate; removing chloride ions through being dissolved in water; then, making the precipitate washed in the last work procedure react with sulfuric acid; making the lead hydroxide react with the sulfuric acid to generate lead sulfate precipitate; dissolving the zinc hydroxide into the sulfuric acid to generate a zinc sulfate solution so that the lead and zinc separation can be realized; then, making the obtained solution react with a sodium hydroxide solution; and making the zinc sulfate react with hydroxide to generate zinc hydroxide precipitate for separating out the zinc. The invention can effectively separate out the heavy metal of lead and zinc in the fly ash, can reduce the environment pollution while realize the effect of changing waste materials into resources, and is particularly applicable to the fly ash generated by burning solid waste materials with high lead and zinc content and burning ash of other fuel after the enrichment.

Description

technical field [0001] The invention belongs to the field of solid waste treatment and resource recovery and utilization, and relates to a wet chemical recovery method for lead and zinc in solid products, and is especially suitable for the use of molten fly ash with high content of lead and zinc. Background technique [0002] Fuels usually contain some amount of metals. Taking the average content of metallic lead in fuel as an example, the content in coal is about 0.1-15ppm, the content in petroleum is about 2ppm, the content in municipal solid waste is as high as 100-500ppm, and the content in derived solid fuel is about 200ppm. The content is 16ppm, the ordinary sludge content is 102-216ppm, and the domestic sludge content is about 55-88ppm. During the combustion process, these metal elements are enriched in some solid combustion products through high-temperature gasification, low-temperature condensation and other processes. Although sometimes the degree of enrichment i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G21/20C01G9/06B09B3/00
Inventor 姚洪罗光前韩军
Owner HUAZHONG UNIV OF SCI & TECH
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