lime sintering for alumina production process

Lime-sinter process for production of alumina from fly

The lime-soda sinter process involves sintering of the fly ash and alkaline oxides at 1100-1300/sup 0/C to break the alumina-silica bonds and form soluble aluminate compounds and insoluble calcium silicates.

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An Improved Lime Sinter Process to Produce Al2O3

Low-grade bauxites and non-bauxite resources are widely distributed, which are suitable to extract alumina by the lime sinter process. The application of the lime sinter process is restricted by the high consumption of calcium, the large amount of slag and the poor alumina leaching property of clinkers. An improved lime sinter process based on the dry-sintering is proposed by adding Na 2 O

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Sintering kinetics and alumina yield in lime-soda

An investigation of the application of the lime-soda sinter process to alumina extraction from coal wastes has been carried out. In the sintering stage, the optimal operating conditions have been obtained for the highest yield of alumina. The kinetics of sodium aluminate formation have also been studied in the sintering

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New developments in the lime-soda sinter process for ...

A further investigation of the lime-soda sinter process has resulted in unique correlations between sinter composition and yield of alumina for fly ashes from both bituminous and subbituminous coals.

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SUSTAINABILITY IN ALUMINA PRODUCTION FROM

2017-12-4  lime is added to the sinter to form insoluble calcium silicate compounds. SUSTAINABILITY IN ALUMINA PRODUCTION The Bayer process and Pedersen process were invented long time ago. The Bayer process is the dominant commercial process at present and more than 95% of alumina

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Minerals Free Full-Text Sintering Optimisation and ...

Soda sintering or lime-soda sintering process, began from Louis Le Chatelier’s work in 1855 in obtaining aluminum hydroxide (Al (OH) 3) from sintering bauxite with soda at around 1000 °C which forms a leachable sodium aluminate species [ 23 ].

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A DOCUMENTARY STUDY ON ALUMINA EXTRACTION

2009-12-18  1. PROCESSES INVOLVING SINTERING pages 1.1. Lime sinter process applied to nephelines 4 111. Grinding and mixing 4 112. Sintering 4 113. Leaching 7 114. Desilicification 9 115. Carbonation 17 116. Cement production 19 117. Economic evaluation 21 1.2. The lime_soda sinter process 25 1.3. The lime sinter processes (self disintegration processes ...

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Low-Temperature Sintering of Alumina with Liquid

2019-2-4  forming additives to alumina resulted in a sintered density of >99% in 1 h at a temperature as low as 1070°C for a commercial high-purity alumina powder at a total dopant level of 2 mol%. The additives were 0.9% CuO + 0.9% TiOz + 0.1% B203 + 0.1% MgO. At higher temperatures or after prolonged sintering, the doped alumina ceramic de-

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The Optimization of Sintering Process for Alumina ...

The objective of paper is to optimize the variables of the sintering process with the six sigma philosophy. The impact of sintering temperature, Ca ratio, Na ratio and reaction time on the alumina reaching rate were primarily studied. In the research, a novel method was adopted to efficiently recover alumina and silica from high-alumina fly ash, and the response surface methodology of six ...

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Alumina : sintering and optical properties

development of sintered alumina as insulators for spark plugs. The electrical con­ ductivity is very sensitive to the purity of the oxide. Mechanically, alumina possesses great hardness, resistan~e to abrasive wear and dimensional stability. The strength properties of ~i!1tered alumina are strongly

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New developments in the lime-soda sinter process for ...

The efficiency of alumina recovery from coal fly ash by the lime-sinter process is improved by the addition of a small amount of coal cleaning refuse. Approximately 5.0 wt % refuse increases alumina recovery from 55% to 90% for subbituminous coal ashes and reduces the required sintering temperature from 1380 to 1200/sup 0/C. Mixtures of fly ash ...

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Sintering kinetics and alumina yield in lime-soda

An investigation of the application of the lime-soda sinter process to alumina extraction from coal wastes has been carried out. In the sintering stage, the optimal operating conditions have been obtained for the highest yield of alumina. The kinetics of sodium aluminate formation have also been studied in the sintering stage. The sinter mixes have been fired isothermally in air in the ...

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EXTRACTION OF ALUMINA FROM IRAQI COLORED

of sintering temperature and time, concentration of sodium carbonate solution, leaching time and sintered powder to sodium carbonate solution were studieratio d. About 85% of the alumina in the claystone was extracted at the optimumconditions. The alumina obtained in this method assaying 98% Al 2O 3, 1.45% SiO 2, 0.04% Fe 2O

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ARTICLE: Addressing the Challenge of Bauxite Residue ...

