(1. China university of mining and technology, Beijing100083; Sinoma International Xianyang Nonmetallic Mineral Research and Design Institute, Xianyang, Shaanxi 7 1202 1)
2/kloc-0 Since the beginning of the 20th century, with the rapid growth of product output and the improvement of product quality requirements in related industries such as paper-making, plastics, rubber, coatings, ceramics, etc., the output of ultrafine powder of nonmetallic minerals in China has increased at an average annual rate of more than 10%, and the total output of various ultrafine powders in 2006 has exceeded 500× 104t. Driven by strong market demand, the processing technology and equipment of non-metallic mineral ultrafine powder have also made remarkable progress. This paper summarizes the development status and latest progress of superfine grinding and fine particle classification technology and equipment for nonmetallic minerals in China [1 ~ 13].
Non-metallic minerals; Ultrafine grinding; Fine grading.
Author's brief introduction: Zheng Shuilin, male, born in 1956, is a professor and doctoral supervisor of School of Chemistry and Environmental Engineering, China University of Mining and Technology (Beijing), and has been engaged in teaching and research of mineral processing and deep processing of nonmetallic minerals for a long time. E-mail :shuilinzh@yahoo.com.cn.
Li Guo, male, born in 1955, is a senior engineer. He is currently the chief engineer of Xi 'an Engineering Company of Sinoma Group and the editor-in-chief of China Gemstone magazine. 1982, has been engaged in the research and development of non-metallic mineral processing and ultra-fine deep processing technology.
The manufacturing of industrial ultrafine powder processing, ultrafine grinding and fine classification equipment in China began in the late 1970s and early 1980s. Up to now, the development of superfine grinding technology and equipment in China has gone through three stages. From the early 1980s to the mid-1980s, foreign technology and equipment were mainly introduced. During this period, domestic superfine grinding technology, equipment manufacturing and technology have just started, and many aspects are basically blank. From the mid-1980s to the mid-1990s, the introduction of foreign technology and equipment was synchronized with domestic imitation and development. Generally speaking, China's ultra-fine grinding equipment system and ultra-fine grinding technology were formed and developed during this period, and the main manufacturers of ultra-fine grinding equipment were basically established during this period. After the mid-1990s, it entered the stage of independent development and manufacturing, supplemented by introduction. Most of the ultra-fine powder processing plants established during this period adopted domestic technology and equipment. Since 1996, the number of superfine grinding technologies and equipment with independent intellectual property rights or invention patents has increased significantly compared with the previous 10 year, and the comprehensive performance of equipment such as processing capacity, energy consumption per unit product, wear resistance, process matching and automatic control has been significantly improved, and the gap with the comprehensive performance of foreign advanced technologies and equipment has gradually narrowed.
First, ultrafine grinding
At present, the ultra-fine grinding method used in industry is mainly mechanical method. The main equipment types are jet mill, high-speed mechanical impact mill, stirring ball mill, grinding stripper, sand mill, vibration ball mill, drum ball mill, planetary ball mill, tower mill, cyclone autogenous mill, high-pressure roller mill, high-pressure water jet mill, colloid mill and so on. Among them, air mill, high-speed mechanical impact mill, cyclone autogenous mill and high-pressure roller mill are dry ultrafine grinding equipment, grinding stripper, sand mill, high-pressure water jet mill and colloid mill are wet pulverizers, and stirring ball mill, vibrating ball mill, drum ball mill, planetary ball mill and tower mill can all be used for dry and wet ultrafine grinding. Table 1 gives the crushing principle, feed particle size, product fineness and application scope of the above superfine crushing equipment.
There are several types and dozens of specifications of jet mills, such as flat (disc) type, circulating tube type, fluidized bed reverse jet type, rotary jet type or cyclone type (Figure 1). These jet mills are mainly used for ultrafine grinding of nonmetallic minerals such as talc, graphite and wollastonite.
Mechanical impact or rotary impact ultra-fine pulverizer is a kind of ultra-fine pulverizing equipment widely used in domestic non-metallic mineral industry, which is widely used in ultra-fine pulverization of coal-series kaolin, calcite, marble, chalk, talc, pyrophyllite and other medium-hardness non-metallic minerals. Fig. 2 shows a mechanical impact grinder for ultrafine grinding of nonmetallic mineral fillers and pigments.
