Method for preparing recycled aggregate from Bayer process red mud

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, which comprises the following steps: drying Bayer process red mud, mixing with cement, and carrying out ball milling to obtain an active mixture; and mixing the active mixture with desulfurized gypsum and carbide slag, grinding, adding water, and carrying out dry pressing molding to obtain red mud-based recycled aggregate. The preparation method has the advantages of dry pressing molding, simple process, no need of high-temperature sintering process, no need of dealkalization pretreatment of red mud, energy consumption reduction and preparation cost reduction. The synergistic complementary effect of the Bayer process red mud and the solid-waste-based sulphoaluminate cement can be achieved, the high alkalinity of the red mud promotes the solid-waste-based sulphoaluminate cement to be hydrated, and ettringite generated by hydrating the solid-waste-based sulphoaluminate cement has a good curing and stabilizing effect on heavy metal Cr in the red mud. The material is prepared from all solid wastes, has the advantages of low preparation cost, energy conservation, emission reduction, energy consumption reduction and good performance, can be used as an aggregate instead of pebbles, reduces mining and protects mineral resources in China.

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...

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

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