2019-3-11  A lime sintering process for production of alumina from boehmite and diaspore bauxites was developed for producing alumina from low grade bauxite in China and Russia. The process involves a pyro-metallurgical sinter approach, which produces aluminum while ”locking up” the silica as clinker, thus preventing it from contaminating the alumina.

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A DOCUMENTARY STUDY ON ALUMINA EXTRACTION

2009-12-18  1. PROCESSES INVOLVING SINTERING pages 1.1. Lime sinter process applied to nephelines 4 111. Grinding and mixing 4 112. Sintering 4 113. Leaching 7 114. Desilicification 9 115. Carbonation 17 116. Cement production 19 117. Economic evaluation 21 1.2. The lime_soda sinter process 25 1.3. The lime sinter processes (self disintegration processes ...

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Optimization of Sintering Process of Alumina Ceramics ...

2021-6-14  The solid-state sintering presents the third step in ceramics production. For alumina ceramic, solid-state sintering involves densifying a green body into a dense solid object at a high temperature above 1500–1800 C without melting (the melting point of alumina is 2050 C). Sintering to full density can be achieved at atmospheric pressure ...

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Low-Temperature Sintering of Alumina with Liquid

2019-2-4  optimal sintering time since longer time did not increase the density much. At 12OO0C, the sintering kinetics were so fast that a 99.1% density was reached in 15 min. However, the higher sintering temperature did not result in higher densities for sintering time longer than 1 h. The microstructure of a doped alumina (process B) sin-

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The Optimization of Sintering Process for Alumina ...

The objective of paper is to optimize the variables of the sintering process with the six sigma philosophy. The impact of sintering temperature, Ca ratio, Na ratio and reaction time on the alumina reaching rate were primarily studied. In the research, a novel method was adopted to efficiently recover alumina and silica from high-alumina fly ash, and the response surface methodology of six ...

More

Alumina : sintering and optical properties

were developed. A complication in the study of the sintering of alumina is the important role th~t impurilies i.e. not intentionally added ~dditives rMy play. It is very diftkult to prepare alumina on a largo soale with impurities in the ppm range, and many sintering studies have been carried Ollt with impure powders, making the

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Improved Sintering Procedures for Aluminum P/M

Abstract. This paper discusses sintering practices for the production of aluminum P/M parts in nitrogen and dissociated ammonia and in vacuum. The influence of sintering atmosphere, dew point and temperature on the mechanical properties and dimensions

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Sintering kinetics and alumina yield in lime-soda

An investigation of the application of the lime-soda sinter process to alumina extraction from coal wastes has been carried out. In the sintering stage, the optimal operating conditions have been obtained for the highest yield of alumina. The kinetics of sodium aluminate formation have also been studied in the sintering stage. The sinter mixes have been fired isothermally in air in the ...

More

EXTRACTION OF ALUMINA FROM IRAQI COLORED

of sintering temperature and time, concentration of sodium carbonate solution, leaching time and sintered powder to sodium carbonate solution were studieratio d. About 85% of the alumina in the claystone was extracted at the optimumconditions. The alumina obtained in this method assaying 98% Al 2O 3, 1.45% SiO 2, 0.04% Fe 2O

More

A DOCUMENTARY STUDY ON ALUMINA EXTRACTION

2009-12-18  1. PROCESSES INVOLVING SINTERING pages 1.1. Lime sinter process applied to nephelines 4 111. Grinding and mixing 4 112. Sintering 4 113. Leaching 7 114. Desilicification 9 115. Carbonation 17 116. Cement production 19 117. Economic evaluation 21 1.2. The lime_soda sinter process 25 1.3. The lime sinter processes (self disintegration processes ...

More

AA25 - Process Innovation and Technology Progress of

2020-12-21  The process is complex. Soda-Lime Sintering process unlimited High alumina recovery, low alkali consumption and high whiteness; High carbon decomposition rate; Red mud has hydraulic properties. Energy consumption is on the high side. 3. Innovation and Technical Progress of New Series Process for Alumina Production

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Optimization of Sintering Process of Alumina Ceramics ...

2021-6-14  The solid-state sintering presents the third step in ceramics production. For alumina ceramic, solid-state sintering involves densifying a green body into a dense solid object at a high temperature above 1500–1800 C without melting (the melting point of alumina is 2050 C). Sintering to full density can be achieved at atmospheric pressure ...

More

AA23 - Preparation of Metallurgical Grade Alumina from ...

2020-12-21  Many authors have tried to extract alumina from fly ash using different techniques such as lime stone sintering [4], [5] soda lime sintering [6], calsinter process [7], [8] ammonium sulphate sintering process [9] and acid leaching processes [10], [11]. However, this process

More

Alumina : sintering and optical properties

were developed. A complication in the study of the sintering of alumina is the important role th~t impurilies i.e. not intentionally added ~dditives rMy play. It is very diftkult to prepare alumina on a largo soale with impurities in the ppm range, and many sintering studies have been carried Ollt with impure powders, making the

More

The Optimization of Sintering Process for Alumina ...

