(1. Beijing Institute of Mining and Metallurgy, Beijing100044; 2. BASF Minerals (Shanxi) Co., Ltd., Shuozhou, Shanxi 036800)

GJ 5×2 large-scale double-tank high-intensity stirring mill is the latest superfine grinding/peeling equipment in superfine material processing in China, and it is also one of the largest equipment in this field in China at present. The equipment adopts innovative technologies such as double impeller agitator, square cross-section double tank, and load start-up mode. The equipment has the advantages of large production capacity, high superfine grinding efficiency, fine product granularity and continuous production. The equipment has novel structure and is convenient for installation, operation and maintenance. This machine has been successfully applied to a kaolin peeling machine of a kaolin company. Under the production capacity of 1.2 ~ 1.5t/h, the fineness of single machine can reach -2 micron 85% ~ 90%, and the fineness of two machines in series can reach-2 micron 94%.

GJ 5×2 large-scale double-groove high-intensity stirring mill; Ultrafine grinding; Calcined kaolin in coal measures.

About the author: Wu Jianming (195 1—), male, researcher of Beijing Institute of Mining and Metallurgy, engaged in the research and development of crushing engineering. Mailing address:No. 1 Waiwenxing Street, Xizhimen, Beijing, 100044.

Cao Yongxin (1970-), male, senior engineer, general manager of BASF Mineral Products (Shanxi) Co., Ltd., mailing address: Pinglu District, Shuozhou City, Shanxi Province, 036800.

I. Overview

In the past 30 years, the research and development of ultra-fine material processing equipment has continued to develop rapidly [1 ~ 8]. This is because: ① Many industrial minerals and materials have high surface energy, rapid chemical reaction, large adsorption capacity, good filling and reinforcing performance, low sintering temperature, high strength of sintered bodies, and unique excellent properties such as dispersibility, rheology, electricity, magnetism and optics, so as to meet special application requirements or produce high-performance and high value-added products. Therefore, all kinds of superfine materials are widely used in modern industry, high-tech industry and new material industry, such as high-performance ceramics, microelectronics and information materials, plastics, rubber and composite fillers, paper fillers and coatings, high-performance pigments and coatings, high-performance lubricating materials, fine abrasives, advanced refractories, fine chemical products, high-grade cosmetics, textile additives, medicines and health products. The rapid growth of demand for superfine materials has promoted the continuous expansion of production scale. (2) With the development of beneficiation technology, especially the progress of fine particle beneficiation method, the effective separation of ≤ 10μm has been realized. This makes the recovery of fine-grained embedded useful minerals and useful components from tailings that were difficult to treat in the past enter the actual production stage, and has been paid attention to because of the depletion and shortage of mineral resources and the increasing depth and breadth of useful mineral recovery and utilization. These new applications or processing requirements require the use of ultrafine grinding, and ultrafine grinding equipment has become an important necessary equipment in this processing field.

Second, the research and development status of stirring mill at home and abroad

(1) Foreign situation

The agitator mill was first invented by Union Process Inc on 1928. The Attritor agitator mill developed by the company in 1980s is still an internationally renowned product. 1939 the U.S. bureau of mines designed and manufactured a device for cleaning mineral surfaces before flotation, which was improved into a USBM vertical stirring mill in the late 1950s and early 1960s, and was used for stripping kaolin and mica and ultrafine grinding bismuth oxide. From 65438 to 0948, DuPont developed a high-speed stirring mill-sand mill, which was mainly used to produce pigments in coating industry, which made the stirring mill develop greatly. In 1950s, Kopper Tower Mill Company of Japan developed a new type of stirring mill-tower mill, which was widely used in the fields of superfine grinding and chemical treatment. In the 1960s and 1970s, the ore outlet device of the stirring mill was improved, and the rotating speed of the agitator was continuously improved. From 1969 to 1972, American Industrial Mineral Processing Equipment Company (IMPEX) invented a patented technology-high-strength ultra-fine stirring ball milling (tabletting) process, and developed FMM double-groove high-strength stirring mill accordingly. The equipment adopts a vertical tank with square cross section, which has the advantages of fast mixing speed, high superfine grinding efficiency, large production capacity and continuous production. Many kaolin companies in Georgia, USA have used this equipment. In 1970s and 1980s, a stirring mill with a disc agitator appeared abroad, which is characterized by a small grinding cavity, a high rotating speed, and a circumferential speed of 8 ~10m/s. The medium filled 60% ~ 80% of the grinding cavity. Due to the small volume of the grinding cavity, the medium quality is also small. Therefore, the agitator not only plays a stirring role, but also plays a grinding role [1].

At present, there are three representative advanced stirring mills in the world, namely Isa mill with disc agitator, VertiMill mill with spiral agitator and Detritor mill with rod agitator [2].

