1. Determination of the number of broken sections â–¼Table 1 The relationship between the maximum grain size of ore and mining methods The final product particle size depends on the subsequent grinding and beneficiation process requirements. The ball mill has a suitable feed size of 10-15 mm and a Raymond mill of 15-35 mm. Due to the high power consumption of the grinding operation, the particle size of the final product should be reduced as much as possible during the design. Especially for the production of large-scale crushing and grinding process, the economic benefits of reducing the feed size of the mill are greater. â–¼Table 2 Fraction ratio range of various crushers under different working conditions â–² Figure 1 Common non-metallic ore crushing and screening principle process Source: Non-metallic mineral processing technology and application manual, the author: Zheng water Lin, Yuan Jizu, metallurgical industry publication edited: Powder Technology Network VDE Injection Open End Spanner Injection Open End Spanner,Insulated Open End Spanner,10000V Open End Spanner,Vde Open End Spanner Shanghai Countool In't Trading Co.,ltd , https://www.countool.com
The crushing section is the most basic unit of the crushing process. Different crushing stages and different combinations of crusher and sieve have different crushing and screening processes. The number of fracture stages required depends on the maximum degree of bulk in the feedstock and the desired final crushed product size, as well as the crush ratio that can be achieved for each fracture section.
The maximum particle size of the ore is related to deposit conditions, mine size, mining methods and scraping equipment. See Table 1 for general reference.
The total crushing ratio of the conventional crushing process ranges from 10 to 140. The crushing ratio range of various crushers under different working conditions is shown in Table 2.
It can be seen from Table 2 that it is difficult to achieve the purpose by using a section of crushing, and even if the maximum crushing ratio is up to 140, the three-stage crushing can be completed. Therefore, the second or third stage crushing is usually used before the general grinding operation. When the feed size is less than 300mm, two stages may be taken. In special cases (the ore size is less than or equal to 150mm or the mill feed size is coarse), a section of crushing may also be used, such as a double chamber roll crusher.
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2. Determination of pre-screening and inspection screening
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(1) Pre-screening
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Pre-screening is to pre-screen the qualified grain grade before the material enters the crushing section to reduce the amount of material entering the crusher and increase the crusher's production capacity; at the same time, it can prevent the material from being over-smashed; The impact of machine work. Therefore, the application of pre-screening is mainly determined by the content of fine fraction in the ore. The higher the fine fraction content, the more advantageous it is to use pre-screening.
From a technical and economic point of view, it is usually cost-effective to use pre-screening in the crushing process. However, the use of pre-screening requires an increase in the height of the plant. Therefore, when the crusher has a large processing capacity, it is not necessary to provide pre-screening for the convenience of configuration.
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(2) Inspection screening
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The purpose of screening is to control the particle size of the crushed product and to maximize the production capacity of the crusher. Because all kinds of crushers have a part of coarse-grained materials larger than the width of the discharge port, it is beneficial to improve the crushing efficiency and better utilize the crusher's production capacity by checking and screening the unqualified grain size back to the crusher.
However, inspection and screening will complicate the equipment configuration of the crushing workshop and increase the investment. Therefore, inspection and screening are generally only used in the last crushing section.
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3, commonly used crushing and screening process
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In the processing of non-metallic minerals, the commonly used crushing and screening process is a two-stage open circuit and a two-stage one closed circuit process. Quartz, feldspar, limestone, calcite, wollastonite, kaolinite, talc, etc. mostly use a two-stage crushing process.
In some special cases, some special crushing processes can also be used. For the treatment of extremely hard ore and very large-scale processing plants, in order to reduce the crushing ratio of each section and increase the total crushing ratio, a three-stage crushing process can also be considered; when a small-scale processing plant with a smaller ore size can be considered for a section The crushing process. When the ore content of the ore exceeds 5%-10% and the water content exceeds 5%-8%, the fine-grained grade will stick to agglomerate, which deteriorates the production conditions of the crushing process, such as causing blockage of the crusher chamber and the screening machine. Equipment accidents, etc., should be added to the crushing process.
Technology | Non-metallic ore crushing and screening process is designed to save half of the electricity bill!
The basic purpose of crushing and screening is to achieve a certain size requirement for bulk materials with certain properties. Depending on the nature of the material (especially the maximum particle size and hardness) and the requirements for the particle size of the broken product. There are many types of crushing and screening processes, and there are many options for equipment.