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...

AI Technical Summary

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 problem of secondary pollution, the cold rolling sludge is classified, recycled and utilized: the sludge in the front stage has high content of heavy metal elements, which can be returned to the metallurgical process for utilization as raw materials; As one of the raw materials for the mold powder required for the molten steel casting production process

Images