Method for Harmless Treatment and Recycling of Chromium Slag and Metallurgical Waste

Abstract

The invention discloses a method for innocently treating and recycling chromium residues and a metallurgical waste material. The method comprises the following steps of: preparing balls by taking chromium residues to be treated as a raw material and taking pulverized coal, coke powder, gravitationally collected dust or iron-making washing dust as a reducing agent and an adhesive; preparing compound small balls from the adhesive and the balls by taking the dust in a metallurgical iron-containing waste material as a spherical shell raw material on a sintering production line or a pellet production line; putting the compound small balls separately or together with an agglomerate raw material or a pellet raw material into a sintering machine and sintering the mixture into agglomerate or pellet; and allowing the balls to form a reducing atmosphere in the spherical shell at a sintering or baking high temperature so as to realize the pretreatment of the chromium residues and further putting the agglomerate or the pellet into a blast furnace to treat the chromium residues completely. The conventional sintering and blast furnace treatment are adopted on the premise of not changing the overall oxidation atmosphere of sintering, the chromium residues are treated effectively and the dust in the metallurgical iron-containing waste material is utilized effectively, so that the method is economical, environmentally-friendly and easy to implement.

Description

technical field [0001] The invention belongs to the field of environmental protection treatment of metallurgical ironmaking and chromium slag. Background technique [0002] At present, there are four methods for the harmless treatment of chromium slag: chemical method, physical / chemical method, melting method and solidification / stabilization method, among which the melting method is the most thorough. The melting method is a process of detoxifying hexavalent chromium by adding additives to toxic substances at high temperature. The smelting and harmless treatment technologies of chromium slag mainly include carbon reduction method, sintering method, dry reduction method and cyclone furnace sintering method. [0003] The sinter method is the most thorough method of detoxification because there is a blast furnace method after it. At the same time, because this method is carried out incidentally in the normal production process of the existing equipment of the metallurgical en...

AI Technical Summary

Problems solved by technology

However, the toxic substance hexavalent chromium in chromium slag can only be effectively and thoroughly treated under high temperature and reducing atmosphere

Blast furnace is a high-temperature reducing atmosphere, and sintering is a high-temperature oxidizing atmosphere. It is uneconomical and inapplicable to deal with the toxic substance hexavalent chromium in sintering by changing the overall atmosphere of sintering.

[0013] In addition, the dedusting ash in the metallurgical iron-containing waste is metallurgical waste that can be reused (some heavy metals in the dedusting ash collected by the electrostatic precipitator of metallurgical waste exceed the standard and must be processed and utilized). The ash is directly added to the sintering mixture for recycling. However, due to the poor hydrophilicity and activity of the metallurgical dust removal ash, fine powder will be formed when the temperature rises on the sintering trolley, which makes the sintering air permeability worse. , part of the dust dust fine powder is drawn into the dust collector again by negative pressure, forming a vicious cycle of dust removal, increasing the dust removal load on the dust collector, and having many adverse effects on the sintering process

As far as blast furnace gravity dust is concerned, due to its relatively low carbon content and rather unstable, it cannot be included in the sinter fuel use plan and cannot be used, resulting in waste

[0014] Therefore, it is very difficult to make pellets by using dust removal ash from metallurgical iron-containing waste. The effect of using bentonite or humic acid as a binder is not ideal unless it is used in a large amount, but it will reduce the iron content of the raw material. This is indisputable in the metallurgical industry. reality

The reason is that metallurgical iron-containing waste is clinker after high-temperature firing, which has poor hydrophilicity and activity, is difficult to form into pellets, and has poor strength after pelletization, so it is difficult to meet the smelting requirements.