The mixing and granulation process is a very important part in the sintering production process. Mixing is to carefully mix the components in the batching process, and granulation is to make the material into a mixture with suitable particle size and good air permeability.

1. The purpose of mixing granulation

1.1 Mix the various materials prepared in the batching chamber to obtain a mixture with relatively uniform composition;

1.2 Add the necessary water for the sintering material during the mixing process, so that the sintering mixture is wetted by water;

1.3 Carry out The granulation of the sintered material can obtain a mixture with suitable particle size and good air permeability.

2. The mixing granulation process

2.1 Two-stage cylinder mixing granulation process

Add various materials into the primary mixer according to the proportion, add water and mix well and then enter the secondary mixer to form a suitable particle size. After the secondary mixing, the materials enter the sintering machine for sintering operation.

2. 2 Three-stage cylinder mixing granulation process

All the materials are batched according to a certain proportion in the batching room and enter the primary mixer. After the primary mixer is mixed, the materials enter the second and third mixing for granulation, and the materials after the third mixing are directly transported to the sintering machine.

2.3 Mixing and granulating process with powerful mixer

In the sintering project, with the increase of the proportion of concentrate and the addition of various other iron-containing materials, higher requirements are put forward for the mixing of materials. Therefore, it is necessary to adopt suitable mixing and granulating technology and equipment. Intensive mixers are generally used to replace one-stage drum mixers.

The mixing and granulation process using a High Intensity Mixer can also be divided into two-stage and three-stage. The High Intensity Mixer is generally used as a mixing device for one stage, and a cylindrical granulator is used for the second and third stages.

2.4 HPS (two sections of cylinders and one section of discs) mixed granulation process

HPS mixed pellet sintering is a small pellet sintering process. Iron ore powder, return ore, flux and fuel are mixed with water to form pellets with a diameter of 5-10mm, and a certain percentage of solid fuel is wrapped on the surface of the pellets. , and then sintered. Compared with the ordinary sintering method, the small pellet sintering method increases the process links of strengthening granulation and external rolling of pulverized coal. Enhanced granulation is to add a disc pelletizer between the first and second mixers, and make the mixture into small balls of 5-10mm. The fuel distribution is to add 20% to 30% of the inner blended pulverized coal in the batching room, and then add 70% to 80% of the outer blended pulverized coal after pelleting. The outer blended coal is wrapped on the surface of the green pellets, which can change the sintering process. The combustion conditions of the medium fuel are improved, the permeability of the material layer is improved, the production capacity is increased, and the fuel consumption is reduced.

2.5 MPS method (three-stage cylinder) mixing granulation process

The MPS method is to mix the materials in the first mixer, and granulate the materials into pellets in the second mixer. On the surface of the small ball, it is wrapped and compacted, and the mixture from the three-mixed material directly enters the sintering machine. The process has the characteristics of improving the air permeability of the material layer, increasing the thickness of the material layer, improving the strength of the sinter, improving the utilization factor and reducing the fuel consumption.

3. Mixing and granulating equipment

Commonly used mixing and granulating equipment in the mixing and granulating process are: drum mixer, coal rolling machine, intensive mixer, disc pelletizing machine, etc.

4. Conclusion

In the process configuration of various mixed granulation, the raw material conditions of the sintering plant, the production scale of the sintering machine, and the process configuration of the sintering plant should be combined to determine which process to use. In the engineering design, the appropriate mixing and granulation process configuration is selected according to the specific raw material conditions to improve the output and quality of sintered ore and reduce energy consumption.