Factors affecting the fineness of grinding

First, the classification and purpose requirements of grinding

1 , dissociative grinding

Dissociative grinding is a preparatory operation in the process, but the quality of the high-rise building mineral products has a great impact on the indicators of subsequent operations. The purpose of such grinding is the grinding of mineral raw materials, so obtained from the most useful minerals to achieve sufficient single crystals from gangue minerals and between dissociated, and the particle size to meet the requirements of the subsequent job. The fundamental basis for the realization of rational grinding is the diversity of the mechanical structure of the ore. The phase interface between the various crystal minerals that make up the ore is a mechanically fragile surface. After the ore is stressed, the fracture behavior first occurs along the fragile surface of the mechanics. . Fall into this category are grinding grinding metal and non-metallic ore before the ore dressing, grinding and other hydrometallurgical leaching before. This method plays an important role in modern grinding, and it also handles the most minerals. Dissociable grinding sorting limited size can not be very thin, also the particle size 10-20 μ m or more.

2 , pulverizing grinding

Such grinding is aimed at crushing materials, and the finer the finer the better. Such as cement, coal mill power plants, pesticides and other chemical raw materials. Such grinding products are generally the final product. The proportion of its treatment is second only to dissociative grinding. The particle size is also above a few microns.

3 , scrubbing grinding

The purpose of such grinding is neither to dissociate the mineral nor to pulverize the mineral, but to expose the ore to the fresh surface to facilitate bonding with the binder and to obtain a good bond quality. Such as the grinding of construction sand, the grinding of cement sand, the wetting and grinding in the metallurgical pellet process. If the grinding is excessive, it will have a negative impact. Such grinding is also a preparation operation, and the quality of the grinding products seriously affects the quality of the products in subsequent operations. The product has the largest particle size.

4 , super fine crush

Finnish professor Hu Ji proposed a grinding product with a particle size range of 10 -0.001mm The so-called ultra-fine pulverization is that the product particle size is finer than that of conventional pulverization, and the product particle size is several micrometers or even below micro. It is mainly used for deep processing of non-metallic minerals.

Second, the nature of the material

1. Mechanical properties of ore

( 1 ) Ore hardness

The hardness of the ore is determined by the bond force between the particles in the crystal. Hardness refers to the property of the mineral against the intrusion of external mechanical forces. The lower the hardness , the higher the grindability , the easier the ore is to be ground . The fineness is relatively well controlled.

( 2 ) Mineral toughness

The toughness of a mineral is determined by the type of crystal bond and the structural form of the unit cell. In general, the toughness of the mineral is small and easy to grind, and vice versa.

( 3 ) Mineral cleavage

Cleavage is a characteristic of minerals. It is a property in which minerals break into a smooth plane in a certain direction under the action of external forces. The presence of cleavage reduces the strength of the mineral. The better the cleavage, the easier it is to grind.

( 4 ) Structural defects of minerals

Minerals are generally complex, and structural defects such as vacancy, dislocation, and addition are often present in the crystal, which also affects the crystal hardness of the mineral. In addition, the rock ore body in nature is also good, and the mined rock mass is also good, and there are different degrees of water. The water in the pores of the rock will enter the micro-cracks like wedges, adsorb on the surface of the rock fissures, reduce the surface energy, and lead to the reduction of the internal binding force of the rock. The effect of water reduction on the mechanical strength of the rock is not to be underestimated.

2 , grinding grain size

Mill productivity and grinding fineness are related to the particle size of the feed.

Third, the machine structure performance

a) Type of ball mill

b) Specifications of the ball mill

c) Ball mill rotation rate

d) structural shape type of the lining

Fourth, grinding process operating parameters

a) grinding concentration

b) grinding media

i. Media size selection

Ii. Initial ratio of medium

Iii. Medium filling rate

Iv. Media structure shape

v. media complement ball system

vi. dielectric material

Vii. medium density

V. Grinding and grading process

Sixth, human factors

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