Comprehensive utilization method of fluosilicic acid-containing wastewater

Abstract

The invention relates to a comprehensive utilization method of fluosilicic acid-containing wastewater, which comprises the following steps: carrying out decomposition reaction on a calcium-containing raw material and a dissolution medium, carrying out carbonization conversion reaction on a calcium-containing solution obtained by the decomposition reaction and carbon dioxide, mixing a calcium carbonate solid obtained by the carbonization conversion reaction with silicon-removal fluorine-containing wastewater and an additive, and reacting to obtain calcium fluoride solids, wherein the fluosilicic acid-containing wastewater is mixed with a silicon-removal reaction medium, a silicon-removal reaction is carried out, and silicon-removal fluorine-containing wastewater and white carbon black are obtained through liquid-solid separation. According to the comprehensive utilization method, the calcium fluoride solid with controllable morphology, controllable granularity and controllable purity can be prepared, the purity of the calcium fluoride solid can be higher than 99.9%, white carbon black byproducts can be obtained, the comprehensive recovery rate of fluorine resources is increased to 90% or above, the technological conditions are mild, no special requirements for equipment materials and types exist, industrial operability is high, and the application range is wide.

Description

technical field [0001] The invention relates to the field of fluorine-containing wastewater treatment, in particular to a comprehensive utilization method of fluorine-containing silicic acid wastewater. Background technique [0002] Fluorspar, also known as fluorspar, is mainly composed of calcium fluoride (CaF 2 ), is my country's strategic mineral resources, has the scarcity and strategic significance of "rare earth", and its application fields cover chemical industry, metallurgy, cement, glass, ceramics, optics, electronics, new energy, national defense, medicine and other traditional and emerging industries . Because of its irreplaceable use, it is known as the "second rare earth". [0003] According to the "Mineral Commodity Summaries 2019" released by the US Geological Survey, the world's fluorite resource reserves are 310 million tons, and my country's fluorite resource reserves are 42 million tons, accounting for 13.5% of the world. However, my country's annual flu...

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Problems solved by technology

Although the process described above can reduce the concentration of fluoride ions in the water to the greatest extent and ensure that the effluent is discharged up to the standard, the generated fluorine-containing sludge still cannot separate high-quality calcium fluoride solids, and there is still the problem of secondary pollution, and the cost of raw materials is high. higher

[0011] In summary, although the prior art discloses some treatment methods for fluorine-containing wastewater, there are few studies on the treatment methods for fluorine-containing silicic acid wastewater. The comprehensive utilization of fluosilicic acid wastewater to prepare calcium fluoride solids and silica by-products with controllable shape, particle size, and purity is rarely reported.

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