Yin Xiaodong, Qi Fengyuan, Guo Li, Wang Changhui, Tan Chong, Ma Liang, Yang Zhanhou, Wang Xinjiang
(Xianyang Nonmetallic Mining Research and Design Institute, Xianyang 712021)
Abstract Through the introduction of the principle and application of the CXF series of impact ultrafine powder mills, combined with domestic and international development of related technologies put forward the development goals and trends of the impact ultrafine powder mill.
Keywords Ultrafine powder; impact mill; development direction.
Biography of the first author: Yin Xiaodong, male, born in 1960, president of Xianyang Nonmetallic Mining Research and Design Institute, professor-level senior engineer. Tel: 029-33343053; E-mail: yinxiaodong@sinoma.cn.
I. Overview
To date, ultrafine pulverization methods are mainly mechanical force methods, including airflow mill using high-speed airflow impact; impact ultrafine pulverizer using high-speed mechanical rotary impact and shear effect; friction grinding using Stirring ball mill, vibration ball mill, rotary ball mill, planetary mill; use of shear force colloid mill; use of compressive stress high pressure roller mill; and use of high-pressure jet impact jet pulverizer and so on.
Hamyang Nonmetallic Mining Research and Design Institute, as one of the earliest units to carry out research on ultrafine crushing technology in China, has developed the CXF series of impact ultrafine crushing and grading equipment, which has been recognized by the majority of users by virtue of its lower energy consumption, higher crushing efficiency and product quality and stability. At present, more than 300 units have been sold throughout the country and exported to Africa, widely used in talc, kaolin, calcium carbonate, serpentine, magnesium oxide, barite and other non-metallic minerals, ultrafine crushing [1-5].
Second, the structure principle
CXF51 A-type ultrafine grinding equipment from CM51A-type ultrafine powder mill, QF5A-type turbine classifier, bag dust collector, collector and high-pressure fan and other components.
(A) CM51A ultrafine powder mill
CM51A ultrafine powder mill structure as shown in Figure 1. Less than 8 ~ 10mm of material from the feed hopper through the double screw feeder into the feeding speed of the feed speed according to the actual load of the mill automatically adjusted, and can control the feeding size. Two crushing chamber in-line configuration with each other, the second chamber diameter is slightly larger than a room, separated by the interchangeable circular blocking ring. In the second crushing chamber discharge, also equipped with the same shape of the material ring and fan separated from the same shape. Each crushing chamber is equipped with two rows of rotors. At the top of all rotors, are equipped with high hardness wear-resistant alloy steel made of replaceable hammer head, and its parallel to the opposite is set in the shell on the inside of the specially treated wear-resistant liner, which leaves a small gap. Materials in the crushing chamber with the rotating air movement, the particles of mutual impact, collision, friction, shear; at the same time by the centrifugal force of the rotating body, the particles are crushed by the crushing of the interior wall of the impact, friction, shear and other effects are continuously crushed. Crushing chamber with impact and airflow vibration crushing effect, the most effective crushing interval occurs in each crushing chamber between the two rows of rotors. Material into the first crushing chamber that is crushed into hundreds of micron-sized powder, and the second crushing chamber rotor linear velocity than a room to be larger, after the interval of the powder by the impact of the crushing effect is stronger. Due to the increase in the diameter of the second crushing chamber, this time the powder crushing time is extended, and the crushing chamber rotor also has a grading function, through the fineness of the powder here to a few microns. After the material is crushed by two levels, it is sent to the air classifier by the fan for grading. The coarser particles that do not pass through the classifier are returned to the pulverizer by the rotary unloader for further pulverization. The hard-to-grind gravel and residual impurities in the material can be automatically discharged out of the machine through the machine's ad hoc slagging device. Fine particles through the classifier, into the micro-powder collection system and become the final product.
Figure 1 CM type ultrafine powder mill structure diagram
1-machine base; 2-slag discharging device; 3-main shaft; 4-air inlet; 5-feeder; 6- hopper; 7-one chamber rotor; 8-one chamber retaining ring; 9-liner; 10-two chamber rotor; 11-two chamber retaining ring; 12-fan
(ii) QF5 Type QF5 turbine classifier (Figure 2-)
The QF5 turbine classifier relies on the inertial centrifugal force generated by the rotor and the force of the airflow on the particles to separate coarse and fine particles to achieve the purpose of grading. Its working principle is: from the pulverizer or material dispersing equipment containing solid-phase mass airflow through the feed pipe 1 into the classifier, and from the secondary air inlet 6 into the airflow mixing to the rotor area, as shown in Figure 2. The rotor with blades rotates at a certain speed to make the airflow in the area do rotary motion, forming a centrifugal force field, thus separating the coarse and fine materials. The coarse particles are discharged through the return pipe 7. And fine particles through the gap between the rotor blades, by the airflow out of the classifier and become graded products. The cross section of the classifier rotor is shown in Figure 3. The rotor is equipped with a number of blades, radially with a certain forward inclination angle, the upper and lower leaf discs have different diameters.The rotational speed of the QF5 turbo classifier is adjustable, which can be selected according to the requirements of different materials and the fineness of the products.
