WO2011075286A1 - Process for making boehmite

This invention comprises a novel process for making boehmite alumina and comprises selecting an alumina, and heating it in the presence of an alkali metal hydroxide concentration of at least 0.2...

Process for the production of boehmitic aluminas -

A process for the preparation of a boehmitic alumina compound comprising the steps of: hydrolysizing a mixture consisting essentially of neutral aluminum alkoxide and

Boehmite Process – A New Approach in Alumina

process is that Boehmite is efficiently produced by precip- itation from Bayer liquors under atmospheric conditions. The new process can be used for the production of smelter

Method for making modified boehmite alumina -

1999-8-21  A process for making a modified boehmite alumina comprising reacting at elevated temperatures a boehmite alumina with a compound having the formula: X(SO 3 M) n wherein X is an Method for making modified boehmite alumina - Condea Vista Company

US4117105A - Process for preparing dispersible

4. A process for preparing dispersible colloidal sized particles of boehmite alumina, comprising the steps of: (a) calcining the gibbsite form of alumina trihydrate at a temperature between 200°...

Process For Making Boehmite Alumina -

duel drive motor in a ball mill in malaysia. 2021-6-27 duel drive motor in a ball mill in malaysia. Ball mills are commonly used in the manufacture of Portland cement and finer grinding stages of mineral processing one example being the Sepro tyre drive Grinding Mill Industrial ball mills can be as large as 85 m 28 ft in diameter with a 22 MW motor drawing approximately 00011 of the total ...

Preparation of alumina having increased porosity -

1995-2-22  Basically, the process disclosed in U.S. Pat. No. 4,676,928 involves taking a precursor boehmite alumina, forming the precursor alumina into an aqueous slurry or mixture, the pH being in the range of from about 5 to about 9, and then heating the aqueous slurry of the precursor alumina at elevated temperatures, generally about 70° C. or greater, for a sufficient period of time to convert the greater portion of the precursor boehmite alumina

Boehmite modification of nano grade α-alumina and

2007-7-1  The pre-aging process was performed by adding boehmite to a nano grade α-alumina (Nα-A) slurry and adjusting the pH value of the mixed slurry to less than 4. After the pre-aging process, boehmite was coated onto the surface of Nα-A particles to change its zero charged point (PZC) from pH = 6–7 to 9–10, similar to that of the boehmite slurry.

Effect of temperature and alumina/caustic ratio on ...

2007-8-1  This process if developed would reduce the energy consumption for making alumina. The present work is aimed to carry out boehmite precipitation under atmospheric pressure conditions. Parameters such as alumina/caustic (A/C) ratio and temperature are varied to precipitate out boehmite from synthetically prepared sodium aluminate liquor.

Process for the production of boehmitic aluminas -

The present invention relates to a process for the production of boehmitic aluminas. More particularly, the invention relates to the production of boehmitic alumina compounds having a purity of at least 99.95% Al 2 O 3 with specific, adjustable pore radii of between 3 and 100 nm.. In the neutral hydrolysis of aluminum alkoxides, e.g., as described in DE-AS 1 258 854, aluminas with a boehmite ...

Process for Producing High Porosity Boehmite

The process of the present invention employs an aqueous slurry of a boehmite alumina containing from about 9 to about 12 wt. % alumina, calculated as Al 2 O 3. In general, the process is conducted at a temperature of from 100-160EC, preferably from 130-160EC.

Production of micro-crystalline boehmite from

2013-2-1  A hydrothermal leaching process was developed to produce fire retarding micro-boehmite (4–25 mm) using plant aluminium hydroxide (alumina trihydate, ATH) ( 200 °C, 1–2 MPa after 1 hour. ...

Process of preparing high purity alumina bodies -

The starting alumina material consists of 1000 pounds of boehmite alumina based on the weight of anhydrous Al 2 O 3 which is prepared by the process of U.S. Pat. No. 4,202,870. 200 pounds of this boehmite alumina and 700 pounds of water are mixed in a stainless steel tank by stirring. To this aqueous alumina slurry is supplied a solution ...

Boehmite modification of nano grade α-alumina and

2007-7-1  The pre-aging process was performed by adding boehmite to a nano grade α-alumina (Nα-A) slurry and adjusting the pH value of the mixed slurry to less than 4. After the pre-aging process, boehmite was coated onto the surface of Nα-A particles to change its zero charged point (PZC) from pH = 6–7 to 9–10, similar to that of the boehmite slurry.

Effect of temperature and alumina/caustic ratio on ...

2007-8-1  This process if developed would reduce the energy consumption for making alumina. The present work is aimed to carry out boehmite precipitation under atmospheric pressure conditions. Parameters such as alumina/caustic (A/C) ratio and temperature are varied to precipitate out boehmite from synthetically prepared sodium aluminate liquor.

Bayer Process: Manufacturing Of Alumina Making of

Bayer process of producing alumina can be divided into following four steps: i. Digestion: In this step of Bayer process, bauxite ore is crushed, milled and then heated with sodium hydroxide at the temperature of around 150-200 degree Celsius. In the Bauxites, aluminium compounds are present as gibbsite (Al (OH) 3), boehmite (AlOOH) and ...

