Preparation method of red mud-slag-cement composite dephosphorization agent

Abstract

The invention provides a preparation method of a red mud-slag-cement composite dephosphorization agent, comprising the steps of drying the materials of red mud, slag and cement, crushing, screening, drying to constant weights, and mixing well in a certain ratio; mixing the mixture with deionized water to obtain raw particles; subjecting the raw particles to microwave activation, and cooling to room temperature to obtain the red mud-slag-cement composite dephosphorization agent. All the red mud, slag and cement have high calcium oxide content; phosphates in water are removed in calcium phosphate form via calcium-based components; iron oxide in the red mud and slag are heated quickly under the action of microwave, so that calcining is achieved; hydrated minerals, carbonate minerals and the like in the red mud and slag decompose easily and easily release water or gas, and pore structures are formed in the particles; the slag has incompletely combusted ash in a certain ratio, and pore forming can also be achieved in the microwave activation process.

Description

technical field [0001] The invention relates to a method for preparing a phosphorus removal agent by using red mud, slag and cement as raw materials through microwave activation, and belongs to the field of comprehensive utilization of red mud. Background technique [0002] Excessive nutrients such as nitrogen and phosphorus in the water will cause eutrophication of the water body, resulting in the rapid reproduction of algae and other plankton, a decrease in the dissolved amount of the water body, deterioration of water quality, and massive death of fish and other organisms. Eutrophication of water body seriously affects water quality and destroys ecological environment. Therefore, in order to prevent the occurrence of eutrophication in water bodies, in addition to controlling the discharge of phosphorus at the source, it is very important to find an economical and environmentally friendly phosphorus removal agent. [0003] Red mud has the characteristics of fine particles...

AI Technical Summary

Problems solved by technology

The red mud powder material modified by chemical means has good phosphorus removal performance, but the preparation cost and conditions are relatively high, and it is difficult to recycle and regenerate the material after use; and chemical means are often used for acid pretreatment, which is harmful to the environment. certain pollution

The thermal activation method can form a pore structure inside the red mud particles and increase the specific surface area, but the temperature required for roasting is high, the heating process consumes energy, and the heat is transferred from the surface of the material to the inside in the form of conduction, convection or radiation. In this way, there may be a thermal gradient difference between the surface layer and the interior of the material, resulting in uneven activation degrees inside and outside the material, and if the heating rate is controlled and the activation time is prolonged, this method will undoubtedly consume more energy.