Flocculating and dehydrating method for treating waste slurry in process for preparing polyaluminum chloride by aluminium ash method

A technology of polyaluminum chloride and waste mud, which is applied in the direction of dewatering/drying/concentrating sludge treatment, etc., can solve the problems of lack of effective treatment methods, different content of waste mud, and inability to directly convert the treatment process, so as to achieve excellent flocculation and dehydration. effect, improved recovery rate, ease of disposal and recycling effect

Active Publication Date: 2017-03-22
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the content of the waste slag from the production of aluminum profiles is different from that of the waste mud generated from the production of polyaluminium chloride, and the treatment processes of the two cannot be directly converted.
[0006] In summary, there is still no low-cost, high-efficiency, and environmentally friendly method to deal with the waste slurry produced by the alumin

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] The first step is to use aluminum ash as raw material and add C 12 Alkyl sodium sulfate, stirring, the Zeta potential of the mud supernatant is fine-tuned to 43mV, and the polyaluminum chloride solution is separated;

[0019] In the second step, the remaining mud liquid is precipitated, and then the waste mud at the bottom is taken out. At this time, the solid content of the waste mud is 52%;

[0020] In the third step, a cationic polyacrylamide P (DAC-AM) flocculant with a cationic degree of 70% and an intrinsic viscosity of 13.4 dL / g is added to the waste mud obtained in the second step, and the dosage is 75 mg / L waste mud Slurry, stir evenly, observe the flocculation and solid-liquid separation;

[0021] The fourth step is dehydration with a filter device, and then the obtained filter cake is taken out to obtain a loose lumpy mud cake after dehydration, and the measured solid content is 62.5% by mass fraction.

Embodiment 2

[0023] The first step is to use aluminum ash as raw material and add C 8 Alkyl sodium sulfate, stirring, the Zeta potential of the mud supernatant is fine-tuned to 47mV, and the polyaluminum chloride solution is separated;

[0024] In the second step, the remaining mud liquid is precipitated, and then the waste mud at the bottom is taken out. At this time, the solid content of the waste mud is 50%;

[0025] The third step is to add P(DAC-AM) flocculant with a cationic degree of 90% and an intrinsic viscosity of 12.0dL / g to the waste mud obtained in the second step, and the dosage is 30mg / L of waste mud, and stir evenly. Observe the flocculation and solid-liquid separation;

[0026] The fourth step is dehydration with a filter device, and then the obtained filter cake is taken out to obtain a loose block mud cake after dehydration, and the measured solid content is 60.0% by mass fraction.

Embodiment 3

[0028] The first step is to use aluminum ash as raw material and add C 14 Alkyl sodium sulfate, stirring, the Zeta potential of the mud supernatant is fine-tuned to 40mV, and the polyaluminum chloride solution is separated;

[0029] In the second step, the remaining mud liquid is precipitated, and then the bottom waste mud is taken out. At this time, the solid content of the waste mud is 55%;

[0030] In the third step, a cationic polyacrylamide P (DAC-AM) flocculant with a cationic degree of 50% and an intrinsic viscosity of 17.0 dL / g is added to the waste mud obtained in the second step, and the dosage is 110 mg / L waste mud Slurry, stir evenly, observe the flocculation and solid-liquid separation;

[0031] The fourth step is dehydration with a filter device, and then the resulting filter cake is taken out to obtain a loose lumpy mud cake after dehydration, and the measured solid content is 61.6% by mass fraction.

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Abstract

The invention discloses a flocculating and dehydrating method for treating waste slurry in a process for preparing polyaluminum chloride by an aluminium ash method. The method comprises the following steps: firstly Zeta potential of the waste slurry in the process for preparing polyaluminum chloride is adjusted by using an anionic surfactant sodium alkyl sulfate; a polyaluminum chloride solution is separated, rest waste slurry is precipitated, the solid content of the waste slurry is adjusted, cation-type polyacrylamide is added, cation-type polyacrylamide is dispersed based on self-diffusion and stirring, and flocculation and dehydration are carried out; finally, after flocculation and dehydration, the waste slurry is filtered, in order to realize solid-liquid separation. The solid content of the waste slurry is improved from 60.0%-62.5% from 50.0-55.0%, slurry with high acid solution content is converted into loose blocks, the treated waste slurry can be directly transported, in order to facilitate disposal and recycling. In addition, the volume of the waste slurry is reduced by about 21% by the flocculating and dehydrating method, and 20-30% of the volume of the polyaluminum chloride solution is recycled. The Zeta potential of the waste slurry is adjusted for realizing flocculating and dehydrating effects, and the method has theoretical significance and practical value in industrial production process.

Description

technical field [0001] The invention belongs to the technical field of flocculation and dehydration of waste mud, and in particular relates to a flocculation and dehydration method for treating waste mud of aluminum ash legally produced polyaluminium chloride process. Background technique [0002] Polyaluminum chloride is a well-known inorganic polymer flocculant widely used in wastewater treatment. Our country began production and application in the early 1970s, and became the main flocculation dehydrating agent in my country since the 1990s. The production methods of polyaluminium chloride can be divided according to different sources of raw materials: aluminum oxide method (such as bauxite, kaolin, coal gangue, etc.), aluminum hydroxide method and aluminum ash method (such as aluminum slag, aluminum scrap, aluminum gray, etc.). The production of polyaluminum chloride from aluminum ash has the characteristics of low cost, easy availability of raw materials, and simple pr...

Claims

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Application Information

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IPC IPC(8): C02F11/14
Inventor 张跃军符星琴陈婷婷刘程钟学鹏
Owner NANJING UNIV OF SCI & TECH
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