Isa mill * * jointly developed by Mount Isa Mines Lead-zinc Mine in Australia and Netzsch-Feinmahltechnik Company in Germany is a high-energy-density stirring mill, which adopts a horizontal disc agitator, with a disc circumferential speed of 20 ~ 23 m/s and a motor power of 2.6~3 MW. Its largest model is M 10000 and its volume is 10 m3, which is the largest stirring mill in the world at present. At present, 25 Isa mills have been put into use in Australia, South Africa, Kyrgyzstan and the United States. Isa mill is mostly used for regrinding concentrate, and self-grinding can be realized when ore is used as medium. For example, in MacArthur River Mine, the primary autogenous mill discharges 0.8 ~ 1.8 mm particle size as the grinding medium of Isamo mill, and the flotation coarse concentrate is ground from 45μm 80% to 7μm 80%. Isa mill can also replace the closed-circuit grinding of ball mill or tower mill in the fine grinding stage. For example, in Kumtor Gold Mine, the power consumption is less than half of that of regrinding ball mill, and the hydrocyclone and its feeding pump are omitted.

Vertical mill is a tower mill invented by Kubota Tower Mill Company of Japan in 1950. 1979, MPSI Company of the United States purchased the patent of Japanese tower mill, called vertical stirring mill, and applied it to lead-zinc mine, gold mine and other industrial departments. With the merger of enterprises, the vertical mill was owned by Swedala Group in Sweden in the early 1990s and Metso Group in Finland in the late 1990s. The peripheral speed of the spiral outer edge of the mill is about 3 m/s, and the medium is 12 ~ 30 mm steel ball. The allowable feed particle size is coarse, and the product particle size is often between 10 ~ 20 microns, which is mostly used for mineral processing and regrinding. At present, the maximum equipment installation power used is 1 100 kW.

Detritor mill is also a vertical stirring mill manufactured by Metso Group in Finland. The linear velocity at the end of the stirring rod is about 1 1 m/s, and the medium is about 1 ~ 2 mm ceramic beads or sand. The optimal feeding granularity is about 50μm, and the product granularity can reach below10μ m. At present, the maximum installed power of the equipment is 355 kW, and 2 1 set is used in Zinifex Century Zinc Mine in Australia, of which 6 sets are used for regrinding and 5 sets are used for ultra-fine grinding.

(2) Domestic situation

From the late 1980s, China began to introduce and develop various kinds of stirring mills and peelers, mainly including the following.

1. Intermittent stirring mill

On the basis of 200-SL mixing mill of United Technologies Corporation of America, SJ-90 mixing mill and ZJM mixing mill have been developed in China. The main characteristics of the stirring mill are: the tank body is vertical and cylindrical, and it is fixedly installed; The stirrer adopts a round rod-shaped stirring blade; The stirring speed is low, which belongs to low-intensity stirring mill; Wear parts such as tanks and mixers are lined with polyurethane; Circulate materials with a circulating pump to ensure uniform grinding; Use cylinder interlayer or external cooler to cool the material. The ultra-fine grinding efficiency of this kind of stirring mill is low, and the specification is small and medium-sized, which is suitable for small batch production and not suitable for large-scale continuous production. It is an ultra-fine crushing equipment widely manufactured and used in China in the early days.

2.BP(MB) series peeler and GSDM-400 mixer.

It is a high-strength stirring mill, which is used for vertical wet continuous operation of disc agitator. The barrel of BP(MB) series peeler is lined with corundum or polyurethane elastomer, and the agitator is lined with polyurethane elastomer. The installation power of the early product BP80 peeler is 30 kW, the cylinder volume is 0.080 m3, and the total weight is 2.5t It needs 8 ~ 10 units to work continuously in series. Enlarged to MB300 stripper, the cylinder volume is 0.3 m3, the installation power is 75 kW, and the weight of the whole machine is 5 t. When used to treat coal-series kaolin, the output of four sets in series can reach about 1.5t/h, and the product granularity can reach about -2μm 90%. At present, the largest specification is BP 500, the cylinder volume is 0.5 m3, the installation power is 132 kW, and the whole machine mass is12.5t. ..

The structure principle of GSDM-400 stirring mill is similar to that of BP(MB) series peeler. The cylinder body is lined with aviation rubber or corundum, and the agitator is lined with aviation rubber. There are three working modes: external circulation mode, multiple series continuous grinding mode and batch grinding mode. The cylinder volume is 0.408 m3, and the installation power is 30 ~ 45kW. When using -325 mesh Shuozhou coal-series kaolin for ultra-fine grinding test, it can be ground to -2μm 90% at the optimal concentration of 30%, and the treatment capacity is about 260 kg/h [4].

