Method for recycling magnesium from heavy metal sludge to prepare magnesium hydroxide fire retardant

A technology of heavy metal sludge and magnesium hydroxide, applied in the direction of magnesium hydroxide, process efficiency improvement, etc., can solve the problems of environmental burden and resource waste, unreasonable utilization of magnesium resources, low purity of cobalt, nickel and manganese, etc., and achieves the recovery process. Reasonable and easy to implement, considerable economic value, and the effect of high recovery rate

Active Publication Date: 2017-02-01
JINGMEN GEM NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The sludge is rich in valuable metals such as cobalt, nickel, manganese, and magnesium. It is currently used for acid leaching to recycle precious metals such as cobalt, nickel, and manganese (as the raw material solution prepared by ternary battery materials). A large amount of magnesium resources produced in the acid leaching process are rich. Magnesium circulates in the system, magnesium does not have a suitable open circuit (made into product or efflux) so it is difficult to handle
Due to the lack of suitable treatment methods for magnesium resources, it has caused serious environmental burdens and waste of resources.
[0004] To sum up, in the current process of extracting heavy metal sludge, there is a large amount of magnesium in the leachate that is difficult to separate, and the purity of cobalt, nickel, manganese, etc. as raw materials for ternary batteries is low, and a large amount of magnesium resources in the leachate cannot be rationally utilized, resulting in waste of magnesium resources. question
Flame retardants have the disadvantages of high equipment requirements and high energy consumption

Method used

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  • Method for recycling magnesium from heavy metal sludge to prepare magnesium hydroxide fire retardant

Examples

Experimental program
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Effect test

Embodiment 1

[0027] A method for reclaiming magnesium from heavy metal sludge, comprising the following steps:

[0028] Pretreatment water washing: add heavy metal sludge to pure water according to the mass ratio of pure water to sludge dry matter 8:1, turn on the electric furnace to heat up, and adjust the pH to 7.0 with 0.4g / L dilute sulfuric acid aqueous solution while stirring (the temperature is finally stabilized at 80°C, pH=7.0 is measured at this temperature), continue to stir for 10 minutes, the obtained water residue mixture is dehydrated by plate and frame pressure filtration, and filtrate 1 and filter residue 1 are obtained; filter residue 1 is washed with hot water at 80-90°C, filtered and dehydrated 1 time, the filtrate 2 was obtained. The filtrate obtained by combining filtrate 1 and filtrate 2 is magnesium liquid. Magnesium in the magnesium solution accounts for more than 99% of the magnesium in the heavy metal sludge, the content of Ni is 0.5mg / L, Co, Mn, and Zn are not d...

Embodiment 2

[0030] A kind of method based on embodiment 1 reclaims magnesium from heavy metal sludge and prepares magnesium hydroxide flame retardant, comprises the following steps:

[0031] 1. Pretreatment water washing: add heavy metal sludge to pure water according to the mass ratio of pure water to sludge dry matter 8:1, turn on the electric furnace to heat up, and adjust the pH to 7.0 with 0.4g / L dilute sulfuric acid aqueous solution while stirring (the temperature is at the end Stable at 80°C, pH=7.0 is measured at this temperature), continue to stir for 10 minutes, the obtained water residue mixture is dehydrated by plate and frame pressure filtration, and filtrate 1 and filter residue 1 are obtained; filter residue 1 is washed with hot water at 80-90°C Filter and dehydrate once to obtain filtrate 2. The filtrate obtained by combining filtrate 1 and filtrate 2 is magnesium liquid. Magnesium in the magnesium solution accounts for more than 99% of the magnesium in the heavy metal sl...

Embodiment 3

[0040] A method for reclaiming magnesium from heavy metal sludge, comprising the following steps:

[0041] Pretreatment water washing: add heavy metal sludge to pure water according to the mass ratio of pure water to sludge dry matter 15:1, turn on the electric furnace to heat up, and adjust the pH to 8.0 with 0.6g / L dilute sulfuric acid aqueous solution while stirring (the temperature is finally stabilized at 85°C, pH=8.0 is measured at this temperature), continue to stir for 15 minutes, and dehydrate the water residue mixture through plate and frame pressure filtration to obtain filtrate 1 and filter residue 1; filter residue 1 is washed with hot water at 80-90°C, filtered and dehydrated 3 times to obtain the filtrate 2. The filtrate obtained by combining filtrate 1 and filtrate 2 is magnesium liquid. Magnesium in the magnesium solution accounts for more than 99% of the magnesium in the heavy metal sludge, the content of Ni is 0.6mg / L, Co, Mn, and Zn are not detected, and t...

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Abstract

The invention provides a method for recycling magnesium from heavy metal sludge. The method includes the following steps that the heavy metal sludge is added into pure water according to the mass ratio of the pure water to sludge dry matter being 8:1-15:1, and stirring is performed while heating is conducted; the mixture is heated to 80-85 DEG C and heat preservation is carried out; dilute sulphuric acid of 0.4g/L-0.6g/L is added in the heating and stirring processes until the pH is measured to be 7.0-8.0 at the temperature of 80-85 DEG C; stirring is continuously performed for 10-15min, so that a water-slag mixture is obtained, and filter liquor 1 is obtained through plate-frame pressure filtration dehydration; filter residues are washed with hot water, filtered and dehydrated for 1-3 times, and accordingly filter liquor 2 is obtained; and the filter liquor 1 and the filter liquor 2 are combined, and the obtained filter liquor is magnesium liquor. Based on the method, the invention further provides a method for recycling magnesium from heavy metal sludge to prepare magnesium hydroxide fire retardant. The method includes the following steps of pretreatment washing, alkaline liquor adding for magnesium settlement, surface modification, ageing, hydro-thermal treatment, dehydration, washing and drying. In the process of the invention, the one-time recovery rate of magnesium is increased while the precious metal cobalt-nickel recovery rate and purity of flame-retardant magnesium hydroxide coarse products are guaranteed.

Description

technical field [0001] The invention belongs to the technical field of resource recycling and hydrometallurgy, and more specifically relates to a method for recovering and extracting magnesium hydroxide flame retardant from heavy metal sludge. Background technique [0002] The industrial production of magnesium hydroxide mainly has the following five methods: (1) reacting limestone and brine to produce magnesium hydroxide; (2) reacting sodium hydroxide with brine and halogen blocks to produce magnesium hydroxide; (3) using calcined Magnesite, dolomite and brine, brine block reaction to produce magnesium hydroxide; (4) use MgO to hydrate to generate magnesium hydroxide, where MgO must be a lightly burned product to ensure the activity of hydration; (5) use ammonia and brine, Halogen block reaction to produce magnesium hydroxide. In the later stage, surface modifiers are used to modify magnesium hydroxide, and traditional methods such as seed crystal method and hydrothermal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C01F5/22C09K21/02
CPCC01F5/22C01P2004/20C01P2004/51C01P2004/61C01P2004/62C01P2006/12C01P2006/80C09K21/02C22B7/00C22B7/006Y02P10/20
Inventor 许开华张云河盛广宏
Owner JINGMEN GEM NEW MATERIAL
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