For ultra-fine grinding of non-metallic minerals, the choice of grinding equipment is crucial
For the processing of non-metallic minerals, one is to remove impurities and improve the purity of the product; the other is to reduce the particle size of the product to varying degrees. In the process of reducing the particle size of the product, the choice of grinding equipment is very important, which directly affects the utilization rate of minerals, production costs, product quality and economic benefits.
Faced with so many grinding equipment on the market, non-metallic mining companies generally need to consider the following aspects when choosing:
- Raw material hardness
The hardness of raw materials is the basis of equipment selection, and it is related to the investment in many aspects such as equipment mainframe, auxiliary equipment, capital construction investment, operating cost and so on.
If the Raymond mill is used to process ultra-fine quartz powder, a pressurized (hydraulic or mechanical) system is required to apply sufficient pressure to crush. The increase in pressure increases the manufacturing cost and operating cost of the equipment, especially the reliability of the grinding rollers and grinding discs. The performance is greatly reduced, the failure rate of the pressurization system increases, and the equipment shutdown and maintenance costs rise sharply.
- Product fineness and particle shape
Product particle size and its distribution and product particle shape are one of the most basic and important indicators in the industrial application of non-metallic mineral products. Product fineness and particle size distribution depend on the classification equipment, and the particle shape is inseparable from the grinding method.
If the raw materials are non-metallic minerals below medium hardness, such as talc, marble, kaolin, bentonite, feldspar, etc., the product fineness is required to be about 104-38μm (150-400 mesh), and Raymond mill or eddy current mill can be used , Vertical mill, hammer mill, vibration mill, ball mill, roller mill, etc. Under normal circumstances, there is no need to install an additional air classifier.
If the fineness of the product is below 38μm (above 400 mesh), in addition to choosing fine-grained grinding equipment, such as Raymond mill, vertical mill, vibration mill, ball mill, rotary mill, etc., it is also necessary to choose airflow classifier and The mill is matched, otherwise it is difficult to meet the requirements of product fineness and gradation.
When choosing a classifier, in addition to considering product fineness, classification efficiency and unit product energy consumption, it is also necessary to match the mill in terms of processing capacity and air consumption.
For some non-metallic minerals, such as graphite, talc, kaolin, wollastonite, etc., maintaining the flaky or needle-like particle shape helps to improve its application performance and use value. Therefore, when choosing grinding equipment for these minerals, the particle shape must also be considered.
For example, if the ultra-fine powder product requires the shape of a polygonal body, the grinding operation should be avoided as much as possible during the processing, and equipment that produces appropriate extrusion and impact effects should be selected, and it is better to be crushed in multiple stages.
It is impossible to process ultrafine powders with high sphericity requirements by high-speed impact, because particles with high sphericity require grinding processing methods.
What equipment is used to control the fineness and grain shape, whether it is through a one-stage grinding or a multi-stage grinding, and how reasonable the crushing ratio is set for each crushing grinding, etc., greatly affect the total investment.
- Product purity
Many downstream applications have certain requirements for metal oxides such as iron oxide and titanium oxide and whiteness indicators of non-metallic mineral powder products. Therefore, handling impurities is the biggest difficulty in non-metallic mineral processing, and it is also difficult to solve in the total investment. problem.
When selecting mills and classifiers, the wear and material of the equipment must be considered. If necessary, strict isolation measures should be taken at all parts of the equipment in contact with the material. Isolation methods, equipment, insulation materials used and their costs are not a small number, and they all need to be carefully considered.
- Product variety and output
Where possible, it is best to use a process production (process) line, which requires comparison of the optional grinding equipment that can achieve the product fineness, and on the basis of comparison, select a large-scale equipment that can meet the output requirements of a single equipment . Because in general, the fewer production lines, the more convenient it is to manage. Compared with multiple small devices, the unit product energy consumption and production cost of a single large device are lower.
In addition, if there are many varieties of products and one equipment cannot be used for smashing and processing alternately at the same time, it is necessary to consider multiple (sets) of process equipment.
- Energy consumption per unit product
Energy consumption is an important part of product cost. Regarding the choice of energy consumption and equipment, we can consider both the product properties of non-metallic mineral ultra-fine powder and the utilization rate of minerals.
Three factors are involved:
Mineral properties and crushing ratio, crushing method and crushing ratio, crushing method and energy utilization rate.
- Operating cost
Operating costs are often overlooked by investors. According to the system composition and working principle of the equipment, the actual situation of wearing parts, consumable materials and moving parts should be understood in detail, such as: reliability, life, cost, maintenance time, replacement method, degree of automation, knowledge requirements of operators, etc. , So as to determine the choice of equipment and calculate the investment cost.
For example, the nozzle components and clean air supply in the jet mill host must be specifically listed and calculated. The one-time use of the clean air source increases a lot of operating costs.
- Infrastructure investment
The cost of capital construction mainly includes the basic characteristics of the equipment, such as the material characteristics of the excavation foundation, the construction and management of the bearing foundation, the occupied area, the height and span of the plant, and the building materials. For example: the original supply of jet mill is supplied by special equipment compressor, and its basic requirements are high in cost. All these should make investors consider carefully.
To deal with the ultra-fine grinding of non-metallic minerals in actual production, we should try our best to study and adopt a reasonably optimized process. The optimized process proposes and determines the performance requirements of mechanical equipment. The equipment manufacturer can fully meet the process Required equipment. This customized non-standard equipment can obtain the best product performance and economic benefits. Although the investment cost has increased slightly, the overall benefit is far beyond the result of equipment selection.
Taking a step back, the manufacturer’s equipment should be modified to meet its own requirements, and the process requirements should not be easily changed to adapt to the performance of the equipment that has been finalized. It is the best choice to optimize the parameters in accordance with the process and let the manufacturer provide a complete set of equipment, so that the best working condition and the benefits of high-quality products can be obtained.