Table 1 Types and Applications of Ultrafine Grinding Equipment
Figure 1 air flow pulverizer
(a) horizontal disc type air flow pulverizer; (b) Circulating pipeline air flow pulverizer; (c) The structure of fluidized bed reverse jet airflow pulverizer; LHY cyclone airflow pulverizer; JFC jet mill
Medium and ultra-fine mills include stirring ball mill, vibrating ball mill, rotating cylinder ball mill, planetary ball mill and grinding stripper, tower mill, sand mill, etc. According to the different stirring mechanism, there are several types of stirring ball mills, such as shaft rod type, disk type, spiral type and rod-disk composite type (Figure 3). This stirred ball mill has been used for ultrafine grinding of kaolin, heavy calcium carbonate, mica and talc. Ultra-fine vibration ball mill has two models (Figure 4), which have been used for fine grinding and ultra-fine grinding of nonmetallic minerals such as graphite, timely and calcite. The drum ball mill used for superfine grinding is characterized by its large diameter (Figure 5). Ball or steel segment is used as grinding medium, which often forms a closed-circuit grinding operation with the classifier in production. This dry closed-circuit ball mill-classifier is widely used in the production of superfine heavy calcium carbonate. There are mainly 20 L, 80 L, 300 L, and 500 L skin grinders (Figure 6), which are configured in series with multiple stages for continuous wet grinding. Since 1994, they have been used in the wet ultrafine grinding production line of coal-series kaolin and heavy calcium carbonate. There are mainly two types of sand mills (Figure 7), horizontal and vertical, which are mainly used for superfine grinding and dispersion of pigments, heavy calcium carbonate and kaolin.
Fig. 2 Mechanical impact (rotating) superfine pulverizer
LHJ mechanical pulverizer; (b) CM5 1A superfine pulverizer; (c) JCF 1000 impact pulverizer.
Fig. 3 stirred ball mill
(a) CYM continuous stirring mill; (b) LXJM superfine mixer; (c) Vertical spiral stirring mill (tower mill)
Fig. 4 Ultra-fine vibrating ball mill
(a)MZD single drum vibration mill; (b)MZ double-tube superfine vibration mill
Figure 5 Ball Mill
Fig. 6 BP peeling machine (300 L, 500 L)
Figure 7 Grinding machine
(a)SEM horizontal sand mill; (b)FSW-40 horizontal bar pin grinder
Roller mill and roller mill are equipment that uses grinding (extrusion) and friction to crush materials, and then configures fine classification equipment to produce ultrafine fillers and pigments. At present, the main models are VRM roller mill, roller mill and ring roller mill (Figure 8).
Fig. 8 Rolling machine and rolling machine
VRM roller mill; (b) a roller mill; (c) HLM internal classification centrifugal ring roller mill
High-pressure jet mill or ultra-fine peeling homogenizer is a kind of wet crushing equipment which uses the strong impact of high-pressure jet (20 ~ 60 MPa) and the cavitation effect of sudden decompression to crush materials due to impact and explosion (Figure 9). This equipment has been applied to the fine crushing and superfine crushing of mica and kaolin, as well as the dispersion and depolymerization of titanium dioxide pigments.
Fig. 9 CYB high pressure homogenizer
(a) outline drawing; (II) Working principle
Figure 10 JM series colloid mill
Colloid mill is a kind of equipment that uses the relative motion of a pair of fixed grinding bodies (stator) and a high-speed rotating grinding body (rotor) to generate strong shearing, friction, impact and other forces, so that the processed material passes through the gap between the two grinding bodies and is effectively crushed and dispersed under the action of the above forces and high-frequency vibration. There are three kinds of colloid mills made in China: JTM, JM and DJM, vertical, vertical and horizontal (Figure 10). At present, it is mainly used for processing colloidal graphite and dispersing paint pigments.
Second, the fine classification equipment
In the process of ultrafine grinding of non-metallic minerals, in addition to ultrafine grinding operation, subdivision operation must also be configured.
According to the different classification media, fine particle classifier can be divided into two types: one is dry classifier with air as the medium, mainly rotor (turbine) air classifier; The second is the wet classifier with water as the medium, which mainly includes superfine hydrocyclone, horizontal spiral centrifuge and settling centrifuge. Table 2 lists the performance and application of main domestic fine classifier.
Table 2 Performance and application of main fine classifiers
Figure 1 1 shows the main dry fine classifier in domestic industry at present. These dry fine particle classifiers are basically matched with the corresponding mechanical impact superfine pulverizer or air jet pulverizer, and their grading granularity can be adjusted in the range of d973~20μm m ... Depending on the classifier specifications or sizes, the production capacity of a single machine varies from tens of kilograms per hour to about 7000kg per hour.
