A method for preparing recycled aggregate from Bayer process red mud

A Bayer process red mud and recycled aggregate technology, which is applied in the direction of sustainable waste treatment, solid waste management, climate sustainability, etc., can solve the problem that industrial application cannot be truly realized, red mud dealkalization pretreatment costs are high, and there is no solution High alkalinity of red mud and other problems, achieve good solidification and stability, reduce energy consumption, and protect mineral resources

Active Publication Date: 2022-03-22
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1. The utilization rate of red mud is low, which can only be placed in the laboratory stage and cannot be truly industrialized
[0005] 2. The problem of high alkalinity and heavy metals in red mud is not solved, and the harm to the environment is not solved, and there is a lack of mechanical technical means
[0006] 3. The preparation process is complicated, and the cost of red mud dealkalization pretreatment is too high

Method used

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  • A method for preparing recycled aggregate from Bayer process red mud
  • A method for preparing recycled aggregate from Bayer process red mud
  • A method for preparing recycled aggregate from Bayer process red mud

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preparation example Construction

[0048] In the preparation process of solid waste-based sulfoaluminate cement and red mud-based aggregate, the same batch of red mud, desulfurized gypsum, and carbide slag are used as raw materials.

[0049] The preparation process of solid waste-based sulphoaluminate cement:

[0050] Table 1. The chemical composition of raw materials for the preparation of solid waste-based sulphoaluminate cement

[0051]

[0052]

[0053] Solid waste-based sulphoaluminate cement uses red mud, desulfurized gypsum, aluminum ash, and calcium carbide slag. According to the raw material ratio shown in Table 2, it is ground-mixed-calcined in a rotary kiln at 1250°C and held for 45 minutes. -Solid waste-based sulphoaluminate cement clinker-Solid waste-based sulphoaluminate cement, to realize the preparation of solid waste-based sulphoaluminate cement.

[0054] Table 2. Raw material ratio for preparing solid waste-based sulphoaluminate cement

[0055] red mud Desulfurization gypsu...

Embodiment 1

[0057] The raw materials were weighed according to the following percentages by weight: 30% solid waste-based sulphoaluminate cement, 60% Bayer process red mud, 5% desulfurized gypsum, and 5% carbide slag.

[0058] Dry the Bayer red mud at 105°C, add solid waste-based sulphoaluminate cement according to the above ratio and grind it evenly in a ball mill, control the fineness by controlling the grinding time, and break the red mud by means of mechanical grinding Middle Al 2 o 3 and SiO 2 The Al-O chemical bond and Si-O chemical bond in the mixture can stimulate the potential activity and improve the performance of the red mud-based aggregate. The particle size range of the prepared active mixed powder is more than 200 mesh (0.075mm).

[0059] Then mix and grind the above mixed powder with 5% desulfurized gypsum and 5% carbide slag for 5 minutes, and add water equivalent to 8% of the total mass of solid waste raw materials. Two kinds of molds with a diameter of r = 15mm and a...

Embodiment 2

[0061] The raw materials were weighed according to the following percentages by weight: 25% solid waste-based sulphoaluminate cement, 65% Bayer process red mud, 5% desulfurized gypsum, and 5% carbide slag.

[0062] Dry the Bayer red mud at 105°C, add solid waste-based sulphoaluminate cement according to the above ratio and grind it evenly in a ball mill, control the fineness by controlling the grinding time, and break the red mud by means of mechanical grinding Middle Al 2 o 3 and SiO 2 The Al-O chemical bond and Si-O chemical bond in the mixture can stimulate the potential activity and improve the performance of the red mud-based aggregate. The particle size range of the prepared active mixed powder is above 200 mesh (0.075mm).

[0063] Then mix and grind the above mixed powder with 5% desulfurized gypsum and 5% carbide slag for 5 minutes, and add water equivalent to 8% of the total mass of solid waste raw materials. Two kinds of molds with a diameter of r = 15mm and a cyl...

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Abstract

The invention belongs to the field of solid waste treatment, and relates to a method for preparing recycled aggregate by using Bayer process red mud, comprising: drying the Bayer process red mud, mixing with cement, and ball milling to obtain an active mixture; Mix with desulfurized gypsum and calcium carbide slag, grind, add water, and dry-press to obtain red mud-based recycled aggregate; dry-press molding, the process is simple, and there is no need for high-temperature sintering and dealkalization pretreatment of red mud, reducing Energy consumption reduces preparation cost. It can realize the complementary effect of Bayer process red mud and solid waste-based sulphoaluminate cement. The high alkalinity of red mud promotes the hydration of solid waste-based sulphoaluminate cement, and the calcium produced by the hydration of solid waste-based sulphoaluminate cement Alumite has a good solidification and stabilization effect on heavy metal Cr in red mud. All solid waste preparation, low preparation cost, energy saving and emission reduction, lower energy consumption, good performance, can be used to replace stones as aggregates, reduce mining, and protect my country's mineral resources.

Description

technical field [0001] The invention belongs to the field of solid waste treatment, and in particular relates to a method for preparing recycled aggregates from Bayer process red mud. Background technique [0002] The information disclosed in this background section is only intended to increase the understanding of the general background of the present invention, and is not necessarily taken as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. [0003] At present, red mud recycled aggregates are often mixed with red mud and various solid waste materials to prepare recycled aggregates. But the disadvantages are: [0004] 1. The utilization rate of red mud is low, which can only be placed in the laboratory stage and cannot be truly industrialized. [0005] 2. The harm to the environment caused by the high alkalinity and heavy metal content of red mud is not solved, and there is a lack of mech...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B18/02C04B18/04
CPCC04B18/021C04B18/0409C04B22/145C04B22/064Y02W30/91
Inventor 王文龙王冠张超王旭江李敬伟吴长亮蒋稳
Owner SHANDONG UNIV
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