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Preparation method of aluminum-containing flocculant through extraction of aluminum from sludge

A technology of aluminum flocculation and sludge, applied in sludge treatment, chemical instruments and methods, water/sludge/sewage treatment, etc., can solve the problems of poor quality of flocculant products and achieve good results

Inactive Publication Date: 2020-01-14
TIANJIN ENEW ENVIRONMENTAL PROTECTION ENGCO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The acid leaching of sludge not only leaches aluminum ions into the solution, but also leaches nitrogen, phosphorus, iron, COD and a small amount of zinc into the solution. Hydrochloric acid and aluminum-containing sludge production method of polyaluminum chloride and gypsum series products" (patent number: 201610930742.3) and patent "a method of processing aluminum-containing sludge and preparing aluminum sulfate" (patent number: 201810373366.1), the leaching The extraction liquid is directly polymerized, and the quality of the flocculant product is not good

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Take the sludge from the municipal sewage plant, whose total aluminum content on dry basis is 13%, adjust its water content to 85%, add dilute sulfuric acid solution with a volume concentration of 20%, make the pH of the sludge solution 2, fully mix and react 0.5 h, fully reacted and added tap water 8 times of the sludge solution, and allowed to settle; after neutralizing the precipitated sludge, it was filtered, and the weight loss on a dry basis was determined to be 16%, the total aluminum content on a dry basis was 3.5%, and the extraction rate of aluminum 77.4%; Take out the supernatant of the precipitate, wherein the concentration of aluminum ions is 1700mg / L, add 10% NaOH solution to the solution, adjust the pH of the solution to 3, react for 1h, filter the precipitate after static settling, and then add it to the solution Add 10% NaOH solution, adjust the pH of the solution to 5, and react for 1 hour to obtain an aluminum-containing precipitate; wash the aluminum-...

Embodiment 2

[0044]Take the sludge from the municipal sewage plant, whose dry basis total aluminum content is 9%, adjust its water content to 95%, add dilute sulfuric acid solution with a volume concentration of 50%, make the pH of the sludge solution 1, and fully mix and react for 2 hours , fully reacted by adding 2 times the amount of tap water to the sludge solution, and allowed to settle; after neutralizing the precipitated sludge, it was filtered, and the weight loss on a dry basis was determined to be 14%, the total aluminum content on a dry basis was 1.7%, and the extraction rate of aluminum was 83.8% %; Take out the precipitation supernatant, wherein the aluminum ion concentration is 1200mg / L, add 10% CaO turbid solution to the solution, adjust the pH of the solution to 4, react for 1h, filter the precipitate after static settling, and then add it to the solution Add 10% CaO turbid solution, adjust the pH of the solution to 6, and react for 1 hour to obtain an aluminum-containing pr...

Embodiment 3

[0047] Take the sludge from the municipal sewage plant, whose dry basis total aluminum content is 15%, adjust its water content to 90%, add a dilute sulfuric acid solution with a volume concentration of 30%, so that the pH of the sludge solution is 1.5, and fully mix and react for 2 hours , fully reacted by adding 3 times the amount of tap water to the sludge solution, and allowed to settle; after neutralizing the precipitated sludge, it was filtered, and the weight loss on a dry basis was determined to be 21%, the total aluminum content on a dry basis was 2.7%, and the extraction rate of aluminum was 85.8% %; Take out the precipitation supernatant, wherein the aluminum ion concentration is 3300mg / L, add 10% NaOH solution to the solution, adjust the pH of the solution to 4, react for 1h, filter out the precipitate after static sedimentation, and then add to the solution 10% CaO turbid solution, adjust the pH of the solution to 5, and react for 1 hour to obtain an aluminum-conta...

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Abstract

The invention provides a preparation method of an aluminum-containing flocculant through extraction of aluminum from sludge. The preparation method comprises the steps: dissolving aluminum of the sludge by using dilute sulfuric acid, removing impurities which are brought in the obtained solution in the dissolution process through fractional precipitation, then precipitating high-purity aluminum salts, and performing aggregation so as to form the aluminum salt flocculant. Through the method, aluminum in the sludge can be recovered efficiently, the by-products which are carried from the sludge can be removed, and the prepared aluminum salt flocculant has a high effective concentration of aluminum and a good flocculation effect.

Description

technical field [0001] The invention relates to the field of sludge treatment, in particular to a method for extracting aluminum in sludge to prepare aluminum-containing flocculant. Background technique [0002] Aluminum salt is one of the most widely used flocculants in municipal sewage treatment plants in my country. Its main function is to remove phosphorus in sewage. These aluminum salts will eventually precipitate into municipal sludge, and the aluminum content in sludge is also relatively high. Around 10%. The main treatment methods of municipal sludge include sanitary landfill, incineration, anaerobic digestion, inorganic building materials, etc. Since municipal sludge contains a large amount of nitrogen, phosphorus, potassium and other nutrients and organic matter, its resource utilization and disposal are mostly land Utilization, the aluminum salt in the sludge cannot be utilized. The amount of aluminum salt flocculants used in sewage plants is about 30mg / L. At pre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/56C02F11/121C02F11/00
CPCC02F1/56C02F11/00C02F11/121C02F2209/08
Inventor 王学科刘静伟李彩然
Owner TIANJIN ENEW ENVIRONMENTAL PROTECTION ENGCO LTD