Working principle and characteristics of 4 kinds of gas flow ultrafine mill!

Air comminution is one of the commonly used superfine comminution methods of Z, which is widely used in the superfine comminution or fine comminution of materials in non-metallic ore, medicine, chemical industry, metallurgy and other industries. It has the characteristics of fine particle size, narrow particle size distribution, smooth particle surface, regular particle size, high purity and high activity.

At present, the commonly used industrial air pulverizing equipment mainly includes: flat air pulverizing machine, circulating pipe air pulverizing machine, jet air pulverizing machine, fluidized bed air pulverizing machine.

1

Flat air mill

Flat air mill, also known as disc air mill, was successfully developed by Fluid Energy company in 1934. It is the earliest and most widely used air mill in industry.

The performance characteristics of

Advantages: simple structure, convenient operation, easy disassembly, cleaning, maintenance, and automatic grading.

Disadvantages: when the speed of the material is higher, with the high speed movement of air flow and the inner wall of the grinding chamber will produce violent impact, friction, shear action, resulting in the wear of the wall of the grinding chamber, and cause the pollution of the powder, especially for the material with high hardness (such as silicon carbide, silicon oxide), wear more serious.

The inner wall of the crushing chamber should be made of super hard and high wear-resistant materials. Such as corundum, zirconia, superhard alloy and so on. Flat air mill is not suitable for superfine grinding of superhard and high purity materials.

2

Circulating tube air mill

Circular tube air mill, also known as vertical annular jet air mill, also has internal classification. It can be divided into equal circular section and variable section circular tube air mill. JOM series (also known as O-type) variable cross section circulating tube air mill is the most widely used one.

The performance characteristics of

Advantages: the host structure is simple, easy to operate; Crushing at the same time with automatic grading function; Host equipment small volume, large production capacity; Product fineness is good, can be up to 3~0.2μm.

Disadvantages: the erosion and abrasion of the inner wall of the pipe by air flow and material is too serious, so it is not suitable for the refinement of materials with higher hardness. The grinding efficiency is low in all kinds of air mill, and the energy consumption is high.

3

Counter jet jet jet mill

Jet jet mill, also known as reverse jet mill, is a kind of material in the supersonic flow of their own collision to achieve ultrafine grinding device.

The performance characteristics of

Advantages: large production capacity, avoid the wear of particles on the tube wall and the pollution of the tube wall material on the powder particle, can produce high hardness of the material ultrafine powder.

Disadvantages: complex structure, large volume, high energy consumption, gas-solid mixed flow on the comminution chamber and pipeline still have some wear.

Jet jet jet mill uses the relative movement of the airflow, particles from the first impact on each other, reduce the wear of the tube wall and the pollution of the product, can process hard materials.

4

Fluidized bed airflow mill

Fluidized-bed collision airflow crusher is a combination of the principle of jet and the expansion gas jet flow in the fluidized bed, mainly reflected in energy saving, strong processing capacity, small wear, compact structure, small volume, less temperature rise and other aspects, can be regarded as the current Z advanced model.

(1) Working principle

Material through the valve into the bin, spiral material into the grinding room; Air is sprayed into the grinding chamber through the reverse nozzle to fluidize the material.

The accelerated materials meet at the intersection of the nozzles, where the particles collide, rub, shear and smash.

The pulverized material is conveyed to the turbine ultrafine classifier by updraft, the fine powder products are discharged through the outlet, the coarse particles are returned to the grinding chamber along the wall, and the tail gas is discharged into the dust collector.

(2) Performance characteristics

Advantages: high crushing efficiency, low energy consumption: the airflow particles are multi-angle collision, the force is large, the force of the powder is complex, the external energy is fully absorbed by the powder, the jet power loss is less; By combining the principle of fluidized bed with the horizontal turbine superfine classifier, the fine material can be discharged in time and the energy loss caused by the overcomminution of fine powder can be reduced. Compared with disc air mill, the average energy consumption is reduced by 30~50%. High crushing efficiency, low energy consumption.

Light wear, less pollution: from the first impact, the powder is mainly collision with each other, less impact on the outdoor wall.

Small volume and small floor area: on the premise of the same production capacity, the volume and floor area of fluidized bed collision airflow mill can be reduced by 10~15% and 15~30% than that of disk airflow mill.

High degree of automation, low noise, large production capacity, suitable for large-scale industrial production.

Disadvantages: the particles constantly impact the graded blade at high speed, and the wear of the graded blade is still very serious when producing super hard powder particles. Application: high hard materials, high purity materials, refractory laminated non-metallic ore, heat sensitive and dense porosity materials, etc.