Figure 2 Working principle diagram of QF type turbo classifier
1-Inlet pipe; 2-Rotor; 3-Shell; 4-Drive parts; 5-Outlet pipe; 6-Secondary air pipe; 7-Return pipe. -secondary air pipe; 7-return pipe
Figure 3 Cross-section of the rotor
(C) Process flow
The process flow of CXF type impact ultrafine pulverizing system is shown in Fig. 4.It consists of CM type ultrafine grinding mill, QF type turbine classifier, microparticle powder collector, tail blower, and electric control cabinet. . Material (≤ 10mm) from the hopper through the double screw feeder into the ultra-fine mill 1, feed speed based on the actual load of the mill automatically adjusted, and control the feed size. The material in the mill, by high-speed rotating hammer impact, grinding, shearing and collision between materials to achieve crushing. Crushed material with the airflow into the turbine classifier 2, according to the required particle size to adjust the classifier grading point, after grading the ultra-fine powder into the collector 3 collection, coarse particles through the exit 5 to return to the mill regrind (closed-circuit system), or as a product of the 2 collection (open-circuit system), the tail wind into the dust collector purified by the blower discharge. The total weight of the whole system equipment is about 14 t, the total installed capacity is 92 kW, the total area is nearly 90 m2 (15 m×6 m), the maximum installation height is about 8.0 m. The whole system works under negative pressure without dust hazard.
Figure 4 CXF type impact ultrafine grinding system process flow
Three, application
CM51 type impact ultrafine grinding mill and QF5 type turbo classifier is Xianyang Nonmetallic Mining Research and Design Institute in undertaking the national science and technology research project based on the success of the research in 1993, to fill the gaps in the country. After several years of continuous improvement and updating, its performance indicators in some aspects has exceeded the level of foreign imported equipment, has been stereotyped as CM51A ultra-fine pulverizer and QF5A air classifier, widely used in a variety of functional non-metallic mineral materials and other materials in the production of ultra-fine powder. Some of the applications of ultrafine pulverization are introduced below.
(I) Coal-based kaolin minerals ultrafine powder application
China's coal-based kaolin ultrafine products are divided into calcined and non-calcined soil according to the whiteness; according to the particle size is divided into filler-grade (-10 μm) products and coating-grade (-2 μm) products. Among them, the processing of filler-grade coal-based calcined kaolin products, many domestic information on the public promotion of the production process and equipment are usually: raw ore - coarse crushing - ultra-fine crushing, grading (Hanyang Mill) - calcination - depolymerization, breaking - product packaging. Among them, Xianyang Mill refers to the CM51A ultrafine mill and QF5A air classifier produced by the Powder Center of Xianyang Nonmetallic Mining Research and Design Institute, which is the raw ore less than 10mm by the CM51A ultrafine mill ultrafine crushing and QF5A air classifier classification, that is, the calcined raw material with a passage rate of -10μm ≥ 90%. The technology and equipment are now widely used in the coal and non-coal kaolin ultrafine deep processing products in Wuhai, Inner Mongolia, Shizuishan, Ningxia, Datong, Shanxi and other places. Some of the areas of production practice results are shown in Table 1.
Table 1 part of the coal kaolin ultrafine crushing practice
(B) Calcite minerals ultrafine crushing applications
Hamyang Nonmetallic Mining Research and Design Institute of its own development and production of the CXF series of impact ultrafine grinding mill for calcite carbonate minerals of ultrafine crushing, mainly used for the production of 800 ~ 1500 mesh ultrafine heavy carbonate, mainly used in the production of the material, the production of the material, and the production of the material. 1500 mesh ultrafine heavy calcium carbonate, its products are now widely used in plastics, rubber, papermaking filler and other fields. Some of the production practices in some areas, the results are shown in Table 2.
Table 2 Part of the practice of ultrafine crushing of calcium carbonate
Note: The results of the product particle size test, are provided by the manufacturer.