Figure 1 1 Main Fine Separator
QF 5A micro classifier; (b) FQZ superfine classifier; (c) MSS fine classifier; ATP single wheel classifier; ATP multi-wheel classifier; (f) LHB turbine fine classification device; FJW500×6 superfine classifier
There are two main types of wet classifier: one is hydraulic classifier based on the principle of gravity settlement; Secondly, cyclone classifier based on centrifugal sedimentation principle, including sedimentation centrifuges, such as horizontal spiral centrifugal separator (stage), small-diameter hydrocyclone, LS hydrocyclone, GSDF superfine hydrocyclone, etc. (Figure 12), and the classification granularity can reach 1 ~ 5 microns. ..
Figure 12 Main Wet Fine Classifier
(a) LW(WL) spiral discharge settling centrifuge; D-type spiral discharge settling centrifuge; (c) sedimentation centrifugal classifier; Disc centrifugal classifier; Ultra-fine hydraulic rotating machine; (f) cyclone device
Three. technical progress
Dry processing technology of (1) nonmetallic mineral ultrafine powder.
1. Fine classification technology
Since 1985, the dry classification technology has made remarkable progress. The product fineness d97 of the most advanced fine classifier in 1985 is less than10μ m; 1992 d97 ≤ 6 microns; D97 ≤ 3.5μ m in 2000; In 2002, D97 ≤ 2.5 μ m. Production capacity (d97≤ 10μm, GCC):1985 500 kg/h; 1990 1000 kg/hour; 1995 2000 kg/hour; 4,000 kg/hour in 2000; 7000 kg/hour in 2005.
2. Mechanical impact superfine pulverizer
High-speed mechanical impact pulverizer is the main dry superfine pulverizing equipment, which often works in closed circuit with fine particle classifier, and has the characteristics of large pulverizing ratio and simple process. However, the production capacity of the early high-speed mechanical impact superfine pulverizer was small, and the mechanical impact superfine pulverizer developed in recent years has made great progress in improving its production capacity. For example, LHJ-260 mechanical superfine pulverizer [Figure 2-(a)], when the feed particle size is ≤30mm and the product fineness d97 = 10μ m, the hard kaolinite is superfine pulverized, with the installed capacity of 195 kW and the output of 850 ~1400 kg/. Talc, installed capacity 195 kW, output1200 kg/h; Barite, with installed capacity of 202 kW and output of 2000kg/h; Wollastonite, installed capacity 195 kW, output1300 kg/h; Bentonite, with installed capacity of 202 kW and output of 3000kg/h.
3. Ring roller mill and roller mill
Ring roller mill [Figure 8(b) and Figure 8 (c)] is a small and medium-sized ultrafine grinding equipment widely used in the field of ultrafine grinding of calcite in recent two years. Its characteristics are simple process, large crushing ratio and low energy consumption per unit product. The particle size of the feed is 20mm, and a grading device is installed inside, and the fineness of the product can be adjusted between D978 microns; The single machine output is 600 ~1800 t/h; Energy consumption (d97 =10 μ m)100 kw h/t
Roller mill [Figure 8 (a)] is also one of the main developments of dry ultrafine grinding technology in recent years. This kind of grinding equipment is characterized by large single machine production capacity, and the output of heavy calcium produced by calcite can reach 5 ~10t/h; And built-in classifier, product fineness can be adjusted between d976 ~ 20μ m. ..
(2) Production technology of superfine calcium carbonate slurry
With the rapid development of domestic paper industry and the application of modern paper-making technology, the demand for superfine calcium carbonate slurry is increasing at a rate of more than two digits per year, which promotes the rapid progress of production technology of superfine calcium carbonate slurry. Stirring mill specification: 1995 300 L stirring mill; 500 L stirring mill is about 2000; In 2003, 3000 L vertical stirring mill; 3500~5000 L stirred mill in 2005. Unit capacity (d90≤2μm dry weight): 65438+300 kg/h in 0995, 500 kg/h in 2000, 0/000 kg/h in 2003, and 2000 kg/h in 2005; Energy consumption: 65438+250kw h/t in 0995,180kw h/t in 2000,120kw h/t in 2003 and 90kw h/t in 2005.
The important progress in the processing technology of superfine calcium carbonate slurry is also reflected in the fineness and viscosity of the product: the high-quality special surface coating GCC produced: the solid content of the slurry is 75% ~ 78%; Viscosity < < 350 MPa·s；; ; The maximum particle size is 3 ~ 5 microns, the content of -2μm is ≥97%, and the content of 1μm is ≥ 75%; The average particle size is 0.3 ~ 0.5 μ m.
(3) Ultra-fine grinding technology of ultra-fine calcined kaolin.
