What are the raw materials for the production of pellets, and is the raw material type of pellets go

1) Iron-containing raw materials: the grade of iron ore concentrate is not less than 64% 65%, and the fluctuation range is generally required to be less than; Specific surface area of concentrate: within the range of 1500 1900cm2 g, the particle size content of less than is greater than 85%; (2) Binder:

In the production of pellets, some minerals and organic substances are used as binders, among which bentonite is the most widely used because of its cheap and good effect, and the amount of bentonite in foreign countries is generally 6 10kg per ton of pellets, which is the amount of concentrate. The particle size of bentonite used for pelletizing is less than 85% and 90%.The addition amount of bentonite in China is generally 2%, that is, 20kg t.

The bentonite used in the production of pellets has certain quality standards, the bentonite used in our factory is a purchased finished product, and the requirements for the main physical and chemical properties are shown in Table 1: Table 1: The main physical and chemical properties of bentonite are shown in Table 1: Si02Al2O3MGOCAOPS Burning Physical Gum, Particle Size (-325 Mesh), Expansion Factor, Refractoriness, Moisture (%), Water Absorption (18 hours), 75 % 151350 600 % (3) Flux:

In the production of pellets, in order to improve the metallurgical properties of pellets and adjust the alkalinity of pellets, fluxes such as dolomite and limestone are often added. Generally, the general requirements for the quality of the flux are: high content of active ingredients, low content of harmful impurities such as sulfur and phosphorus, and appropriate particle size and moisture.

Pellets are another method of fine grinding iron concentrate or other iron-containing powder briquettes. It is a mixture of concentrate powder, flux (sometimes binder and fuel) rolled into green balls with a diameter of 8 15mm (larger for steelmaking) in a pelletizing machine, and then dried, roasted, consolidated and formed to become an excellent iron-containing raw material with good metallurgical properties to supply the needs of steel smelting. The main processes of pellet production include raw material preparation, batching, mixing, pelletizing, drying and roasting, cooling, finished product and ore return processing.

The raw materials for pellet production are mainly concentrate fines and a number of additives, and if solid fuels are used for roasting, pulverized coal or coke powder. These raw materials are prepared after entering the factory, it includes:

1) Mixing of all raw materials;

2) grind the additives to sufficient fineness;

3) Grind the concentrate powder (or rich ore powder) to -200 mesh greater than 70%, and the upper limit does not exceed;

4) crushing the solid fuel to less than;

5) When there is too much moisture in the concentrate powder, it should be dried.

6) After screening, if the particle is too large, it should be crushed and ground again.

The raw materials that have been prepared and processed above are batched on the batching belt; The batched mixture is loaded into a drum mixer and mixed with water together with the ground ore return. The mixed material is then added to the disc ballmaking machine to make balls, and an appropriate amount of water is added when making balls. The green balls are sieved before roasting, and the sieved powder is returned to the balling tray to be re-balled.

When roasting with solid fuel, a layer of solid fuel is rolled to the surface of the green pellet before it is added to the roaster. The green balls thus made are fed to the roasting equipment by a feeder and roasted. The roasted pellets should be cooled, and the cooled pellets are screened and divided into finished ore (>10mm), bottom material (5 10mm), and ore return (<5mm), and the bottom material is directly added to the roaster, and the ore is returned to the ore after grinding (to participate in mixing and pelletizing after "".

At present, there are several main pellet roasting methods: shaft furnace roasting pellets, belt roaster roasting pellets, and chain grate machine rotary kiln roasting pellets. The shaft furnace roasting method was the first to be used, but it developed slowly due to the inherent shortcomings of the method itself.

At present, the belt roaster method is the most used, and more than 60% of the pellets are roasted by the belt roaster method. The chain grate machine rotary kiln method appeared late, but because it has a series of advantages, it has developed rapidly, and it is likely to become the main pellet roasting method in the future.

Taking shaft furnace roasting pellets as an example, there will be some large sticking blocks in the pellets that are cooled down after roasting, which need to be crushed by the lower roller crusher and discharged out of the furnace, and then crushed and screened to obtain finished pellets, and the products under the sieve will become the base material and returned to be re-roasted.

1. Briquetting into balls is generally a process for producing pellets from ash such as converter ash, and it will only be used if it cannot be rolled into balls. The ball can also be roasted. The pellets are all roasted, and there is no need to make balls for sintering, unless it is sintered with small balls.

2. If it is not dried and roasted, then the green balls formed by pressing the dough are the most powerful.

3. For pellets produced normally, the larger the diameter of the pellet, the higher the compression resistance of the finished ball, but the unit compression resistance is actually reduced.

4 is okay, although it is not so produced, and the highest temperature of sintering ignition is still better to 1350.

