Silicon powder processing refers to the process of crushing the silicon block (25-80mm) smelted by special process to produce the specified particle size (usually 80-400μm) Range of silica fume processes. At present, the silicon powder processing equipment in the silicon powder plant mainly includes silicon vertical roller mill and rotary silicon grinding mill. This article introduces the comparison between silicon vertical roller mill and rotary silicon grinding mill in the silicon powder plant.

1、 Comparison of the production capacity between the silicon vertical roller mill and the rotary impact silicon grinding mill in the silicon powder plant: a 5t/h silicon vertical roller mill of a company can exceed the design capacity by about 5% under the designed and calibrated production capacity. Especially when the average particle size is>130um, the production capacity can be higher. φ880, theoretically, has a production capacity of 1.5t/h. However, due to the particularity of the silicon block, the wear of the cutter head, the service life and other transmission equipment failures will affect the actual production capacity and start-up time of the rotary silicon grinding milling.

2、 Comparison of the content of fine silicon powder between the silicon vertical roller mill and the rotary impact silicon grinding mill in the silicon powder plant: under the normal operation of the silicon vertical roller mill system, the content of fine silicon powder can be controlled at about 3%. The proportion of fine silicon powder can be controlled below 8% under the condition of long production time and serious wear of grinding roller (high or low fine powder rate is directly related to operation control); According to the impact spinning of a factory φ The production data of 600 model is 10%~15% for 325 meshes and above. It was previously understood that this value may be exceeded in the actual production process of rotary silicon grinding milling.

3、 Comparison of process design between silicon vertical roller mill and rotary silicon grinding milling system of silicon powder plant equipment: the silicon powder production system of silicon vertical roller mill adopts negative pressure production, the air volume is recycled, the continuity is good, and the system design is reasonable. Through nearly 10 years of actual use, the domestic manufacturers have continuously improved the silicon powder processing technology of the system, which has improved the operation and automation of the vertical roller mill, and made the adjustability more simple and reliable. As the silicon powder processing system of the rotary silicon grinding mill is transported under positive pressure, the sealing of the system is not good, the leakage of silicon dust is large, and the continuity is poor, so it needs to be improved. In addition, the overall design is relatively small, with poor buffer capacity, which can not meet the requirements of large-scale silicon powder production. The overall design of the silicon powder processing system for rotary silicon grinding milling is relatively simple and rough, and some dust removal measures are not perfect, which can only be used by some relatively small silicon powder processing enterprises.

4、 Comparison of safety and environmental protection performance between silicon vertical roller mill and rotary silicon grinding mill in silicon powder plant: the overall design of silicon powder processing system of silicon vertical roller mill is relatively reasonable, and the technology of air separation of silicon powder particle size is adopted. In the process of silicon powder air separation, the outlet pipeline of vertical roller mill, cyclone separator, bag filter, etc. are operated under negative pressure, so the leakage rate of silicon powder is very small, and the dust concentration in the plant of silicon powder processing device is very low, There is no phenomenon of silicon dust flying, fundamentally eliminating the possibility of dust explosion in silicon dust space. Due to the adoption of wind separation technology, the content of fine silica fume (aerosol) in the silica fume production system can be greatly reduced, and at the same time, it can prevent silica fume dust from forming local deposits in the equipment, and eliminate the possibility of dust explosion in the silica fume processing system. The air separation system of the silicon vertical roller mill system is a circulating circuit. The pulse back blown nitrogen of the bag type dust remover is used to supplement the nitrogen into the grinding pipeline. The grinding system can realize nitrogen protection operation with a small nitrogen consumption. Due to the small and relatively simple design of the silicon powder production system of rotary silicon grinding milling, the air separation is not used, resulting in serious leakage of silicon powder dust. The dust concentration at the silica fume production site is relatively high, which is easy to cause pneumoconiosis among employees. As the closed nitrogen sealing system cannot be formed in the silicon powder production system of the rotary impact silicon grinding mill, it is easy to lead to the accumulation of silicon powder dust in the system, which makes the silicon dust (aerosol) content in the rotary impact silicon grinding mill or other locations higher, and silicon powder explosion is very easy to occur when the ignition source energy is high.

5、 Comparison of energy consumption and spare parts consumption between silicon vertical roller mill and rotary silicon grinding mill in silicon powder plant: silicon vertical roller mill (calculated by 1.5wt/a): industrial power 80kw.h/t, industrial water 0.2m/t, nitrogen 9.0Nm3-23.0Nm/t, spare parts cost: about 800000 yuan, average spare parts cost per ton 50-60 yuan/t. rotary impact silicon grinding mill（φ660): Industrial power is estimated to be 75~100kw. h/t, circulating water is about 4m/t, nitrogen is about 126 Nm/t, and total consumption of cutter head is about 70t/a.

6、 Comparison of the maintenance of the silicon vertical roller mill and the rotary impact silicon grinding mill in the silicon powder plant: the silicon vertical roller mill is generally overhauled once a month for 2 working days, with a total of 8-12 overhaul days. The cycle of replacement of cutter head and liner plate by rotary silicon grinding milling is<24h. When the quality of the cutter head and lining plate is poor, it can only be used for 3h~4h and needs to be replaced once. It is estimated that 0.5 workday is required for each overhaul, and the total overhaul workday is about 2 workdays, which not only increases the labor cost, but also delays the production progress.

Conclusion: Through the investigation and comparative analysis of the silicon vertical roller mill system and the rotary impact silicon grinding mill system, as well as the communication with the technicians in the organic (polycrystalline) silicon industry, the general view is that the rotary impact silicon grinding mill is not suitable for large-scale silicon powder processing. In addition, according to the selection of mill by Chinese organic (polycrystalline) silicon manufacturers, although the primary investment of silicon vertical roller mill may be higher than that of rotary silicon grinding mill, silicon vertical roller mill are still the ideal choice for most domestic organic silicon (polycrystalline) manufacturers to process silicon powder. HCMilling(Guilin Hongcheng) is the manufacturer of silicon vertical roller mill for silicon powder plant equipment. Our HLM silicon vertical roller mill has been widely used and recognized in the silicon powder plant industry. If you need to purchase silicon vertical roller mill for silicon powder plant equipment, please contact HCM for equipment details.