Method for processing fly ash

A treatment method, fly ash technology, applied in the field of acid-base combined method, can solve problems such as difficult to produce economic benefits, low resource utilization rate, secondary pollution, etc., and achieve high added value of products, no three waste pollution, and low technical risk Effect

Inactive Publication Date: 2015-03-25
GUIYANG AL-MG DESIGN & RES INST
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Most reported in the literature is the addition of co-solvents (such as NH 4 F and CaF), but the dissolution rate is still relatively low, only 35-45%, the resource utilization rate is low, and the fluorine element that pollutes the environment is added, causing secondary pollution.
In short, the current high-value utilization of fly ash only focuses on the extraction of aluminum, while ignoring the extraction of silicon, iron and other elements, it is difficult to produce economic benefits

Method used

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  • Method for processing fly ash

Examples

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Effect test

Embodiment 1

[0036] 1) Grind the high-alumina fly ash of a circulating fluidized bed in a certain place (see Table 1 for the chemical composition) to 200 mesh, and mix the ground fly ash and sodium carbonate by weight percentage fly ash: sodium carbonate = 1:2 Proportions were mixed and fired at 800°C for 1 hour. The sintered product is leached with water (the weight percentage of the sintered product and water is 1:100, and the water is ordinary tap water) at 80°C for 3 hours and then filtered, and the leaching solution is carbon dioxide at 90°C for 3 hours and then filtered to obtain Silica gel and aluminum hydroxide, and the filtrate is sodium carbonate solution, which is returned to the process for recycling after evaporation and concentration.

[0037]2) Neutralize the silica gel and aluminum hydroxide obtained in step (1) with 36% hydrochloric acid (5 tons of hydrochloric acid per ton of silica gel and aluminum hydroxide) at 80°C for 1 hour, then filter to obtain silica gel, and wash...

Embodiment 2

[0041] 1) Grind the high-alumina fly ash of a circulating fluidized bed in a certain place whose chemical composition is shown in Table 1 to 400 mesh, and mix the ground fly ash and sodium carbonate by weight percentage fly ash: sodium carbonate = 1:3 The ratio was mixed and baked at 1000°C for 3 hours. The sintered product is leached with water (the weight percentage of sintered product and water is 1:150, and the water is ordinary tap water) at 100°C for 5 hours and then filtered, and the leaching solution is carbon dioxide at 90°C for 5 hours and then filtered to obtain Silica gel and aluminum hydroxide, and the filtrate is sodium carbonate solution, which is returned to the process for recycling after evaporation and concentration.

[0042] 2) Neutralize the silica gel and aluminum hydroxide obtained in step 1) with 36% hydrochloric acid (6 tons of hydrochloric acid per ton of silica gel and aluminum hydroxide) at 100°C for 2 hours and then filter to obtain silica gel. Aft...

Embodiment 3

[0047] 1) Grind the high-aluminum fly ash (see Table 2 for the chemical composition) of a pulverized coal furnace in a certain place to 300 mesh, and mix the ground fly ash and sodium carbonate in a ratio of fly ash: sodium carbonate = 1:1 by weight Mixing was carried out and firing was carried out at 500° C. for 0.5 hours. The sintered product is leached with water (the weight percentage of sintered product and water is 1:50, and the water is ordinary tap water) at 60°C for 1 hour and then filtered, and the leaching solution is carbon dioxide at 80°C for 1 hour and then filtered to obtain Silica gel and aluminum hydroxide, and the filtrate is sodium carbonate solution, which is returned to the process for recycling after evaporation and concentration.

[0048] 2) Neutralize the silica gel and aluminum hydroxide obtained in step 1) with 25% hydrochloric acid (4 tons of hydrochloric acid per ton of silica gel and aluminum hydroxide) at 50°C for 0.5 hours and then filter to obta...

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Abstract

The invention relates to a method for processing fly ash, which comprises the following steps: adding sodium carbonate in the ground fly ash for roasting, then leaching by using water, leaching liquid carbon to obtain silica gel and aluminium hydroxide; neutralizing silica gel and aluminium hydroxide by hydrochloric acid, filtering to obtain the silica gel, processing and calcining to obtain white carbon black; performing evaporative concentration on the obtained aluminium chloride solution, crystallizing to obtain the aluminium chloride crystals, performing pyrolysis on the crystals to obtain initial alumina; and processing the initial alumina by a barer process to obtain the metallurgical-grade alumina and high iron slag, wherein the high iron slag can be a raw material for ironmaking. According to the invention, extraction for useful elements such as aluminium, silicon and iron in the fly ash can be realized, recovery rate can reach more than 90%, residue amount after extraction accounts for lower than 10% of mount of fly ash, carbon dioxide, acid and alkali required in the invention can be recovered and used, zero discharge can be realized during a whole technical process, and no secondary pollution can be generated on environment.

Description

technical field [0001] The invention belongs to the field of high-value utilization of fly ash, in particular to an acid-base combined method for extracting aluminum, silicon, iron and other useful elements from fly ash. Background technique [0002] In recent years, the rapid development of my country's coal power industry has brought about a sharp increase in the discharge of solid waste fly ash. By 2007, the annual discharge of fly ash in my country has exceeded 200 million tons, and it is still increasing year by year. , and the cumulative stockpiles exceed 2.5 billion tons. A large amount of fly ash not only occupies a large amount of land, but also causes serious pollution to soil, water resources and air. Therefore, the comprehensive utilization of fly ash has become a top priority. [0003] At present, fly ash has been used in many fields such as construction and construction. Although it is used in a large amount, its digestion is far behind the increase in emissio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01B33/12B09B3/00
Inventor 马家玉
Owner GUIYANG AL-MG DESIGN & RES INST
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