CN107557575A - Process for treating metallurgical dust and mud waste - Google Patents

Abstract

The invention discloses a process for treating metallurgical dust and mud waste, which comprises the steps of adding 10-25 parts by weight of binder into 75-90 parts by weight of metallurgical dust and mud waste, pressing the mixture into blocks by a pressure forming machine, directly adding the blocks into KR for stirring, controlling the stirring speed to be 40-60rpm when the temperature of molten iron reaches 1250-1500 ℃, controlling the adding amount of the blocks to be 1.5-3% of the weight of the molten iron, and realizing short-process recovery of iron resources and removal of zinc elements, thereby realizing the purposes of effectively treating the metallurgical dust and mud waste, recovering iron in the metallurgical dust and mud and removing zinc. The recovery rate of iron resources can reach more than 95 percent, and the removal rate of zinc can reach more than 95 percent.

Description

A process for processing metallurgical dust and mud waste

technical field

The invention belongs to the technical field of metallurgical waste treatment, and in particular relates to a process for treating metallurgical dust and mud waste.

Background technique

At present, metallurgical waste such as blast furnace gas mud, bag ash, and converter mud is piled up and mixed to form a metallurgical dust-sludge mixture, and the metallurgical dust-sludge mixture is then added to the sintering batch. The sintering and blast furnace harmful substances zinc and alkali metals in the waste are not removed by open circuit, but circulate with the waste in the sintering-blast furnace system, and the content of zinc and alkali metals in the waste continues to increase, resulting in the circulation and enrichment of zinc and alkali metals in the blast furnace , bringing a series of hazards to sintering production and blast furnace smelting. Excessively high content of alkali metal compounds such as K and Na in the dedusting ash will increase the specific resistance of these submicron dust particles, making it difficult to be captured by the electrostatic precipitator. The dust removal efficiency and operational stability of the electrostatic precipitator lead to excessive dust concentration in the flue gas emitted by the electrostatic precipitator and increased energy consumption for device operation.

The content of harmful substance zinc in iron-containing dust and mud is relatively high and cannot be used directly. The zinc in it must be recycled or passivated, otherwise it must be sealed and stacked in a designated site. So far, the developed methods for recovering zinc from iron-containing dust mainly include physical method, wet method and fire method. At present, pyroprocessing is widely used, including rotary hearth furnace technology, rotary kiln technology and shaft furnace (melting) reduction technology. However, there are some disadvantages. The rotary hearth furnace method belongs to direct reduction, which is to make iron-containing dust and sludge into raw pellets through a mill, mixer, and pelletizer, and then make direct reduced iron through a rotary hearth furnace as a raw material for steelmaking. Make use of. At present, metallurgical enterprises in the United States, Germany, Japan and other countries adopt this technology. Domestic Maanshan Iron and Steel, Rigang, Shagang, Laiwu Steel, etc. have built rotary hearth furnaces to process zinc-containing dust production lines by means of domestic independent development or imported key equipment from abroad; the rotary kiln technology is to add a binder to the dust in a continuous production line Make high-strength agglomerates (pellets), dry them on the grate machine (drying kiln), and then enter the rotary kiln at a temperature below 1100°C, complete the reduction reaction for 8-10 hours, and then leave the kiln. At present, enterprises such as VAI and Sumitomo Metal adopt this technology; the shaft furnace (smelting) reduction technology is similar to a blast furnace, and the main processes include mixing, compacting, batching, adding coke to smelting and firing. After reaching the smelting cycle, the pellets are directly supplied to the ironmaking process or the molten iron is directly supplied to the steelmaking process, and the discharged water slag enters the blast furnace slag superfine powder device for processing into cement raw materials. This technology has been popularized and applied in Germany, Japan, India and TISCO (with an investment of 700 million yuan).

Pyrochemical treatment does not match the existing process equipment of iron and steel enterprises, and requires a vast site and hundreds of millions of yuan in construction investment. The investment recovery period is long, the process is relatively complicated, and there are many and long treatment process units; equipment maintenance and operation costs High, for example, the construction of rotary hearth furnace covers an area of 12,000 square meters, with an investment of 300 million yuan, and the construction of a shaft furnace covers an area of 15,000 square meters, with an investment of 700 million yuan; external heat sources are required (gas heating with high calorific value, electric heating, hot air, etc.); Add fuel and have high requirements for fuel and raw materials, fine particle size and high melting point of coal ash; the shaft furnace melting method also requires metallurgical coke, and zinc is still enriched in the furnace cycle.

Contents of the invention

In order to effectively solve the problems in the prior art, the present invention provides a process for processing metallurgical dust and sludge waste, adding waste materials such as zinc-containing dust and sludge, LF slag, steelmaking bulk dust, iron oxide scale and the like to KR (Kambara Reactor) for processing , use the mechanical stirring of KR to make the molten iron vortex, make the molten iron and the dust and mud fully contact, meet the kinetic and thermodynamic conditions of the reduction reaction, reduce the iron and zinc, and zinc gasification enters the flue gas dust removal system for recovery, thereby realizing recovery The purpose of removing iron in dust and mud and removing zinc. The huge cost of new large-scale equipment is avoided, and a new path is opened for processing metallurgical dust and mud waste.

