The treatment method of blast furnace slag, the treatment process of blast furnace slag iron

Blast furnace slag can be processed into the following materials by various processes.

In China, blast furnace slag is usually processed into water slag, slag gravel, expanded slag and slag beads. Water slag is the process of placing the blast furnace slag in the hot melt state in water for rapid cooling, and there are two main ways: water quenching in the slag pool or water quenching in front of the furnace. Water slag is used as building materials for the production of cement and concrete, because water slag has potential hydraulic cementing properties, under the action of cement clinker, lime, gypsum and other activators, it can be used as a high-quality cement raw material, which can be made:

Slag Portland cement, gypsum slag cement, lime slag cement, slag bricks, slag concrete, etc. Slag crushed stone is a kind of crushed stone material obtained by excavation, crushing, magnetic separation and screening after the blast furnace slag is naturally cooled or poured into the slag yard to form a relatively dense slag after natural cooling or water cooling in the designated slag pit or slag yard.

As one of the largest waste slags in the metallurgical industry, the effective utilization of blast furnace slag has always been highly valued by the industry and the world. In the past, water quenching was generally used as raw materials for cement and slag bricks. Or it can be crushed into dry slag and sold to rock mineral wool production enterprises as raw materials.

One of these two treatment methods is that the water quenching will consume a large amount of water resources, and at the same time produce sulfur-containing harmful gas emissions, causing environmental pollution. The second is to occupy land resources, and the third is that the added value of the processed products is very low, and in a practical sense, it is not fully utilized. In recent years, great progress has been made in the technology of direct production of rock mineral wool from industrial waste hot melt slag, that is, the one-step production process.

Through the industrial upgrading and recycling of industrial waste residue, it is in line with the national energy conservation and emission reduction policy, and the added value of waste residue has been greatly improved, which has very considerable development prospects. The products produced by this one-step production technology fully meet the technical requirements of modern rock mineral wool production. Its superiority is incomparable to the modern cupola rock mineral wool production process, and it will occupy a large market in the field of rock mineral wool in the next few years.

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The blast furnace slag iron treatment process generally includes the following steps: 1Separation of molten iron and slag:

When the blast furnace charge melts at high temperatures, it produces molten iron and slag. First of all, it is necessary to separate the molten iron and slag, and generally use the tilting iron mouth or rotary iron mouth for separation. 2.

Treatment of slag: Slag refers to the iron-free part of the blast furnace charge, which is mainly composed of minerals, fuel ash, flux, etc. The treatment of slag generally includes cooling, crushing, magnetic separation and other steps.

First, the slag needs to be cooled, then the slag is crushed into small particles by a crushing plant, and finally the iron minerals in it are separated by a magnetic separation plant. 3.Treatment of molten iron:

Molten iron refers to the iron-containing part of the blast furnace charge, which is mainly used to produce steel. The treatment of molten iron generally includes steps such as desulfurization, dephosphorization, and decarburization. Among them, desulfurization is generally carried out by adding oxidant or oxygen; Dephosphorization is generally carried out by adding phosphate; Decarburization is generally carried out by adding oxidants or oxygen.

4.Comprehensive utilization of molten iron and slag: The treated molten iron and slag can be comprehensively utilized.

Molten iron can be used to produce steel, while slag can be used to produce water mud, roadbed materials, etc. In addition, slag can also be used in mine backfilling, soil improvement and other fields. In short, the blast furnace slag iron laughing punch treatment process is a complex process, which needs to be adjusted and optimized according to the specific situation to improve resource utilization and economic benefits.

Slag gravel can replace natural stone in our country for highways, airports, foundation engineering, railway ballast, concrete aggregate and asphalt pavement, etc., can be used for: the preparation of slag gravel concrete, application in weak foundations, asphalt paved with slag gravel as the base material is bright and anti-skid performance, but also has good wear resistance, shortened braking distance, used for railway slag can properly absorb the vibration and noise generated when the train is walking. Expanded slag beads are a kind of porous light slag formed by quenching blast furnace slag slag with an appropriate amount of cooling water, and the production methods include injection method, spray method, trench method, and drum method.

It can be used to make light aggregates, to make interior wall slabs, floor slabs, etc., and can also be used for load-bearing structures. Blast furnace slag can also be used to produce slag wool (a white cotton-like mineral fiber obtained by melting in the melting furnace to obtain the melt and then refining it with blast furnace slag as the main raw material), glass-ceramic, calcium silica slag fertilizer, slag cast stone, hot-cast slag, etc.

Blast furnace slag is a type of industrial solid waste. The slag discharged in the blast furnace ironmaking process, also known as blast furnace slag, can be divided into steelmaking pig iron slag, casting pig iron slag, manganese iron slag, etc. In some parts of countries such as China and the Soviet Union, titanomagnetite was used to make iron and discharge vanadium-titanium blast furnace slag.

