Ore dressing is to separate the valuable minerals from the raw materials. Following, let's have a detailed understanding on what preparation should be done before ore dressing. It includes crushing (crushing and grinding), screening and grading, or ore washing.

1. Crushing. Crush the ore with the granularity of 500-1500mm into 5-25mm. It has squeezed crushing, split crushing and breaking in three steps of primary crushing, medium crushing and fine crushing.

2. Grinding. Grinding and impacting is the main way. In this way, the materials are grinded into the size of 10～300μm. The final granularity is determined according to the impregnated granularity of useful mineral and the grading method. The common grinding machines are rod mill, ball mill, autogenous Grinder and so on. 

3. Screening and grading. Screening refers to screen the particle into different size according to the screen mesh, which is used to treat coarse materials. While grading is to divide the materials into different grade based on the medium settling speed, it is suitable for fine particles. Both screening and grading are to separate the materials with proper granularity.

4. Ore washing. In order to prevent the muddy materials blocking the crushing and screening machine, need to wash the ore mineral. If there exists soluble useful or harmful ingredient, also need to wash.