3. Spiral stirring mill

It is a stirring mill with a spiral agitator, with relatively large barrel height and diameter and low stirring speed. It belongs to low-intensity stirring mill and is suitable for rough grinding, regrinding or superfine grinding, wet or dry operation.

4. Large-scale stirring mill with large height-diameter ratio

LXJM-3600 large-scale ultra-fine stirring mill adopts a rod agitator, with a volume of 3.6 m3, an installation power of 250 kW and an overall dimension (length× width× height) of 2.2m× 2.2m× 8.5m..CYM-5000 large-scale ultra-fine stirring mill adopts a polygonal cylinder and a disc agitator, with a volume of 5 m3 and an installation power of 315kW.. The overall dimension (length× width× height) is 2m× 2m×11m. These two mills have come out in recent years, and they have high stirring grinding strength and production capacity.

3. Development and application of GJ5× 2 large double-groove high-strength stirring mill

(A) the basic structure of the equipment

The model number of the developed large-scale double-tank high-intensity stirring mill is GJ5×2, which is mainly composed of tank, motor, reducer, belt drive, isolation net, agitator, electric control cabinet and so on. The tank body consists of two cubic tanks with the same size, the bottoms of which are connected, and the volume is *** 10 m3. One of the two grooves is used for pre-grinding and is provided with a feed inlet; The other one is used for fine grinding and is provided with an isolation net and a discharge port. The tank is filled with 8 ~ 10 t grinding medium with particle size less than 5mm, and the volume of medium and pulp accounts for about 60% of the grinding cavity volume. A set of agitator is arranged in each tank, and a set of driving device is arranged above each tank. The bottoms of the two tanks are respectively provided with a discharge port and a compressed air inlet. The top of the tank body is provided with an exhaust pipe. See figure 1 for the appearance of the equipment after manufacturing.

Figure 1 The first GJ5×2 large-scale double-tank high-intensity stirring mill developed by Beijing Institute of Mining and Metallurgy.

When working, the agitator rotates at high speed, which strongly stirs the medium and pulp, so that mineral particles are strongly ground. The ground pulp first enters the pre-grinding tank from the feed inlet for pre-grinding, then enters the fine grinding tank from the bottom for fine grinding, and finally is discharged from the discharge outlet through the isolation screen.

(II) Main technical performance indicators (Table 1)

Table 1 GJ5×2 Main technical performance indexes of large-scale double-groove high-strength stirring mill

(III) Application effect

The research and design work of GJ5×2 large-scale double-groove high-strength stirring mill began in 1997. 1In July, 1999, the first GJ5×2 large-scale double-groove high-intensity stirring mill was manufactured in the factory of Beijing Research Institute of Mining and Metallurgy, and the factory test was carried out with load, reaching the designed mechanical properties. From June, 5438 to October, 2000 10, the equipment was tested at full load for 72 hours in Pingshuo Kaolin Factory, Shuozhou City, Shanxi Province, which was the predecessor of BASF Mineral Products (Shanxi) Co., Ltd., and achieved the expected technical performance indicators and achieved ideal results. Since May 2002, the equipment has been put into production in BASF Mineral Products (Shanxi) Co., Ltd. ..

1. Process flow and materials

The raw material is coal-series hard kaolinite, which comes from many producing areas and has different properties in long-term production. Raw materials from different producing areas are often mixed together. The raw materials were crushed by a jaw crusher, then dry-milled to -45μm by raymond mill, and mixed with water and sodium hexametaphosphate dispersant in a slurry mixing tank to make slurry with a concentration of about 45%, which was supplied to a stirring mill.

The first GJ5×2 large-scale double-groove high-intensity stirring mill is used for rough grinding, and MB(P) 80 peeling machine is used for fine grinding. After that, GJ5×2 large-scale double-groove high-intensity stirring mills gradually increased, and finally increased to 6. At this time, it is not only used as a rough mill, but also used as a refiner. It adopts a very flexible connection mode, and can connect two, three or one MB(P)80 peeler in series.

2. Single application effect

In May, 2002, the first GJ5×2 large-scale double-tank high-intensity stirring mill was put into use and studied. During the investigation, the feeding speed of GJ5×2 large-scale double-tank high-intensity stirring mill was measured and adjusted every 30 minutes and recorded. Sample the discharged particle size once every 60 minutes, and measure it four times as a batch. The investigation results show that the product granularity of GJ5×2 large-scale double-tank high-intensity stirring mill reaches -2μ m 85% ~ 90%, and the production capacity reaches about 65438 0.5t/h. In the subsequent long-term production, due to different raw materials, the material properties fluctuate and the production capacity also changes. In the case of material grinding difficulties, the production capacity can be maintained at around 1.2 t/h, reaching the design index.