The objective of paper is to optimize the variables of the sintering process with the six sigma philosophy. The impact of sintering temperature, Ca ratio, Na ratio and reaction time on the alumina reaching rate were primarily studied. In the research, a novel method was adopted to efficiently recover alumina and silica from high-alumina fly ash, and the response surface methodology of six ...

More

Ceramics: Sintering and Microstructure

2018-8-23  Usually this is done by a sintering process ... For example during the production of ceramic layers, the porosity is not always ... (e.g. 3987 g/cm3 for alpha alumina) and on the closed pore volume (Vf) with essentially zero density (equation (4)). This means that the volume of the closed pores can be

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Pressing And Sintering Of Powder Parts -

2017-9-10  Sintering temperature is typically .7 to .9 of the powder's melting point. Sintering time is dependent on manufacturing process factors and material. Tungsten, for example, is sintered for a relatively long time. Standard industrial powder sintering

More

A DOCUMENTARY STUDY ON ALUMINA EXTRACTION

2009-12-18  1. PROCESSES INVOLVING SINTERING pages 1.1. Lime sinter process applied to nephelines 4 111. Grinding and mixing 4 112. Sintering 4 113. Leaching 7 114. Desilicification 9 115. Carbonation 17 116. Cement production 19 117. Economic evaluation 21 1.2. The lime_soda sinter process 25 1.3. The lime sinter processes (self disintegration processes ...

More

AA25 - Process Innovation and Technology Progress of

2020-12-21  The process is complex. Soda-Lime Sintering process unlimited High alumina recovery, low alkali consumption and high whiteness; High carbon decomposition rate; Red mud has hydraulic properties. Energy consumption is on the high side. 3. Innovation and Technical Progress of New Series Process for Alumina Production

More

AA23 - Preparation of Metallurgical Grade Alumina from ...

2020-12-21  Many authors have tried to extract alumina from fly ash using different techniques such as lime stone sintering [4], [5] soda lime sintering [6], calsinter process [7], [8] ammonium sulphate sintering process [9] and acid leaching processes [10], [11]. However, this process

More

Optimization of Sintering Process of Alumina Ceramics ...

2021-6-14  The solid-state sintering presents the third step in ceramics production. For alumina ceramic, solid-state sintering involves densifying a green body into a dense solid object at a high temperature above 1500–1800 C without melting (the melting point of alumina is 2050 C). Sintering to full density can be achieved at atmospheric pressure ...

More

Zhang Baiyong, SAMI The Challenging and Solutions for

realistic for technical reconstructing and production organization of alumina refineries with both sintering system and Bayer system. October 2012 3 The fly ash resource and its extracting process in china 3.1 Overview of fly ash resource 3.2 Lime stone sintering process 3.3 Soda lime sintering process 3.4 Sulphuric acid process 3.5 Alkali and ...

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EXTRACTION OF ALUMINA FROM BAUXITE RESIDUE FOR

(40% from world production) [Sharif, 2005]. Research on extraction of alumina (Al2O3) from West Kalimantan bauxite residue was done by soda-lime sintering process that consists of sin-tering to the red mud with soda-lime at 800-1200 OC resulting sintered sodium aluminate solution (2NaAlO2). Separation of sodium aluminate solu-

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Ceramics: Sintering and Microstructure

2018-8-23  Usually this is done by a sintering process ... For example during the production of ceramic layers, the porosity is not always ... (e.g. 3987 g/cm3 for alpha alumina) and on the closed pore volume (Vf) with essentially zero density (equation (4)). This means that the volume of the closed pores can be

More

Advanced Ceramics Manufacturing Processes

During sintering the ceramic is heated to below its melting point. At high temperatures the fine ceramic powders undergo several changes from particle rearrangement to grain growth and finally pore elimination. For ceramics such as alumina and zirconia this process is called solid–state sintering and involves material transport by diffusion.

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Optimization of the Mixture Design for Alumina Sintering ...

To address the uncertainty of the ingredients in the process of the mixture design of alumina sintering,L-R fuzzy numbers were introduced in an optimization model for the mixture design.Based on the properties of the ɑ-cuting set of fuzzy number and the ...

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Pressing And Sintering Of Powder Parts -

2017-9-10  Sintering temperature is typically .7 to .9 of the powder's melting point. Sintering time is dependent on manufacturing process factors and material. Tungsten, for example, is sintered for a relatively long time. Standard industrial powder sintering

More