Segment treatment method for fluorine-containing heavy metal wastewater

Abstract

The invention provides a segment treatment method for fluorine-containing heavy metal wastewater. The method comprises the specific steps: after chemical reduction treatment of wastewater, adding a pre-neutralizing agent into a front segment settling tank to allow complexing precipitation of metal ions in the wastewater to occur, and carrying out concentration and plate-frame pressure filtration on sludge to obtain front segment sludge; feeding a supernate into a rear segment settling tank, then adding a post-neutralizing agent, discharging the supernate which meets the standard, allowing complexing precipitation of Ca<2+>, F<->, SO4<2-> and the like in the wastewater to occur, carrying out concentration and plate-frame pressure filtration on sludge to obtain rear segment sludge, and drying and smashing the sludge to obtain a cement mineralizer; and uniformly mixing the cement mineralizer with limestones, clay, a correcting material and the like, and grinding and calcining the mixture according to a conventional cement production and processing process to obtain cement clinker. The method provided by the invention not only realizes resource utilization of stainless steel cold-rolled sludge which can effectively replace natural gypsum and fluorite, thereby better satisfying the demand of low-temperature sintering, high quality and high yield, energy saving and consumption reduction of the cement clinker.

Description

technical field [0001] The invention belongs to the technical field of segmental treatment and comprehensive utilization of stainless steel cold-rolling pickling wastewater, and specifically relates to a method for preparing a cement mineralizer and using method thereof as a raw material for treating the rear-stage sludge produced by stainless steel cold-rolling pickling wastewater. Background technique [0002] During the surface treatment of stainless steel cold-rolled coils, a large amount of pickling wastewater will be discharged, of which T.Fe, Cr 6+ , T.Cr, Ni 2+ , Zn 2+ , Pb 2+ , F - , SS and other pollutants have high content and great harm, and they must be treated to meet the standards before they are allowed to be discharged. [0003] Due to the consideration of mature technology, operating cost and convenient maintenance, etc., the current treatment process for stainless steel cold rolling pickling wastewater is mainly chemical reduction-precipitation method,...

AI Technical Summary

Problems solved by technology

The disadvantage of this process is that in order to ensure that the effluent reaches the standard, it is often necessary to add excessive lime milk, which will lead to a large output of cold rolling sludge and complex components (based on metal hydroxide, water-soluble salt, calcium fluoride, calcium sulfate, Calcium oxide is the main component, and the typical components are shown in Table 1), the treatment and disposal are difficult, the comprehensive cost of its treatment is quite high, and the above-mentioned treatment process is prone to secondary pollution, so this kind of mixed sludge is identified as Hazardous waste (No. HW17 in China National Hazardous Waste Catalog)

In production practice, high-grade fluorite and gypsum mining, transportation and processing costs are high, leading to an increase in cement manufacturing costs (according to research, the cost of cement mineralizer per ton is about 15-50 yuan)

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