Solvent-out crystallization process of extracting aluminum oxide in coal ash by acid process

A technology for dissolving crystallization and alumina, applied in alumina/aluminum hydroxide, chemical industry, chlorine/hydrogen chloride, etc., can solve the problems of equipment corrosion and high investment cost, reduce equipment corrosion, reduce system investment cost, reduce The effect of energy consumption

Active Publication Date: 2017-08-04
SHIJIAZHUANG GONGDA CHEM EQUIP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The process has the advantages of short process, wide process technology conditions, recyclable utilization, relatively low raw material consumption, and low alumina production cost, but it also has the disadvantages of serious corrosion of equipment and high investment costs, so an adaptive process is required Improve

Method used

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  • Solvent-out crystallization process of extracting aluminum oxide in coal ash by acid process
  • Solvent-out crystallization process of extracting aluminum oxide in coal ash by acid process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Such as figure 1 As shown, a dissolution and crystallization process for extracting alumina in fly ash by acid method, the treatment of HCl-containing high-temperature roasting tail gas, the recovery and utilization of HCl gas, the recovery and utilization of AlCl 3 The three processes of solution evaporation and concentration are organically coupled, and the specific steps are as follows:

[0027] Step A. Pre-dry the crystalline AlCl from the crystallization section with the HCl-containing high-temperature roasting tail gas (temperature about 150-400°C) from the high-temperature roasting unit 3 ;

[0028] Step B, then use the remaining sensible heat (temperature is about 100°C) and unsaturated moisture carrying capacity of the HCl-containing high-temperature roasting tail gas to pre-concentrate the refined AlCl 3 The solution was re-concentrated to near saturation;

[0029] Step C, then the high-heat HCl-containing wet tail gas (temperature is about 70-80 ° C) is us...

Embodiment 2

[0038] The difference between this embodiment and embodiment 1 is: as figure 2 As shown, the adaptive selection is carried out according to the different composition ratios of HCl-containing high-temperature roasting tail gas, and the order of step B and step C is changed. The specific process is as follows:

[0039] Step A, firstly use HCl-containing high-temperature roasting tail gas to pre-dry the crystalline AlCl from the crystallization section 3 crystal;

[0040] Step B, then use the remaining sensible heat and unsaturated moisture carrying capacity of the HCl-containing high-temperature roasting tail gas to refine AlCl 3 The solution is pre-concentrated;

[0041]Step C, then the high-heat HCl-containing tail gas is used to carry the wet tail gas to the pre-concentrated refined AlCl 3 The solution was re-concentrated to near saturation;

[0042] Step D, then send the HCl-containing saturated tail gas that has been cooled and dehumidified to the crystallization secti...

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Abstract

The invention discloses a solvent-out crystallization process of extracting aluminum oxide in coal ash by an acid process and belongs to the technical field of refined chemical comprehensive utilization of coal ash. The process comprises the following steps: pre-drying crystallized aluminum chloride in a crystallizing section with HCl-containing high-temperature roasted tail gas; then concentrating a refined aluminum chloride solution to be nearly saturated by means of residual sensible heat and an unsaturated moisture-carrying ability; then pre-concentrating the refined aluminum chloride solution with high heat moisture-carrying tail gas; then feeding the cooled and dehumidified saturated tail gas to the crystallization section to absorb HCl gas by the aluminum chloride solutions concentrated to be saturated twice to separate out crystallized aluminum oxide; and finally, performing centrifugal separation to obtain aluminum chloride hexahydrate and pre-drying the same and then performing roasting decomposition to obtain a metallurgical level aluminum oxide finished product. By refining the concentrated crystallized aluminum chloride and thermocouple utilizing high-temperature tail gas of the roasting unit in the process course, the hydrogen chloride containing tail gas is comprehensively recycled, so that the energy consumption of an evaporation and concentration unit is further reduced.

Description

technical field [0001] The invention relates to a dissolution and crystallization process for extracting alumina in fly ash by an acid method, which belongs to the technical field of fine chemical comprehensive utilization of fly ash, and in particular to a dissolution and crystallization process for extracting alumina in fly ash by one-step acid dissolution . Background technique [0002] As my country's power generation increases year by year, the amount of fly ash produced is also increasing dramatically. In recent years, the comprehensive utilization of high-alumina fly ash and the technology of extracting alumina from fly ash have made great progress, and a large number of production process patent technologies have also been produced. The methods of extracting alumina from fly ash can be roughly divided into alkali method, acid-base combined method and acid method. Among them, the one-step acid-dissolution process mainly involves mixing and reacting fly ash with hydro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01B7/01
CPCC01B7/01C01F7/02Y02P20/10Y02P20/129
Inventor 张继军
Owner SHIJIAZHUANG GONGDA CHEM EQUIP
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