5. There should not be much difference in the final strength, the roasting mainly affects the strength of the finished ball, the cost of pressing the ball is generally much higher than that of rolling into a ball, and there is no advantage in roasting.

1. Zhanjiang Longteng Logistics Pellet Project.

Including the first self-designed chain grate machine with an annual output of 5 million tons - rotary kiln pellet production line (also the only production line in China that can produce alkaline pellets), which is contracted by MCC North Engineering Technology ****EPC, the pellet products produced are all for Baosteel Luo Ji project and Shaogang as ironmaking raw materials, which will change the situation that Baosteel and Shaogang all need pellets to rely on imports. The project has been successfully commissioned on September 27, 2009.

2. Ezhou pelletizing factory.

It belongs to Wuhan Iron and Steel Mine Liang Digital Industry Co., Ltd., and its pellet project has the world's largest single 5 million tons pellet production line, with a total investment of RMB 100 million in fixed assets, and adopts the international advanced chain grate machine-rotary kiln-annular cooler production process, which is jointly designed by Metso Mining Machinery and Changsha Metallurgical Design Institute in China, and is responsible for the technical director of the foreign party. The production line was completed and put into operation on December 31, 2005.

3. Shougang Pellet Factory.

Shougang Pellet Factory is the first Shengjingli factory in China to pioneer the oxidation pellet production process: chain grate machine-rotary kiln-annular cooler, which has driven the popularization of the domestic pellet production chain grate machine-rotary kiln-annular cooler. After technical transformation and the construction of the second series, the output of oxidation ball production reached 3.3 million tons in 2006.

1 With the continuous exploitation of the earth's resources, the shortage of rich ores must continue to expand the utilization of poor ore resources, and the progress of mineral processing technology can economically select high-grade finely ground iron concentrate, whose particle size is further reduced from -200 mesh (less than -325 mesh (less than. This kind of overfine concentrate is not conducive to sintering, and the air permeability is not good, which affects the improvement of sinter output and quality, but it is very suitable to be treated by pellet method, because the superfine concentrate is easy to form balls, the finer the particle size, the better the spheroidality, and the higher the pellet strength.

2. The shape of the finished ore is different: sinter is a porous lump with irregular shape, while pellet is a regular shape of 10 25mm pellet than sinter pellet with uniform particle size, more micropores, good reducibility, high strength, and easy storage, which is conducive to strengthening blast furnace production.

3. The raw materials suitable for pellet treatment have been expanded from magnetite to hematite, limonite and various iron-containing dusts, chemical sulfuric acid slag, etc.; From the perspective of products, it can not only manufacture conventional oxidation pellets, but also reduce pellets, metallized pellets, etc.; At the same time, the pelletizing method is suitable for non-ferrous metals, which is conducive to comprehensive utilization.

4.The mechanism of consolidation is different: sinter is consolidated by liquid phase, in order to ensure the strength of sinter, it is required to produce a certain amount of liquid phase, so there must be fuel in the mixture to provide a heat source for the sintering process.

The pellets mainly rely on the high temperature recrystallization and consolidation of ore powder particles, and do not need to produce a liquid phase, and the heat is provided by the fuel combustion in the roaster, and no fuel is added to the mixture.

5.The production process is different: the mixing and pelletizing of the sintered material are carried out simultaneously in the mixer, the balling is not complete, and the mixture still contains a considerable number of small particles that are not balled.

In the pellet production process, there must be a special pelletizing process and equipment (pelletizing disc, etc.), and all the mixture will be made into 10 25mm balls, and the small balls less than 10mm should be screened out and re-balled.

The pellet production process is a production process for refining pellets, and pelletizing and sintering are two commonly used processes in the iron and steel smelting industry as iron ore extraction. Pellets are finely ground iron concentrate powder or other iron-containing powders mixed with a small amount of additives, and then rolled into balls by a pelletizing machine under the condition of water wetting, and then dried and roasted to consolidate into spherical iron-containing raw materials with certain strength and metallurgical properties.

Due to the dwindling natural bonanza, a large number of lean minerals are used; The grade of iron ore concentrate powder after fine grinding and beneficiation is easy to increase; The use of excessively fine concentrate powder in sintering production will affect air permeability and reduce yield and quality; The finely ground concentrate powder is easy to pelletize, the finer the particle size, the higher the balling rate, and the higher the pellet strength. To sum up, the pellet production process has been comprehensively developed and popularized after entering the 21st century.

Nowadays, the development of pellet process has expanded from a single treatment of iron concentrate powder to a variety of iron-containing raw materials, and the production scale and operation have also developed in the direction of large-scale, mechanization and automation, and the technical and economic indicators have been significantly improved. Pellet products have also been used in steelmaking and direct reduction ironmaking. Pellets have good metallurgical properties:

Uniform particle size, many micropores, good reducibility and high strength are conducive to strengthening blast furnace smelting.