A Detailed Explanation of the Grinding Process of Ore

Grinding is the continuation of the ore crushing process. In the ore beneficiation industry, other than a few types of useful sand ores with high single separation degree that do not need grinding, powder grinding is almost indispensable, and the wet type metallurgical plants, cement plants and many other plants that processing non-metallic useful minerals also need powder grinding.

In the ore grinding process, the most widely used machine is cylinder ore grinding mill whose grinding process goes like this: materials are sent to the continuously rotating cylinder in which there are a certain amount of grinding bodies with different shapes, like balls, rods, short columns, large ores and gravels. When the barrel rotates with a certain speed, these grinding media will be pushed to produce impacting and grinding force to grind the materials. For this reason, the crushing force of cylinder grinding mill comes from the external force that are exercised to the grinding body and transmit the crushing force to the materials to be grinded, and the grinding body is called grinding media and this grinding process is called media grinding.

Generally speaking, grinding is to get fine particles or super-fine products. Other than cylinder ore grinding mill which can also be called media mill, the grinding force of some machines can be directly put on the crushed materials to get products with fine granularity, so this also belongs to the grinding field, such as Raymond mill, colloid mill and air-flow mill. The ore grinding process directly influences the technical indexes of the ore beneficiation plant, for example, the weak single separation degree of useful minerals will reduce the grade of concentrate and the recovery rate; or over crushing or over grinding will not only increase the consumption of electricity and steel, but aggravate the beneficiation process and reduce the beneficiation index.

The consumption of power and metal in the ore grinding process is huge, and the usual electricity consumption is about 2×107~8×107J/t, accounting for 30%~75% of the total electricity consumption of the ore dressing plant, and even for 85% in some plants. The consumption of grinding media and lining boards is sometimes as high as 0.4~3.0kg/t. In addition, the infrastructure investment and maintenance costs of the grinding process are also very high.

According to the fineness differences of the final products, the ore grinding process can be divided into: (1) coarse grinding: the granularity of the final products is 0.15~3.0mm; (2) fine grinding: the granularity of the final products is 0.02~0.15mm; (3) superfine grinding: the granularity of the final products is small than 10um and even 0.05~1um.