The Classifying Principle and Application of Mineral Processing Process

Classifying is the process to divide the particle group into two or more granularity grades according to the different settling velocity of particles in the moving medium. The medium can be water or air.

The settling form of particles in the grading equipment generally depends on particle concentration. The smaller concentration belongs to free settling classification, and the larger concentration belongs to interference settling. When classifying accuracy is required higher, it is inadvisable to adopt interference setting. The accuracy of the classification is also influenced by particle density and shape, besides particle size.

The chief applications of classifying in ore dressing plants:

1. The preparation operation before gravity separation, for example the shaking table, in order to grade raw materials and reduce the influence of particle size to the separation process.

2. Work together with grinding machines, to control product granularity, timely separate the qualified ground products out and decrease over crushing.

3. Deslime and dewater the raw ore or products.

4. Divide the raw materials into different grades, to cater to different uses.

Classifying equipment can be divided into the following categories:

1. The hydraulic classifier, such as the yunxi-type hydraulic classification box, sieve-plate-type hydraulic classifier. Classifiers in this category are mainly used in the classifying operations before gravity separation, and also used in desliming.

2. The mechanical type classifier, such as spiral classifier. This kind of classifier is mainly to cooperate with grinding machines and is used in the preliminary classification, check classification and controlling classification in ore grinding.

3. The centrifugal classifier, such as hydraulic cyclone. It is mainly applied to the classification, desliming and dewatering of fine materials.