SU1730186A1 - Method of charge preparation - Google Patents

Description

of the charge, the mass of the solid phase in the suspension is 50-80%, and the compressed air is supplied by opposing jets.

The essence of the invention lies in the fact that the treatment of lumped materials is proposed to be carried out by a multi-phase flow: a gas-charge mixture supplied under pressure and having high kinetic energy.

The advantages of this technology are due to the fact that such a flow structure completely eliminates particle rebound effects and sandblasting effects, as a result of which the quality and strength of pelletized materials are improved. At the same time, the conditions for pelletizing the charge are improved and the processes responsible for hardening the pellets are enhanced. The mechanism for treating the charge with a multiphase flow is that the particles of moisture and the charge contained in it, in the process of interacting with the initial charge, promote intensive nucleation, since the less wet initial charge intensively coagulates (sticks) on the overwetted water bodies. The other part of this stream intensively processes the embryos and pellets, being introduced into the structure of the latter at high speed. Moreover, the gas-dynamic parameters of the flow (velocity, flow rate and pressure) in this case can be increased, since the overwetted multiphase flow cores possess considerable viscosity, as a result of which the structure of the pellets is less susceptible to destructive dynamic loads.

The advantages of the proposed method include the possibility of its use for the production of pellets and pelletizing of the agglomerate. For iron ore materials, the nucleation process is significantly enhanced and the strength of agglomerated products increases, however, the hardening of the pellets is more intensive, since the moisture content of the charge is higher and the working mechanism of hardening is more productive to increase the strength of pieces of large sizes. At the same time, when pelletizing the charge, the uniformity of the granulometric composition of the agglomerated raw material significantly improves, which has a favorable effect on the subsequent sintering process.

In this case, the seeds are well agglomerated to form granules of sufficiently high strength.

Improving the efficiency of the process is to increase the productivity of the pelletizing process, to increase the strength of the lump materials and to improve the particle size distribution of the finished materials for furnaces and iron ore pellets.

The flow rate of the slurry injected into the compressed air stream should be 1–20% from the mass of the initial charge. In this case, the method of preparing the charge for sintering is most effective. Moreover, the mass of the charge (solid phase) in the water suspension should be 50-80%. In this state, the suspension easily goes along the path, is efficiently sprayed and participates in the process of pelletizing of the charge.

The advantage of the proposed method is the possibility of simultaneous processing of the charge and its wetting with a water suspension prepared from the initial components of the technological process: a wet charge and water. In this case, the system is simplified, since the dehumidification and processing paths are combined.

The degree of hardening of the materials and an increase in the productivity of the process can be further enhanced if compressed air is supplied by opposing jets. In this case, the pressure force of the multiphase flow jet on the materials increases, the speed of movement of the materials and the intensity of the coating process increase.

An example of the method

The wet iron ore batch is fed to the working surface of a disk or drum pelletizer, where it is crumpled in roll mode. At the same time, it douvlates and at the same time is treated with water-based suspension introduced into the stream of compressed air in the amount of 1-20% by weight of the initial charge, and the weight of the solid phase in the suspension is 50-80%. The formation of the water suspension is carried out by installing a jet ejector on the compressed air supply path, at the entrance of which a chute is attached to supply the charge and a nozzle through which a water jet is supplied. The resulting slurry is sucked into the compressed air supply path, where a multi-phase gas-charge stream is formed, which intensively processes and dusts the lumped materials. An additional increase in the strength of the granules can be achieved

compressed air supply by opposing jets.

The experimental data presented in V. 1 was obtained for a dish-shaped pelletizer with a diameter of 0.4 m, in which the moisture content of Teysk iron ore concentrate changed from 6 to 10.5%, and for a drum granulator, the moisture content of the charge in which was 6, five%. The investigated mixtures in any type of pelletizer using this method allow to increase the strength of the granules by 5.6-27.8% and the productivity of the process by 5.9-58.7%.

The optimal amount of water-injected suspension introduced into the compressed air stream should be 1–20% by weight of the initial charge (Table 2). If this amount is less than 1%, then in this case the proposed method will be characterized by the parameters of the prototype method. If the amount of the water retaining suspension is more than 20% by weight of the initial charge, then the processing of materials makes it difficult

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with and is characterized by low indicators. The solids content in the suspension should be in the range of 50-80%. A decrease in this limit leads to a waterlogging of the charge, and an increase in this limit of more than 80% disrupts the process of outflow of the suspension, since its viscosity increases significantly.

Claims (2)

1. A method of preparing a mixture for sintering, including supplying a wet mixture to a pelletizer, pelletizing, dehumidification and processing of materials with compressed air supply, characterized in that, in order to improve the performance of the process and the strength of the granules, the treatment of the charge is carried out with a water suspension introduced compressed air in the amount of 1-20% by weight of the initial mixture, and the mass of the solid phase in the suspension is 50-80%. 2. The method according to claim 1, wherein the compressed air is supplied by opposing jets. Table 1 Note. The data are presented for the amount of water intake suspension equal to 20% of the mass of the initial charge, and the content of the charge in it equal to 50%. Note. Pelting agloshihtu on drum pelletizer; dashes (-) correspond to impaired processing and pelletizing. table 2