3. The application effect of two groups in series

Due to the successful application of the first GJ5×2 large-scale double-tank high-intensity stirring mill, BASF Mineral Products (Shanxi) Co., Ltd. added several such equipments one after another, and finally reached six. At this time, a very flexible connection mode is adopted, which can be two in series, three in series, or one in series with multiple MB(P)80 peeler.

When two GJ5×2 large two-tank high-intensity stirring mills are connected in series, with the change of raw material properties, the production capacity is 1.2 ~ 1.5 t/h, and the final product particle size is about -2μm 94%. This indicator is the same as that of two series MB(P)80 peeler (each series is connected in series by 1 1, operated by 10, and 1 standby). It can be seen that a GJ5×2 large-scale double-groove high-intensity stirring mill is equivalent to 10 MB(P)-80 pieces.

(D) Advantages of GJ5×2 large-scale double-tank high-strength stirring mill

1. Less equipment and simplified process.

A GJ5×2 large double-tank high-intensity stirring mill can replace 10 MB(P)-80 tablet press, which greatly reduces the number of equipment and simplifies the process. At the same time, the number of operators is reduced, and the labor intensity of the operators is reduced.

Energy saving

GJ5×2 large-scale double-groove high-intensity stirring mill has obvious energy-saving effect. The power of this equipment is only 150 kW, while the power of MB(P)-80 peeler is 30 kW, 10 * * 300kW. Considering their different load rates, the former saves about 30% energy than the latter.

3. Reduce the floor space

At the site where 10 MB(P)-80 peeler is installed, 2.5 GJ5×2 large-scale double-groove high-strength stirring mill can be installed. According to the same production capacity, the former only accounts for 40% of the latter.

Four. conclusion

After in-depth investigation and careful research and design, GJ5×2 large-scale double-groove high-intensity stirring mill was successfully developed. The equipment adopts innovative technologies such as double impeller agitator, square cross-section double groove structure and compressed air load starting mode. This equipment is used to strip calcined kaolin from coal measures of BASF Mineral Products (Shanxi) Co., Ltd. Under the conditions of feed granularity of -45μm and production capacity of 1.2 ~ 1.5t/h, the granularity of a single product can reach -2μ m 85% ~ 90%, and the granularity of two products in series can reach -2μm 94%. The equipment has the advantages of strong production capacity, high superfine grinding efficiency, fine product granularity, continuous production and energy saving. The application of this equipment reduces the number of equipment, simplifies the process, reduces the number of operators, reduces the labor intensity of operators, and reduces the floor space and capital investment. The overall structure and overall dimensions of the equipment are reasonable, which is convenient for installation, operation and maintenance. This equipment is one of the largest ultra-fine crushing equipment in China at present, and it gives full play to the advantages of its large-scale equipment in mass production.

Reference materials and materials

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[2] Gao, Holmes, Pease. The latest development of micro and ultra-fine grinding technology [A]. The processing of the ⅹ Ⅲ International Mineral Processing Conference (654 volumes 38+0)[C]. Istanbul: Primed Advertising Company, March 37, 2006

Pease1j, Anderson G, Curry D, et al. autogenous and inert grinding using IsaMill [A]. international autogenous grinding and semi-autogenous grinding technology 2006[C]. Vancouver, Canada. 2006(9) Volume 2: 230-244

Wu Jianming. GJ5×2 large double-groove stripper and its application in kaolin stripping [J]. China Powder Technology, 2003,9 (2): 41-43,48.

Ding Hao. Practice of Fine Grinding Coal-series Kaolin by Wet Mixing and Micro-powder Processing Technology [J]. China Nonmetallic Mineral Industry Guide,1999 (3):14-17.

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Xu Xingpei. Deep processing technology and development direction of kaolin [a]. China mineral processing science and technology information network, etc. See: Proceedings of the Seventh National Symposium on Crushing Engineering [c]. 1999.49-55.

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Development and application of GJ 5×2 large double-groove high-strength stirring mill

Wu Jianming, Cao Yongxin

(Beijing Research Institute of Mining and Metallurgy, PC: 100044, Beijing, China)

Abstract: GJ5×2 large-scale high-strength double-tank stirring mill is the latest and largest superfine crushing/layering equipment in China. The stirring mill adopts innovative technologies such as double impeller agitator, square cross-section double-chamber silo and high-pressure air loading start-up. Stirring mill has the characteristics of large output, high superfine grinding efficiency, fine product granularity, continuous production, humanized structure and size, and convenient installation, operation and maintenance. Stirring mill has been applied to the layering of coal-series calcined kaolin in Shanma Products Co., Ltd. The particle size of single-milled -2μm products is 85% -90%, and that of double-milled -2μm products is 94%, and the treatment capacity is1.2-1.5 t/h.

Key words: GJ5×2 large-scale high-strength double-tank stirring mill, ultra-fine crushing/layering, coal-series calcined kaolin.