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Method for comprehensively utilizing fly ash

A technology of fly ash and alumina, applied in the direction of chemical instruments and methods, aluminum compounds, process efficiency improvement, etc., can solve problems such as equipment corrosion, high iron impurity content, high pressure, etc.

Pending Publication Date: 2021-11-02
眉山顺应循环再生资源有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Alkaline recovery process is mature, but the process is long and the recovery cost is high
The acid method currently includes the hydrochloric acid method and the sulfuric acid method. The iron content in fly ash is relatively high. In the existing acid recovery process, the acid directly leaches the fly ash, and almost all the iron in the fly ash enters the leaching solution. The acid consumption is high and the leaching High cost, high iron impurity content in leach solution, high cost of impurity removal
In addition, during the hydrochloric acid leaching process, the acid gas of hydrogen chloride is volatile and the equipment is severely corroded. In particular, the pressurized leaching equipment requires special materials and high investment costs. Disadvantages such as high security requirements

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  • Method for comprehensively utilizing fly ash

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] (1) Add water to the fly ash and grind it to less than 100 meshes to obtain ore pulp. The mass percentage concentration of the ore pulp is 15%. Magnetic filter residue, the magnetic field strength of magnetic separation is 3000Gs, the mass percentage of chemical element composition of non-magnetic filter residue includes: Fe is 2.33%; Al is 19.83%; Si is 22.27%; Ca is 2.18%; Mg is 0.37%; Ga is 120g / t.

[0035] (2) subjecting the non-magnetic material filter residue to nitric acid pressure leaching reaction, and filtering to obtain filtrate and silica residue. The nitric acid pressure leaching conditions include: the liquid-solid ratio of the nonmagnetic filter residue to water is 4:1, the mass percentage concentration of nitric acid is 20%, and the addition of nitric acid is 1% of aluminum in the nonmagnetic filter residue. The acid consumption is 1.1 times the theoretical value, the leaching temperature is 120°C, the stirring speed is 50rpm, the leaching time is 1h, a...

Embodiment 2

[0041] (1) Add water to the fly ash and grind it to below 100 orders through ball milling to obtain the ore pulp. The mass percentage concentration of the ore pulp is 30%. Carbon concentrate is used to prepare refined carbon powder, and then separated by magnetic separation to obtain non-magnetic filter residue. The magnetic field strength of magnetic separation is 8000Gs, and the mass fraction of chemical elements of non-magnetic filter residue includes: Fe is 2.41%; Al is 22.64%; Si 21.25%; Ca 3.82%; Mg 0.38%; Ga 100g / t.

[0042](2) subjecting the non-magnetic material filter residue to nitric acid pressure leaching reaction, and filtering to obtain filtrate and silica residue. The nitric acid pressure leaching conditions include: the liquid-solid ratio of the nonmagnetic filter residue to water is 3:1, the mass percent concentration of nitric acid is 45%, and the addition of nitric acid is 1% of aluminum in the nonmagnetic filter residue. The acid consumption is 1.5 times ...

Embodiment 3

[0047] (1) Add water to the fly ash and grind it to below 100 meshes by ball milling to obtain the pulp, which is floated to remove carbon to obtain the fly ash tailings slurry. The mass percentage concentration of the pulp is 45%, and then separated by magnetic separation to obtain Non-magnetic filter residue, the magnetic field strength of magnetic separation is 12000Gs, the mass fraction of the chemical element composition of the non-magnetic filter residue includes: Fe is 2.11%; Al is 25.17%; Si is 18.55%; Ca is 3.59%; Mg is 0.32% ; Ga is 135g / t.

[0048] (2) subjecting the non-magnetic material filter residue to nitric acid pressure leaching reaction, and filtering to obtain filtrate and silica residue. The nitric acid pressure leaching conditions include: the liquid-solid ratio of the nonmagnetic filter residue to water is 5:1, the mass percentage concentration of nitric acid is 60%, and the addition of nitric acid is 1% of aluminum in the nonmagnetic filter residue. Th...

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Abstract

The invention discloses a method for comprehensively utilizing fly ash, and belongs to the technical field of fly ash resource utilization. The method comprises the steps of firstly, adding water into fly ash, grinding to obtain ore pulp, and separating out carbon through flotation to obtain fly ash tailing pulp; performing magnetic separation on the tailing pulp to obtain magnetic material iron ore concentrate containing a large amount of iron, and treating non-magnetic materials by adopting a nitric acid leaching process; adding hydrogen peroxide into the leachate under an acidic condition to oxidize ferrous iron, generating Fe (OH) 3 precipitate, separating out, filtering, and extracting rare metals such as scandium, gallium, germanium and gallium from filtrate through an extraction process; and evaporating and concentrating the purified aluminum nitrate solution to obtain aluminum nitrate crystals, and obtaining aluminum oxide after calcination, wherein nitric oxide gas generated by calcination passes through a nitric acid absorption device to regenerate nitric acid, and the nitric acid is returned for leaching and recycling. The acid in the method does not need to be used for leaching a large amount of iron, and the method has the advantages of being low in acid consumption, low in impurity content of the leachate, low in impurity removal cost, capable of regenerating and recycling the leaching agent nitric acid, low in equipment requirement, simple in process and the like.

Description

technical field [0001] The invention belongs to the technical field of resource utilization of fly ash, and in particular relates to a method for producing alumina by comprehensive utilization of fly ash. Background technique [0002] At present, my country's thermal power generation and northern heating plants still use coal, which produces a large amount of fly ash. Fly ash is widely used in construction, building materials, metallurgy, chemical industry, environmental protection, backfill, high-performance ceramic materials and other industrial fields, and can also be used in agricultural fields such as soil improvement and land reclamation. Fly ash contains a large amount of rare metals such as alumina, silicon dioxide, iron, gallium, germanium, etc., but my country's aluminum resources are very scarce, so the resource utilization of fly ash has important research significance and broad market prospects. [0003] The methods of extracting alumina from fly ash can be div...

Claims

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Application Information

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IPC IPC(8): C01F7/30C01F7/66C01B33/12C22B59/00C22B58/00C22B41/00C22B3/22C22B3/44
CPCC01F7/308C01F7/66C01B33/12C22B59/00C22B58/00C22B41/00C22B3/22C22B3/44Y02P10/20
Inventor 王成彦赵林但勇马保中陈永强赵澎金长浩高波邓婉琴赵顶
Owner 眉山顺应循环再生资源有限公司