(C) Application of ultrafine crushing of wollastonite
CXF51A impact type ultrafine crushing and grading complete set of equipment for wollastonite processing, the output can reach 166.8 kg/h, the product particle size (10μm throughput) reaches 100%, d50 = 2.66μm, and it can keep wollastonite micro-powder with a high aspect ratio.
(D) the application of ultrafine crushing of other mineral materials
CM5 lA type ultrafine crusher and QF5A type air classifier composed of ultrafine crushing process, ultrafine crushing of a variety of other minerals studied, are also achieved good results, involving materials such as: talc, crystalline graphite, semi-soft kaolin, illite, crushed mica, barite, magnesite, Zeolite, chlorite, tremolite, muscovite, sericite, iron oxide red, coal, natural asphalt, p-phenylenediamine, etc., of which some of the materials applied to the production of practical results are shown in Table 3.
Table 3 Some of the materials applied to the application of ultra-fine crushing of the production of practical
(E) CM51A type of ultra-fine crushing equipment can be avoided to avoid crushing the process of pollution of the product
Using the CM51A type of ultra-fine crushing equipment by the CM51A type ultrafine crusher process, the output of a place in Shandong 50 t of secondary talc for ultrafine pulverization test production, in the original ore Fe content of 1.37%, after ultrafine pulverization, -10 μm throughput rate of 85.5% of the product in the Fe content of 1.27%, slag in the Fe content of 1.43%, indicating that part of the original ore iron through the crusher ad hoc slagging device discharge The purity of talc has been improved after ultrafine pulverization. For the ultrafine crushing of high purity graphite, such as a factory in Inner Mongolia, high carbon graphite, specifications for the LG100-96. 96.28% carbon grade, 3.08% ash, volatile matter 1.14%, moisture 0.57%. In different classifier speed conditions of ultrafine crushed product testing can be seen: products - 500 mesh through rate of 97.93% to 99.90%, Fe content are ≤ 100 × 10-6, carbon grade 96.88% to 97.68%, ash 1.67% to 2.05%, volatile matter 0.65% to 1.16%, moisture 0.3% to 0.6%. The results of this pilot study fully meet the requirements of foreign investors, the product is now exported in bulk to Japan, South Korea, Switzerland and other countries. It can be seen that the high carbon graphite after CM51A type ultrafine pulverizer crushed, the purity of the product did not change significantly, only the fineness has become finer.
(F) CM51A type ultrafine pulverizing equipment can be used for material breaking
CM51A type ultrafine pulverizing mill also has the function of depolymerization and breaking up. For light calcium carbonate, due to the chemical production of light calcium carbonate, the production process is often part of the conditions change, resulting in products such as carbonization is incomplete, part of the particles are too large, and some of the ultrafine particles agglomeration, resulting in the phenomenon of unstable final product; and for calcined kaolin, the product after calcination, the formation of agglomeration phenomenon, affecting the effect of its use. By improving the working condition parameters of CM51A ultrafine mill, the instability of light calcium products and the agglomeration phenomenon of calcined kaolin ultrafine powder have been completely solved. Has been successfully applied to a light calcium carbonate enterprises in Shanghai and the domestic calcined kaolin deagglomeration and breaking up.
Four, the development trend
(a) the optimization of equipment technical parameters
In order to meet the non-metallic minerals market on the growing demand for crushing equipment, to fully tap the potential of the CXF51 A-impact ultrafine crushing and grading equipment, in the analysis of the technical performance of the equipment on the basis of technological modification, through the crushing force, rotor linear speed, feeding By analyzing the crushing force, rotor linear velocity, feed size, the role of the fan inside the CM51 ultra-fine pulverizer and other comprehensive analysis and research, and combined with our research on the wear-resistant materials that should be used in the impact-type ultra-fine pulverizer, we have determined the technical transformation program, and successfully transformed the CXF51 A-type impact-type ultra-fine pulverizing and grading equipment into CXF51 C-type impact-type ultra-fine pulverizing and grading equipment. Kaolin as raw material for industrial testing, achieved more satisfactory results.
Through technological transformation, CM51A type impact ultrafine crusher rotor linear speed on the basis of the original increased by 8% to 12%, the feed size increased to 0 ~ 15mm, and the system air volume to make appropriate adjustments, the output was eventually increased by 20% to 30%, the product particle size of d97 reduced to 2.03μm, the product particles in the shape of the removal of the angular and leveling of the disintegration surface, shape Comparison of uniformity, in the subsequent application, so that the surface modification effect is good, significantly reduce the amount of modifier, and to avoid these parts in the microscopic are composite materials within the stress concentration points, and the use of non-metallic minerals filler effect of the adverse effects of the use of the powder to improve the ultrafine coal kaolin powder in the use of the application effect.