Ultrafine grinding is one of the key technologies to produce ultrafine calcined kaolin. Ultra-fine grinding equipment for hard kaolinite in China has developed from BP80 grinding and peeling machine in 1995 to BP300 grinding and peeling machine in 1999, and then to BP500 grinding and peeling machine in 2000. In 200 1 and 2005, CYM3000 and CYM5000 large-scale stirring mills came out one after another. The progress of superfine grinding technology in the production line with an annual output of 1 10,000 tons is shown in table 3.
Table 30,000-ton production line superfine grinding technology progress
(4) Processing technology of needle-like wollastonite powder with high aspect ratio.
The processing of needle-like wollastonite powder with high aspect ratio is one of the important technologies for deep processing of wollastonite minerals. In recent years, TH 1200 mineral fiber pulverizing system developed by Shanxi Taihua Company and ACM-700E impact pulverizer of South Wollastonite Mining Company can process ultrafine wollastonite powder with high aspect ratio above 12. These two kinds of equipment are relatively broken and have low energy consumption per unit product.
Four. conclusion
2/kloc-0: Since the beginning of the 20th century, with the rapid growth of product output and the improvement of product quality requirements in paper-making, plastics, rubber, coatings, ceramics and other related industrial sectors, the output of ultrafine powder of nonmetallic minerals in China has increased at an average annual rate of more than 10%, and the total output of various ultrafine powders in 2006 has exceeded 500× 104t. Driven by strong market demand, the processing technology and equipment of non-metallic mineral ultrafine powder have also made remarkable progress. The future development trend is to improve product fineness (reduce crushing limit), increase single machine output (large equipment), reduce energy consumption and wear (unit product), and stabilize product quality; At the same time, develop high-efficiency, low-consumption and high-throughput classification technology and equipment; On the basis of existing equipment and technology, artificial intelligence technology is developed to automatically optimize the production process configuration and operating parameters according to the characteristics of raw materials and the fineness requirements of products, so as to achieve the purpose of high efficiency, low consumption and stable product quality.
refer to
[1] Zheng Shuilin. Development status and trend of nonmetallic mineral powder industry in China. A Mirror of China Powder Industry Volume II. Beijing: China Building Materials Industry Press, 2006, 88-93.
[2] Zheng Shuilin. Development status of nonmetallic mineral processing industry. China nonmetallic mineral industry guide, 2006 (3): 3-8.
Zheng shuilin, zu zhanliang. Present situation of non-metallic mineral crushing processing technology. China Nonmetallic Mineral Industry Guide, 2006 (Supplement): 3-8.
Zhang Guowang, Huang Shengsheng, Li Ziqiang, etc. Research status and development of ultra-fine stirring mill at home and abroad. China nonmetallic mineral industry guide, 2006 (supplement): 1 19- 123.
Li Sanhua, Zhang Jiabao. Application of CYM-5000L vertical stirring mill in ultrafine grinding of nonmetallic minerals. China nonmetallic mineral industry guide, 2007 (1): 50-5 1.
Liu, Guo, etc. Further discussion on the development and application of new centrifugal ring roller mill. China nonmetallic mineral industry guide, 2006 (supplement): 124- 126.
[7] Sun, Lian, Wang Qingfa. Development of CYM series ultrafine Yifeng mill and its application in nonmetallic processing. China nonmetallic mineral industry guide, 2006 (supplement): 13 1- 133.
Wang, Pan Zhidong, Xie Pingbo, et al. Centrifugal classification of ultrafine calcium carbonate. Journal of Silicate, 2006,34 (8): 927-931.
Jjianming Feng, Yan Guodong. New integrated technology for production of calcined kaolin from coal measures. China Nonmetallic Mineral Industry Guide, 2006 (Supplement): 97-99.
[10] Zhang Mengxian. Present situation and application of wollastonite deep processing in China. China nonmetallic mineral industry guide, 2005 (5): 14- 16.
Sun, Xie Wenhai. Market space for the development of superfine pulverizer. China nonmetallic mineral industry guide, 2007 (2): 44-46.
Present situation and development of ultrafine grinding and fine particle classification technology for nonmetallic minerals in China
Zheng Shuilin 1 Guo Li 2
(1 School of Chemistry and Environmental Engineering, China University of Mining and Technology, Beijing100083; 2 Xiangyang Nonmetallic Mineral Research and Design Institute, Xiangyang, Shanxi 7 1202 1
Abstract: The present situation and latest progress of superfine grinding and fine classification technology and equipment for nonmetallic minerals in China are summarized.
Key words: nonmetallic minerals, ultrafine grinding, fine classification.