Extracting Alumina from Coal Fly Ash with Ammonium Sulfate Sintering Process

The effects of MgO and temperature on the properties and microstructure of mullite ceramics synthesized from high-aluminium coal fly ash and bauxite are investigated in this paper. The results show that when the batch containing 4 wt% MgO is heated from 1100 °C to 1500 °C, the bulk density and flexural strength increase obviously with the sintering temperature rising, mullite ceramics with flexural strength as high as 169 MPa can be obtained at 1500 °C with the addition of 2 wt% MgO. According to the XRD results, the corundum, cordierite and cristobalite phases disappear completely upon 1400 °C, it indicates that MgO addition may effectively promote sintering process. The results of SEM indicate that the prepared ceramics mainly exist in the shape of long parallelepipeds with the aspect ratio of about 7-10.

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Alkali desilicated coal fly ash as substitute of bauxite in lime-soda sintering process for aluminum production

Transactions of Nonferrous Metals Society of China ◽

10.1016/s1003-6326(10)60034-9 ◽

2010 ◽

Vol 20 ◽

pp. s169-s175 ◽

Cited By ~ 65

Author(s):

Guang-hui BAI ◽

Wei TENG ◽

Xiang-gang WANG ◽

Jin-guo QIN ◽

Peng XU ◽

...

Keyword(s):

Fly Ash ◽

Coal Fly Ash ◽

Aluminum Production ◽

Sintering Process

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Preparation of α-Alumina from Coal Fly Ash by Sintering with Sulfuric Acid

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.113-116.2039 ◽

2010 ◽

Vol 113-116 ◽

pp. 2039-2044 ◽

Cited By ~ 4

Author(s):

Wen Ning Mu ◽

Yu Chun Zhai

Keyword(s):

Sulfuric Acid ◽

Fly Ash ◽

Coal Fly Ash ◽

Acid Leaching ◽

National Standards ◽

Sintering Process ◽

Optimal Parameters ◽

Mass Ratio ◽

Sulfuric Acid Leaching ◽

Sintering Time

A technology was studied to prepare -alumina from fly ash, and the integrated process flow including sintering with sulfuric acid, leaching, recrystallization, calcination was established in this paper. The influences including the particle size of fly ash, sintering temperature, sintering time and the mass ratio of sulfuric acid to fly ash on the extraction ratio of alumina were investigated and discussed during sintering process, and the optimal parameters were determined. The product of -alumina was examined by chemical analysis, XRD and SEM, and the results show that α-alumina reach the national standards.

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Thermodynamic Analysis in Sintering Reaction of Coal Fly Ash with Alkali

Materials Science Forum ◽

10.4028/www.scientific.net/msf.809-810.895 ◽

2014 ◽

Vol 809-810 ◽

pp. 895-900

Author(s):

Si Qiong Li ◽

Jie Chen

Keyword(s):

Fly Ash ◽

Thermodynamic Analysis ◽

Calcium Oxide ◽

Sodium Carbonate ◽

Coal Fly Ash ◽

Sintering Process ◽

Experiment Study ◽

Sintering Additives ◽

Sintering Additive ◽

Alkali Salts

With sodium carbonate and calcium oxide as sintering additives, through the thermodynamic analysis and sintering experiment, study the thermodynamic behavior of fly ash with both in the sintering process; the sintering products were analyzed by XRD. The research results show that sodium carbonate as sintering additive fly ash thermal decomposition of the main phase of nepheline (NaAlSiO4), calcium oxide as sintering additives, and fly ash sintered products mainly 12CaO·7Al2O3、2CaO·Al2O3·SiO2 and 2CaO·SiO2 etc., And the temperature of the above substances generated is very favorable, fly ash and calcium oxide sintered at high temperature. Through sintering can effectively decompose the fly ash of quartz and mullite, soluble in acid or alkali salts, lay the foundation for the extraction of aluminum and silicon material from fly ash.

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Effect of Temperature on Phase Composition of Sintering Coal Fly Ash with Ammonium Sulfate

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.448-453.3088 ◽

2013 ◽

Vol 448-453 ◽

pp. 3088-3092

Author(s):

Yu Sheng Wu ◽

Jiao Chen ◽

Lai Shi Li ◽

Ming Chun Li ◽

Ping Xu ◽

...

Keyword(s):

Phase Composition ◽

Fly Ash ◽

Ammonium Sulfate ◽

Extraction Efficiency ◽

Sintering Temperature ◽

Coal Fly Ash ◽

Effect Of Temperature ◽

New Processing ◽

Increasing Temperature ◽

Rising Time

The new processing technology of extraction alumina by sintering coal fly ash with ammonium sulfate was studied. The phase evolutions of the sintered coal fly ash in different temperature schemes were characterized by X-ray diffractometry. The alumina extraction efficiency of sintered coal fly ash obtained from different sintering temperature schemes had also been investigated. The results show that the sintering temperature and holding time markedly influence the phase composition and alumina extraction efficiency of sintered coal fly ash, while the temperature rising time has little influence on it. The optimal temperature scheme for sintering coal fly ash with ammonium sulfate has been eventually confirmed that increasing temperature from ambient temperature to 400 °C for 1 h and heating for 3 h in air and the alumina extraction efficiency from as-sintered coal fly ash can reach 85.6%.

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