Depending on the ore grade, tons of slag are discharged for every 1 ton of iron smelted, and the lower the ore grade, the larger the slag discharge.

In 1589, Germany began to use blast furnace slag. After the middle of the 20th century, the comprehensive utilization of blast furnace slag has developed rapidly. Japan's utilization rate in 1980 was 85 percent, the Soviet Union's utilization rate was above 70 percent in 1979, and China's utilization rate was 83 percent in 1981.

The slag discharged during the blast furnace ironmaking process is called blast furnace slag. It mainly contains oxides of calcium, silicon, aluminum, magnesium, iron and a small amount of sulfide. If this kind of waste residue is not used, it will not only occupy a large area of land and waste valuable resources, but also the harmful substances in the waste residue will seep into the soil with rainwater and flow into the rivers, causing pollution and finally endangering human health.

After the gas generator furnace gasifies the raw coal, a solid residue is obtained, which we call slag or ash. Due to the different types of coal and gasification methods, the chemical composition and mineral composition of the obtained slag are different, but its chemical composition is mainly composed of silicon, aluminum, iron, calcium compounds, and all contain a small amount of magnesium, titanium, potassium, copper, phosphorus and other compounds and trace amounts of cyanide. The main forms in which they exist are salts, aluminosilicates, oxides, and sulfates.

The chemical composition of several cinders is listed in the table below.

The slag itself has little or no hydrocementitious properties, but it participates in the chemical reaction of calcium hydroxide or other hydroxides in the presence of water after grinding, especially under steam curing conditions. and to produce compounds with hydraulic cementing properties. Therefore, it can be used as a building material, often used in the production of cinder or slag concrete large samples, etc., and can also be used for road repair or as insulation and sound insulation materials in houses.

Category Silicon Dioxide Aluminum Oxide Ferric Oxide Calcium Oxide Magnesium Oxide Sulfur Trioxide Burning Vector 1 2 - 3 4 5 - There are still some rare metals left in the slag, according to historical records, from 1896 onwards, germanium, barium, uranium and other components of the slag.

The slag of the furnace generally contains 10-20% carbon. The coal was treated by roasting, leaching, purification and reduction technology, and the test results showed that the selenium ** rate was 90 09%, and the selenium powder grade was 99 5%. Selenium residue roasting leaching selenium is generally derived from the electrolytic anode mud of copper, lead and nickel, acid sludge produced by sulfuric acid and the washing of pulp produced.

If the carbon-containing combustibles in the slag are not used, it is not only a serious waste of national resources, but also has a bad impact on the comprehensive utilization of the slag, so in some cities, the slag with high carbon content is made into domestic coal bricks, and then it is burned again, on the one hand, the coal heat energy is fully improved, and on the other hand, the slag can be fully utilized.

Because slag is a porous alkaline substance, it can also be used as a filter material in wastewater treatment system for pretreatment of wastewater such as degreasing and removing solid impurities.

The production of blast furnace slag varies with the smelting technology and the grade of the ore. Blast furnace slag is a silicate material. It has stable chemical properties, and has the characteristics of anti-wear, water absorption, etc., can be widely available, the application of blast furnace slag in China attaches great importance to the utilization rate of blast furnace slag in the United States, Britain, France, Japan and other countries has reached 100%, and even there are many companies and factories specializing in blast furnace slag commodities.

The utilization rate of blast furnace slag in China has reached more than 85%. In order to adapt to different uses, blast furnace slag can be processed into several main products such as water slag, slag crushed stone and expanded slag.

1. Water slag: It is to quench the blast furnace slag in the molten state with water or a mixture of water and air; Make it a gritty, vitreous substance. This is also the main method of processing blast furnace slag in China.

There are many specific water quenching methods, and the commonly used ones are the filter tank water quenching process and the stirring tank pumping water quenching process.

2. Slag gravel: It is a kind of gravel material obtained by blast furnace slag in the designated slag pit or slag yard after natural cooling or water cooling to form a dense slag, and then through crushing, screening and other processes. For this purpose, the hot splash method is often used.

In recent years, Germany, France, the United Kingdom, the United States and other countries have mostly adopted the thin-layer multi-layer hot splash method. This method has the advantages of easy operation and high slag density.

3. Expanded slag: It is a porous light slag formed by quenching blast furnace slag with water. For this purpose, it can be produced by spraying method, sprayer trench method, launder method, etc. The newer process is the production of expanded slag beads by the flow cylinder method invented by Canadian slag ****, referred to as "bulging beads".

Blast furnace slag is the waste discharged from the blast furnace when smelting pig iron, when the furnace temperature reaches 1400-1600, the charge melts, the gangue in the ore, the ash and co-solvent in the coke and other impurities that can not enter the pig iron form the slag that mainly floats on the molten iron with silicate and aluminate. The main components in blast furnace slag are CAO, SiO2 and Al2O3.