Due to the large particle size of metallurgical dust and sludge waste (slag, iron sheet and other waste materials) and the thinner pipeline of the desulfurization injection feeding device, it is not possible to directly use the existing desulfurization agent injection device for feeding. We mix the waste according to a certain proportion and cool Press it into a ball, and then directly add it to the KR stirring desulfurization tank through the hopper. In the present invention, 75-90 parts by mass of metallurgical dust and sludge waste are added with 10-25 parts by mass of binder, and pressed into agglomerates by a pressure molding machine. When the temperature of molten iron reaches 1250-1500°C, the The hopper is directly added to the KR stirring, and the amount of agglomerates is controlled at 1.5% to 3% of the weight of the molten iron, so as to realize the short-process recovery of iron resources and the removal of zinc.

The metallurgical dust and mud waste includes, but is not limited to: 2-3 types of iron and zinc-containing waste from iron and steel plants such as blast furnace gas mud (ash), converter mud (ash), LF slag, and iron oxide scale.

The binder is: water glass or bentonite.

The pressure of the pressure forming machine is 100-300 tons.

Compared with the prior art, the present invention has the beneficial effect that: the present invention mixes the metallurgical dust and sludge waste with the binder in a certain proportion, forms it through a pressure molding machine, and adds it to the KR stirring to make the molten iron vortex, satisfying the reduction reaction Under the dynamic and thermodynamic conditions, iron and zinc are reduced, and the zinc is vaporized into the flue gas dust removal system for recovery, so as to realize the effective treatment of metallurgical dust and sludge waste, recycle iron in metallurgical dust and remove zinc. The recovery rate of iron resources can reach more than 95%, and the removal rate of zinc can reach more than 95%.

detailed description

Example 1

The agglomerate is composed of the following ingredients in parts by mass:

25 parts of blast furnace gas mud, 25 parts of converter mud, 25 parts of iron oxide scale, 25 parts of water glass.

Mix 3.6 tons of the above-mentioned mixture (180 tons of molten steel, 2% of the mixture), and press it into agglomerates under a pressure of 100 tons through a cold press molding machine. When the temperature of the molten iron reaches 1300 ° C, it is directly added to the During the stirring process of KR, the stirring speed is 40rpm, the recovery rate of iron resource is 95%, and the removal rate of zinc element is 95%.

Example 2

The agglomerate is composed of the following ingredients in parts by mass:

30 parts of blast furnace gas ash, 25 parts of converter ash, 30 parts of iron oxide scale, 15 parts of bentonite.

Mix 3.0 tons of the above-mentioned mixture (200 tons of molten steel, 1.5% of the mixture), and press it under a pressure of 150 tons to make agglomerates through a cold press molding machine. When the temperature of the molten iron reaches 1280 ° C, it is directly added to the During the stirring process of KR, the stirring speed is 50rpm, the recovery rate of iron resource is 98%, and the removal rate of zinc element is 96%.

Example 3

The agglomerate is composed of the following ingredients in parts by mass:

25 parts of blast furnace gas mud, 15 parts of LF slag, 40 parts of iron oxide scale, 20 parts of water glass.

Mix 4.0 tons of the above-mentioned mixture (160 tons of molten steel, 2.5% of the mixture) evenly, and press it into agglomerates under a pressure of 200 tons through a cold press molding machine. When the temperature of the molten iron reaches 1320 ° C, it is directly added to the During the stirring process of KR, the stirring speed is 40rpm, the recovery rate of iron resource is 97%, and the removal rate of zinc element is 97%.

Example 4

The agglomerate is composed of the following ingredients in parts by mass:

35 parts of converter mud, 40 parts of iron oxide scale, 25 parts of bentonite.

Mix 4.5 tons of the above-mentioned mixture (150 tons of molten steel, 3.0% of the mixture) evenly, press and form agglomerates under a pressure of 250 tons through a cold press molding machine, and when the temperature of the molten iron reaches 1450 ° C, directly add it to the During the stirring process of KR, the stirring speed is 60rpm, the recovery rate of iron resource is 97%, and the removal rate of zinc element is 95%.

Claims (4)

1. A process for processing metallurgical dust and sludge waste, characterized in that the metallurgical dust and sludge waste of 75 to 90 parts by mass is added with a binder of 10 to 25 parts by mass, and pressed by a pressure forming machine into Agglomerates are directly added to KR stirring through the hopper. When the temperature of molten iron reaches 1250-1500°C, the stirring speed is 40-60rpm, and the amount of agglomerates added is controlled at 1.5% to 3.0% of the weight of molten iron to realize short-process recovery of iron resources , Remove zinc. 2. A kind of process for processing metallurgical dust and mud waste according to claim 1, characterized in that said metallurgical dust and mud waste comprises iron-containing steelworks of blast furnace gas mud or ash, converter mud or ash, LF slag and iron oxide scale 2 to 3 types of zinc-containing waste. 3. A process for treating metallurgical dust and sludge waste according to claim 1, characterized in that the binder is water glass or bentonite. 4. A process for processing metallurgical dust and sludge waste according to claim 1, characterized in that the pressure of the pressure forming machine is 100-300 tons.