1. Mineral properties. The choice of mill type is primarily dependent upon the properties of the material it will be used to process. It is vitally important to match the mill and material characteristics properly.
2. Capacity. The scale of the operation will determine the size of the mill which is required. Throughput or capacity is often given in tons per hour (or kg per hour for small mills). Always check capacities with as many sources as possible as sales information can often be biased to encourage sales.
3. Cost. Obviously cost is an important factor. It is important to consider all the costs beforehand. For an accurate analysis of the economic viability of a mill to be carried out the following costs need to be considered: capital costs of mill (and capital depreciation against the useful life of the mill) capital costs of peripherals, such as feeding and classification and Ore Beneficiation equipment, power supply, etc.; transport costs; running costs for fuel or electricity, labor, etc.; maintenance costs
4. Reduction ratio and final size requirement. This parameter will dictate whether a single mill will be sufficient for final product requirements or if a multi-stage plant will be needed. Generally speaking, the greater the reduction ratio then the larger the likelihood of a multi-stage process will be required.
5. Power requirements and type of power supply. Access to a power supply of suitable capacity is essential. Types of power supply for remote applications are discussed in a later chapter in this section. The power requirement for a given mill will be given in the mill specification document provided by the manufacturer. Specific power consumption (example kilowatt hours per ton) is often quoted and is a good comparative guide.
6. Wet or dry product. Products which can be accepted in a wet state, such as slurries, can be milled wet which will often save power and reduce dust related problems. As a general rule, only tumbling mills are used for wet grinding, although other mills can be used for wet grinding in certain circumstances.
7. Continuous or batch operation. Some mills can be designed in such a way as to enable continuous milling. This is important where the throughput is high, as well as making loading and emptying easier within the process. Some mills will only accept batch loads.
8. Portable or stationary equipment required. Depending on the nature of the operation, the equipment can be sited permanently or can be portable. Portable equipment is useful for operations which move frequently due to the dispersed siting of the raw material or where a mobile milling service is offered.
To sum it all up, the technical terms of a grinding mill is very rigorous. Follow these rules to choose the right type of machine and achieve the expected results.