Method for producing ultrawhite aluminum hydroxide and by-products from high-alumina fly ash by using high-temperature alkaline leaching

A high-alumina fly ash and aluminum hydroxide technology, applied in the field of metallurgy, can solve problems such as difficulty in realizing large-scale industrial production, large alkali consumption, and large discharge of silicon-calcium slag, so as to improve comprehensive utilization value and reduce energy consumption. consumption effect

Active Publication Date: 2013-06-26
NORTHEASTERN UNIV ENG & RES INST CO LTD
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Problems solved by technology

Among them, the alkali method includes limestone sintering method and soda lime sintering method. The traditional limestone sintering method uses fly ash as raw material to produce alumina by limestone sintering method. The main steps include: raw material preparation and pulverization, alumina alkali Liquid leaching, liquid-solid separation, carbon content of alumina solution, Bayer dissolution, seed separation, aluminum hydroxide separation and roasting, and cement clinker calcination, etc. Limestone sintering method has high energy consumption (sintering temperature 1300-1400 ℃) , the one-time resource consumption is large (about 2.3 tons of limestone resources are consumed per 1 ton of fly ash), and the discharge of silicon-calcium slag is large (about 3.2 t of silicon-calcium slag is produced per 1 ton of fly ash); pre-desilication + soda lime The sintering method is a technology independently developed by Inner Mongolia Datang International Renewable Resources Development Co., Ltd. to use high-alumina fly ash to extract alumina and co-produce silicon products such as white carbon black and active calcium silicate. Silicon technology, improve the ratio of aluminum to silicon, reduce the amount of slagging, mainly including: pre-desiliconization, white carbon black (active calcium silicate) preparation, raw slurry preparation, clinker firing, first and second stage desiliconization at atmospheric pressure, carbon black sorting, sorting and roasting; the improved soda-lime sintering method is a technology independently developed by the China University of Geosciences (Beijing) Mineral Materials National Profess

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  • Method for producing ultrawhite aluminum hydroxide and by-products from high-alumina fly ash by using high-temperature alkaline leaching

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Experimental program
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Effect test

Embodiment 1

[0020] (1) Ball mill the high-aluminum fly ash to a particle size below 200 mesh, mix it evenly with the circulating NaOH solution and tricalcium aluminate washing solution, and the Al in the mixed solution 2 0 3 The concentration is 13~14g / L, αk=30, desiliconization at 80℃ for 1.0h ，Obtain one-stage desiliconization liquid and one-stage desiliconization slag, and then carry out two-stage medium-pressure desiliconization on the first-stage desiliconization slag under the conditions of 160°C and 0.27MPa for 0.8h to obtain two-stage desiliconization slag and two-stage desiliconization liquid. The first-stage desiliconization liquid is mixed with the second-stage desiliconization liquid to obtain a mixed liquid, and milk of lime is added to the mixed liquid for causticizing reaction. The amount of milk of lime added is 38% of the volume of the desiliconized liquid after mixing to obtain a wollastonite slurry. The wollastonite slurry is separated and washed to obtain solid wollas...

Embodiment 2

[0028] (1) Ball mill the high-aluminum fly ash to a particle size below 200 mesh, mix it evenly with the circulating NaOH solution and tricalcium aluminate washing solution, and the Al in the mixed solution 2 0 3 The concentration is 13~14g / L, αk=30, desiliconization at 90℃ for 0.8h ， Obtain one-stage desiliconization liquid and one-stage desiliconization slag, and then carry out two-stage medium-pressure desiliconization on the first-stage desiliconization slag under the condition of 130°C and 0.62MPa for 0.5h to obtain two-stage desiliconization slag and two-stage desiliconization liquid, The first-stage desiliconization liquid is mixed with the second-stage desiliconization liquid to obtain a mixed liquid, and milk of lime is added to the mixed liquid for causticizing reaction. The amount of milk of lime added is 40% of the volume of the desiliconized liquid after mixing to obtain a wollastonite slurry. The wollastonite slurry is separated and washed to obtain solid wollas...

Embodiment 3

[0036] (1) Ball mill the high-aluminum fly ash to a particle size below 200 mesh, mix it evenly with the circulating NaOH solution and tricalcium aluminate washing solution, and the Al in the mixed solution 2 0 3 Concentration is 13~14g / L, αk=30, Al in the mixture 2 o 3 The concentration is 13~14g / L, αk=30, desiliconization at 105℃ for 0.5h ， Obtain one-stage desiliconization liquid and one-stage desiliconization slag, then carry out second-stage medium-pressure desiliconization on the first-stage desiliconization slag under the condition of 150°C and 0.51MPa for 1.0h to obtain two-stage desiliconization slag and second-stage desiliconization liquid, The first-stage desiliconization liquid is mixed with the second-stage desiliconization liquid to obtain a mixed liquid, and milk of lime is added to the mixed liquid for causticizing reaction. The amount of milk of lime added is 42% of the volume of the desiliconized liquid after mixing to obtain a wollastonite slurry. The wol...

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Abstract

The invention belongs to the technical field of metallurgy and in particular relates to a method for producing ultrawhite aluminum hydroxide and by-products from high-alumina fly ash by using high-temperature alkaline leaching. The method comprises the following steps of: carrying out two-stage pre-desilicication on the high-alumina fly ash, and then carrying out leaching reaction for 1.5-2.5 hours at 230-280 DEG C to respectively produce the ultrawhite hydroxide as well as wollastonite and ferrugination hydrogarnet as by-products. According to the method, a high-temperature sintering process in which low alumina-silica ratio firing temperature is difficult to control in the process of extracting aluminum hydroxide from the high-alumina fly ash is avoided, the energy consumption is reduced, the comprehensive utilization value of the fly ash is improved, and meanwhile, products in each link can be recycled in each procedure; and an economic and effective technical approach is provided for preparation of the ultrawhite aluminum hydroxide and alumina from the high-alumina fly ash.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for producing ultra-white aluminum hydroxide and by-products by high-temperature alkali leaching of high-alumina fly ash. Background technique [0002] Fly ash is rich in resources, and the output is large and concentrated. Every time a power plant generates 1000Kwh of electricity, an average of 87kg of fly ash is produced. With the continuous increase in power demand, its emissions will increase year by year. It also pollutes the environment; at the same time, with the depletion of bauxite resources in my country and the world, extracting alumina from fly ash is in line with my country's industrial policy of developing circular economy and building a resource-saving and environment-friendly society , has become a focus of attention and research in related industries in recent years. [0003] Common methods for extracting alumina from high alumina fly ash i...

Claims

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Application Information

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IPC IPC(8): C01F7/02
Inventor 赵成明黎娜罗亚林
Owner NORTHEASTERN UNIV ENG & RES INST CO LTD
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