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Non-bayer-process red mud staged deep dealkalization method

A Bayer red mud and deep dealkalization technology, which is applied in the field of red mud deep dealkalization in stages, to achieve mineralization fixation, avoid alkaline rebound, and improve the impact of the surrounding environment

Active Publication Date: 2015-12-09
CHONGQING INST OF GREEN & INTELLIGENT TECH CHINESE ACADEMY OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

CN104445844A introduces a method of dealkalizing red mud with flue gas combined with alkaline materials, the essence of which is to first introduce cations to combine with basic anions in red mud to form insoluble solids, and then introduce flue gas to neutralize excess Cations, however, are powerless against the potential calcium, magnesium and other alkaline substances that exist in large quantities in red mud in our country
CN101423318B first uses dilute sulfuric acid to pretreat red mud, and then uses calcium oxide to further dealkalize under pressure. This method also does not further treat alkaline substances such as calcium and magnesium in red mud

Method used

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  • Non-bayer-process red mud staged deep dealkalization method

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Experimental program
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Effect test

Embodiment 1

[0031] like figure 1 As shown, the step-by-step deep dealkalization of non-Bayer process red mud is carried out as follows:

[0032] (1) Red mud solid and water are prepared into a suspension at a solid-to-liquid ratio of 1:5, and then introduced into a reaction device with stirring, the stirring speed is controlled at 800 rpm, and carbon dioxide is introduced to reach saturation. During the reaction, the control The temperature of the reaction system was 25° C., the pressure was maintained at normal pressure, and the reaction time was 200 minutes. After the reaction is finished, the suspension is subjected to solid-liquid separation by centrifugation, and the obtained liquid is poured into the carbonation mother liquor in the alumina production process for unified treatment, and then reused in the dissolution process, and the obtained solid enters the next step for deep dealkalization.

[0033] (2) Acetic acid and water are prepared into an extract with a molar concentration...

Embodiment 2

[0036] (1) Red mud solids and water are prepared into a suspension at a solid-to-liquid ratio of 1:1, and then introduced into a reaction device with stirring, the stirring speed is controlled at 800 rpm, and then carbon dioxide is introduced to reach saturation for reaction. During the reaction The temperature of the reaction system was controlled at 50° C., the pressure was maintained at 10 bar, and the reaction time was 600 minutes. After the reaction is finished, the suspension is subjected to solid-liquid separation by centrifugation, and the obtained liquid is poured into the carbonation mother liquor in the alumina production process for unified treatment, and then reused in the dissolution process, and the obtained solid enters the next step for deep dealkalization.

[0037] (2) Prepare citric acid and water into an extract with a molar concentration of 0.05 mol / liter, then uniformly mix the red mud solid after centrifugation in step (1) with the extract at a mass ratio...

Embodiment 3

[0040] (1) Prepare red mud solid and water into a suspension at a solid-to-liquid ratio of 1:15, then introduce it into a reaction device with stirring, control the stirring speed at 800 rpm, and then feed carbon dioxide to reach saturation for reaction. During the reaction The temperature of the reaction system was controlled at 45° C., the pressure was maintained at 8 bar, and the reaction time was 30 minutes. After the reaction is finished, the suspension is subjected to solid-liquid separation by centrifugation, and the obtained liquid is poured into the carbonation mother liquor in the alumina production process for unified treatment, and then reused in the dissolution process, and the obtained solid enters the next step for deep dealkalization.

[0041] (2) Succinic acid and water are prepared into an extract with a molar concentration of 0.1 mol / liter, and then the red mud solid after centrifugation in step (1) is uniformly mixed with the extract at a mass ratio of 1:1 t...

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Abstract

The invention relates to a non-bayer-process red mud staged deep dealkalization method, and belongs to the technical field of resource integral utilization. The method mainly comprises the following steps that (1) red mud solid and water are prepared into suspension liquid according to a solid-liquid ratio being 1:1 to 1:15; the materials are stirred; CO2 is introduced to reach the saturation state, the temperature is room temperature to 50 DEG C, the pressure is normal pressure to 10bars, and the time is 30 to 1000 minutes; centrifugalization is performed; (2) red mud solids subjected to separation are uniformly mixed with extraction liquid containing unitary or / and polynary carboxylic acid as extraction agents according to the mass ratio being 1:1 to 1:10 to be prepared into suspension liquid; the suspension liquid is charged into a high-pressure reaction container; the materials are stirred; meanwhile, CO2 is introduced for deep dealkalization. The method has the advantages that the red mud is subjected to deep dealkalization in different stages, so that the strong alkalinity and the continuous alkalinity release characteristics of the red mud are weakened; the stable state using the insoluble carbonates as a main form is reached; the influence on the peripheral environment is greatly reduced.

Description

technical field [0001] The invention relates to a method for deep dealkalization of red mud in stages, in particular to a method for combining deep dealkalization of red mud with non-Bayer method and mineralization and fixation of carbon dioxide, and belongs to the technical field of comprehensive utilization of resources. Background technique [0002] Red mud is an alkaline solid waste produced during the alkaline production of alumina from bauxite. Depending on the ore raw materials and production processes, the output of red mud per ton of alumina produced ranges from a few hundred kilograms to several tons. Red mud is a typical bulk solid waste, and its comprehensive treatment is still a worldwide problem. [0003] Attempts have been made in the world to store and cover soil and modify it to treat red mud in the way of plant greening, so that it can gradually return to nature, but due to the inherent characteristics of red mud such as strong alkalinity, alkaline continu...

Claims

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Application Information

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IPC IPC(8): C02F11/00
Inventor 陈鸿珍王光伟徐愿坚
Owner CHONGQING INST OF GREEN & INTELLIGENT TECH CHINESE ACADEMY OF SCI