A method for preparing high-strength supported semi-vitrified ceramsite by using low-siliceous red mud raw material

Abstract

The invention discloses a method for preparing high-strength supported semi-vitrified ceramsite by using low-siliceous red mud raw materials. The method is to carry out dealkalization, drying and grinding pretreatment on the red mud to obtain red mud powder; After mixing evenly with the plasticizer, press molding to obtain a cylindrical ceramsite green body; the green body is dried and sintered to obtain ceramsite with a compressive strength ≥ 80MPa. Forming and sintering parameter control means to form a multi-component eutectic semi-vitrified ceramic support, replacing the mullite crystal phase support in traditional ceramsite, breaking through the ceramsite's high SiO 2 The limitation of composition requirements overcomes the restrictions on the production of ceramsite due to the large fluctuation of red mud composition and high alkalinity. While ensuring the strength of supporting ceramsite, it greatly increases the amount of red mud added, which is conducive to the production of red mud. Reduce and recycle, and solve the problem of red mud stockpiling.

Description

technical field

[0001] The invention relates to a method for preparing ceramsite, in particular to a method for directly preparing high-strength supported semi-vitrified ceramsite by using red mud, a low-silicon raw material, and belongs to the technical field of comprehensive utilization of metallurgical solid waste. Background technique

[0002] Red mud is an alkaline solid waste produced during the alumina production process. As of 2018, the global red mud stockpile is estimated to have reached 3.6 billion tons, and is growing at a rate of about 120 million tons per year. The average utilization rate of red mud in the world is 15%, and China, as a major producer of alumina and red mud, has a red mud utilization rate of only 4%. A lot of research has been done on the treatment of red mud at home and abroad. Most of the methods are difficult to realize industrialization due to the limitation of red mud treatment volume, process economy, product potential risk and practical...

Examples

Embodiment 1

[0031] Red mud from an alumina plant in Guangxi was used to dealkalize (to Na 2 O content 2.8%), after drying, the main components and content are SiO 2 11%, Fe 2 o 3 29%, Al 2 o 3 15%, CaO 14%, H 2 O 15%. Grind the dried red mud to below 100 mesh, add 5% deionized water and mix well. Take the above-mentioned red mud material and put it into a pressure mold, shape it on the press with a pressure of 20MPa to make a cylindrical ceramsite green body with a diameter of 0.6cm and a height-to-diameter ratio of 0.8, dry it again and place it in a high-temperature furnace for sintering at 1150°C 1h, and then air-cooled to room temperature to obtain a high-strength red mud-based ceramsite product with a peak compressive strength of 335MPa. It can be seen from the XRD pattern of ceramsite products that a semi-vitrified ceramic body with high iron and low silicon multi-component eutectic is formed.

Embodiment 2

[0033] Red mud from an alumina plant in Guangxi was used to dealkalize (to Na 2 O content 2.8%), after drying, the main components and content are SiO 2 11%, Fe 2 o 3 29%, Al 2 o 3 15%, CaO 14%, H 2 O 15%. Grind the dried red mud to below 100 mesh, add 5% deionized water and mix well. Take the above-mentioned red mud material and put it into a pressure mold, shape it on the press with a pressure of 20MPa to make a cylindrical ceramsite green body with a diameter of 0.6cm and a height-to-diameter ratio of 0.8, dry it again and place it in a high-temperature furnace for sintering at 950°C 2h, and then air-cooled to room temperature to obtain a high-strength red mud-based ceramsite product with a peak compressive strength of 180MPa.

Embodiment 3

[0035] Red mud from an alumina plant in Shandong was used for dealkalization (to Na 2 O content 2.6%), after drying, the main component and content are SiO 2 17%, Fe 2 o 3 32%, Al 2 o 3 18%, CaO 10%, H 2 O 11%. Grind the dried red mud to below 100 mesh, add 10% bio-organic waste liquid and mix evenly. Take the above-mentioned red mud material and put it into a pressure mold, shape it on the press with a pressure of 10MPa to make a cylindrical ceramsite green body with a diameter of 0.6cm and a height-to-diameter ratio of 0.8, dry it again and place it in a high-temperature furnace for sintering at 1250°C 1h, and then air-cooled to room temperature to obtain a high-strength red mud-based ceramsite product with a peak compressive strength of 82MPa.

technical field

[0001] The invention relates to a method for preparing ceramsite, in particular to a method for directly preparing high-strength supported semi-vitrified ceramsite by using red mud, a low-silicon raw material, and belongs to the technical field of comprehensive utilization of metallurgical solid waste. Background technique

[0002] Red mud is an alkaline solid waste produced during the alumina production process. As of 2018, the global red mud stockpile is estimated to have reached 3.6 billion tons, and is growing at a rate of about 120 million tons per year. The average utilization rate of red mud in the world is 15%, and China, as a major producer of alumina and red mud, has a red mud utilization rate of only 4%. A lot of research has been done on the treatment of red mud at home and abroad. Most of the methods are difficult to realize industrialization due to the limitation of red mud treatment volume, process economy, product potential risk and practical...

Examples

Embodiment 1

[0031] Red mud from an alumina plant in Guangxi was used to dealkalize (to Na 2 O content 2.8%), after drying, the main components and content are SiO 2 11%, Fe 2 o 3 29%, Al 2 o 3 15%, CaO 14%, H 2 O 15%. Grind the dried red mud to below 100 mesh, add 5% deionized water and mix well. Take the above-mentioned red mud material and put it into a pressure mold, shape it on the press with a pressure of 20MPa to make a cylindrical ceramsite green body with a diameter of 0.6cm and a height-to-diameter ratio of 0.8, dry it again and place it in a high-temperature furnace for sintering at 1150°C 1h, and then air-cooled to room temperature to obtain a high-strength red mud-based ceramsite product with a peak compressive strength of 335MPa. It can be seen from the XRD pattern of ceramsite products that a semi-vitrified ceramic body with high iron and low silicon multi-component eutectic is formed.

Embodiment 2

[0033] Red mud from an alumina plant in Guangxi was used to dealkalize (to Na 2 O content 2.8%), after drying, the main components and content are SiO 2 11%, Fe 2 o 3 29%, Al 2 o 3 15%, CaO 14%, H 2 O 15%. Grind the dried red mud to below 100 mesh, add 5% deionized water and mix well. Take the above-mentioned red mud material and put it into a pressure mold, shape it on the press with a pressure of 20MPa to make a cylindrical ceramsite green body with a diameter of 0.6cm and a height-to-diameter ratio of 0.8, dry it again and place it in a high-temperature furnace for sintering at 950°C 2h, and then air-cooled to room temperature to obtain a high-strength red mud-based ceramsite product with a peak compressive strength of 180MPa.

Embodiment 3

[0035] Red mud from an alumina plant in Shandong was used for dealkalization (to Na 2 O content 2.6%), after drying, the main component and content are SiO 2 17%, Fe 2 o 3 32%, Al 2 o 3 18%, CaO 10%, H 2 O 11%. Grind the dried red mud to below 100 mesh, add 10% bio-organic waste liquid and mix evenly. Take the above-mentioned red mud material and put it into a pressure mold, shape it on the press with a pressure of 10MPa to make a cylindrical ceramsite green body with a diameter of 0.6cm and a height-to-diameter ratio of 0.8, dry it again and place it in a high-temperature furnace for sintering at 1250°C 1h, and then air-cooled to room temperature to obtain a high-strength red mud-based ceramsite product with a peak compressive strength of 82MPa.

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