The remodeled CXF51 C-type equipment has been sold more than 20 sets, users reflect good.
(2) product serialization
In fully exploiting the potential of the existing equipment at the same time, we also pay attention to the serialization of new product development, in the 51-type equipment on the basis of the success of experience, we have successfully developed the CXF61-type impact ultrafine powder grading complete sets of equipment by undertaking the national scientific research institutes and technological research and development of special funds for projects in the main performance indicators remain unchanged, under the condition of single machine output than the CXF51-type equipment, the CXF51-type equipment is more efficient than the CXF51-type equipment. In the case of the main performance indicators of the product remain unchanged, the output of a single machine than the CXF51 type doubled to 0.4-0.6 t / h, won the second prize of the China National Materials Group Corporation for scientific and technological progress, the equipment has completed the finalization of the product, put into mass production, and will enter the market immediately.
(C) the further development of new equipment
With the progress of science and technology, non-metallic mineral materials are increasingly wide range of applications, as one of the important means of deep processing of non-metallic minerals, ultra-fine crushing technology has also made great progress. At present, the development trend of ultrafine crushing equipment is large-scale, automation, energy saving. Foreign large-scale dry ultrafine crushing equipment in recent years in large-scale, energy-saving has made great progress, the output of a single machine has been able to reach 4 ~ 5 t / h, energy consumption per unit of product ≤ 120 (kW - h) / t, the equipment has a high level of automation, the adjustment of the parameters is very convenient.
Hamyang Nonmetallic Mining Research and Design Institute is also in this area of research and development work, based on the original research combined with the study of foreign advanced technology and equipment, the impact type ultra-fine pulverizer and the working principle of the air mill for a reasonable integration and innovation, resulting in the formation of a new type of ultra-fine pulverizer collision. Compared with the impact type ultrafine mill, the collision type ultrafine mill absorbed the characteristics of the air mill, the material in the crushing chamber of the impact is more violent, more frequent, improve the efficiency of the crushing; compared with the simple air mill, due to the integration of the impact type of the characteristics of the mill, so the material into the material particle size is greatly increased, a crushing ratio of a very large, crushing the utilization of energy is significantly improved. Impact type ultrafine pulverizer single machine output can be greatly improved, the product 1250 mesh, 90% throughput, capacity> 1.5 t / h. The design of the equipment is currently underway.
V. Prospects
Impact ultra-fine crushing as an important component of ultra-fine crushing form, due to a simple process, equipment performance and stability, the product is easy to pack and transport, good environmental performance and other advantages, has a good development prospects.
References
[1] Wang Xinjiang, Qi Fengyuan, Wu Zhilin. Impact ultrafine mill on calcite minerals of ultrafine crushing practice and process technology research [J]. Nonmetallic Mining, 2000(3)
[2] WANG Changhui, TAN Yong, MA Liang. Analysis of the influence of rotor structure parameters of microfine classifier on classification point［J］. China Powder Technology, 2006(3)
[3] Zhu Yingbo, Gong Guohua. A kind of ultrafine crushing equipment with dual functions of crushing and purification［J］. Nonmetallic Mining, 2003(4)
[4] Wang Xinjiang. Processing and utilization of functional nonmetallic mineral materials by impact ultrafine pulverizer［J］. China nonmetallic mineral industry guide, 2003 (4)
[5] Ma Liang, Qi Fengyuan, Tan Yong. CXF51A type impact ultrafine powder mill technology and application [J]. Nonmetallic Mining, 2005(4)
Application and Development of Impact Ultrafine Mill
Yin Xiaodong, Qi Fengyuan, Guo Li, Wang Zhanghui, Tan Yong, Ma Liang. Yang Zhanhou, Wang Xinjiang
(Xian Yang Research ＆ Design Institute Of Non-Metallic Minerals, Xian Yang 712021)
Abstract: Through analyzing the working principle and application of the mill, we have developed a new methodology to analyze the impact of the mill. analysing the working principle and application condition of CXF series impact ultrafine mill, integrating the development of relative technology at home and abroad, the article put forward the development objective and trend of the impact ultrafine mill.
Key words：ultrafine-powder，impact
Key words: ultrafine-powder, impact mill, development direction.