Novel wastewater fluorine-removing technology

Abstract

The invention relates to a novel wastewater fluorine-removing technology. The original technology and equipment can be maximally utilized, waste acid is subjected to a vulcanization treatment so as to remove most heavy metal pollutants, then the waste acid is pre-neutralized in the gypsum step, and the fluorine content of gypsum filtrate in the outlet can be controlled under 60-100 mg / L. Then calcium carbide slag is used to neutralize gypsum filtrate, a flocculating agent is added to carry out flocculation, finally the filtrate is filtered to remove the heavy metal pollutants in wastewater, and the fluorine concentration of the flocculation filtrate can be controlled under 20 to 40 mg / L. Then an aluminum sulfate solution is added to absorb and complex the fluorine ions, the fluorine concentration of wastewater can be reduced to 5 mg / L or less, and other element concentrations are qualified.

Description

technical field [0001] The invention relates to a process for treating high-concentration fluorine-containing wastewater in the metallurgical industry, which is a process for removing fluoride from wastewater by combining a step-by-step precipitation method and an adsorption method, and belongs to the technical field of industrial wastewater treatment. Background technique [0002] Industries such as smelting are affected by the fluorine content in raw materials, and the acidic wastewater generated during the production process often contains relatively high concentrations of fluoride. For these wastewaters, most domestic enterprises do not have perfect defluorination facilities at present. Wastewater is generally pretreated by sulfuration method first, by adding Na 2 S solution removes most of the heavy metal pollutants, fluorine cannot be removed in this link, and then by adding lime milk CaCO 3 The solution is pre-neutralized, and the pH is controlled to be about 3~5, a...

AI Technical Summary

Problems solved by technology

The disadvantages are: the amount of wastewater in industrial production is large, and the concentration of fluorine in the wastewater is high. Although the above process can remove most of the fluorine in the wastewater, the fluorine concentration is still higher than 5mg / L, which cannot meet the national discharge standards; The process of defluoridation mainly adopts aluminum salt to remove fluoride. The disadvantage is that this process is only suitable for wastewater with low fluorine concentration. It is impossible for salt to remove fluorine and cadmium at the same time under any pH conditions, so it may lead to excess cadmium in wastewater