Method for preparing casting covering slag by utilizing stainless steel cold-rolling pickling wastewater

Abstract

The invention discloses a method for preparing casting covering slag by utilizing stainless steel cold-rolling pickling wastewater, which comprises the following steps of: after the stainless steel cold-rolling pickling wastewater is chemically reduced, adding a first neutralizing agent into a front-section precipitation tank to complex and precipitate heavy metal ions in the wastewater, concentrating, dehydrating and drying precipitates and returning the precipitates to a metallurgical process for reuse; making supernatant fluid enter a rear-section precipitation tank, adding a second neutralizing agent and a coagulant, discharging the supernatant fluid after the supernatant fluid meets the standard, and concentrating, dehydrating, drying and crushing rear-section sludge primarily comprising a calcium salt component to obtain a dry sludge base material; uniformly mixing 20 to 60 weight percent of dry sludge base material and 40 to 80 weight percent of auxiliary materials, melting the mixture in a high-temperature furnace after performing agglomeration or palletizing on the mixture, and crushing, grinding and milling the treated mixture to obtain a pre-melted base material of the covering slag; and adding 2 to 15 weight percent of carbonaceous material and 0 to 5 weight percent of bonding agent into the pre-melted base material of the covering slag, and then palletizing, drying and sieving the mixture to obtain the finished product of the covering slag.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of stainless steel cold-rolling pickling wastewater, and in particular relates to a method for preparing mold slag for casting by using the rear-stage sludge produced by the chemical reduction-stage precipitation process to treat stainless steel cold-rolling pickling wastewater as raw material . 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-precipitatio...

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Problems solved by technology

[0009] The purpose of the present invention is to provide a method of using stainless steel cold-rolling pickling wastewater to prepare casting mold slag, so as to solve the high cost of stainless steel pickling and cold-rolling sludge in the prior art, which is difficult to use and easy to produce during the process. In order to solve the proble

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