Innovative Process for Boehmite Precipitation in Bayer ...

2019-8-21  Boehmite contains 1 mole of water against three for gibbsite, resulting in energy savings of about 50% in calcination. Also, the amount of the material required to be calcined will be reduced by about 360 kg/t of alumina produced and will save additional energy of about 0.7 GJ/t Al 2 O 3 and achieve an increase in the calciner productivity [].The studies conducted here were carried out to ...

Preparation and Properties of Pseudo-boehmite

2018-12-17  A sintering–CO2 decomposition process for preparation of pseudo-boehmite is proposed for clean valorization of high-alumina fly ash. The effects of different synthesis conditions on the crystal structure and textual properties of the pseudo-boehmite were studied systematically. The results showed that the main product was NaAlCO3(OH)2 when the decomposition terminal pH was below 9.5, and

Hydrothermal synthesis of boehmite and α-alumina

2006-11-14  α-Alumina (Al 2 O 3) is a ceramic material used widely due to its versatile properties such as high temperature stability, high strength at high temperature, high hardness with higher wear resistance, good thermal shock resistance etc [1, 2].In addition, it is available abundantly at relatively low cost, therefore, is a popular material for fabrication of structural components, electronic ...

Preparation of alumina through a sol–gel process ...

Hydrated boehmite with nano-sized crystallites AlO(OH)0.8H 2 O are obtained through a very reproducible sol–gel procedure and characterized using powder X-ray diffraction, in-situ IR spectroscopy, thermal analysis, BET surface area and photoelectron spectroscopy.. The thermal evolution of hydrated boehmite leads first to hydrated γ-alumina Al 2 O 3 0.33H 2 O = Al 2 O 2.67 (OH) 0.66 and ...

Effect of temperature and alumina/caustic ratio on ...

This process if developed would reduce the energy consumption for making alumina. The present work is aimed to carry out boehmite precipitation under atmospheric pressure conditions. Parameters such as alumina/caustic (A/C) ratio and temperature are varied to precipitate out boehmite from synthetically prepared sodium aluminate liquor.

Preparation and Properties of Pseudo-boehmite

2018-12-17  A sintering–CO2 decomposition process for preparation of pseudo-boehmite is proposed for clean valorization of high-alumina fly ash. The effects of different synthesis conditions on the crystal structure and textual properties of the pseudo-boehmite were studied systematically. The results showed that the main product was NaAlCO3(OH)2 when the decomposition terminal pH was below 9.5, and

Bayer Process: Manufacturing Of Alumina Making of

Bayer process of producing alumina can be divided into following four steps: i. Digestion: In this step of Bayer process, bauxite ore is crushed, milled and then heated with sodium hydroxide at the temperature of around 150-200 degree Celsius. In the Bauxites, aluminium compounds are present as gibbsite (Al (OH) 3), boehmite (AlOOH) and ...

Innovative Process for Boehmite Precipitation in Bayer ...

2019-8-21  Boehmite contains 1 mole of water against three for gibbsite, resulting in energy savings of about 50% in calcination. Also, the amount of the material required to be calcined will be reduced by about 360 kg/t of alumina produced and will save additional energy of about 0.7 GJ/t Al 2 O 3 and achieve an increase in the calciner productivity [].The studies conducted here were carried out to ...

Nanocrystalline Functional Alumina and Boehmite

2019-5-29  antireflective applications to the as-prepared nanocrystalline alumina and boehmite materials. Based on a modified sol-gel process, nanocrystalline flaky boehmite powder was synthesized, and transition alumina powders with morphologies of nanoparticles and nanorods with high surface areas were prepared from the flaky boehmite powder.

Improved process for the extraction of alumina from ...

CLAIMS: 1. A process for the extraction of alumina from bauxite having a relatively high boehmite content including the steps of digestion of the gibbsite fraction of the bauxite, solid/liquid separation and digestion of the boehmite fraction, said process being characterised by relatively fast low temperature digestion of gibbsite fraction to give a high A/C ratio liquor, negligible boehmite ...

Process for obtaining material through modification of ...

NOVELTY – Process for obtaining a biocompatible material (I) through the modification of a material formed by alumina, sapphire, boehmite, aluminum oxide hydroxides and/or metallic aluminum, comprises reacting the material with dicarboxylic acid dissolved in

Hydrothermal synthesis of boehmite and α-alumina

2006-11-14  α-Alumina (Al 2 O 3) is a ceramic material used widely due to its versatile properties such as high temperature stability, high strength at high temperature, high hardness with higher wear resistance, good thermal shock resistance etc [1, 2].In addition, it is available abundantly at relatively low cost, therefore, is a popular material for fabrication of structural components, electronic ...

Theoretical Study of the Dehydration Process of

2021-3-12  The topotactic transformation of boehmite (AlOOH) taking place under calcination and leading to γ-alumina (γ-Al2O3) has been investigated theoretically and a step-by-step mechanism for the structural transformation is proposed. This mechanism reveals two major steps. First, the structural collapse of boehmite occurs, after hydrogen transfers and water extraction. Then, through an



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