Development history of ore mill

Development trend:
(1) with the development of grinding medium separation system, the size of grinding medium becomes smaller and smaller with the continuous improvement of proct fineness requirements. The separation of small grinding media is one of the most difficult problems in the development of sand mill
it is very difficult to separate small-size media by gap ring (small flow area) and static screen used in traditional sand mill! So more and more use dynamic centrifugal separation system. The centrifugal force proced by the separation rotor driving the medium to rotate makes the medium be thrown around the rotor, and the center of the rotor is mainly slurry. If the separation screen is arranged in the center of the rotor, the material can flow out smoothly through the screen gap, without blockage and wear. Therefore, it is a technological leap in the development history of sand mill to apply the dry air classification principle to the medium separation of sand mill
(2) in the past, several major sand mill manufacturers at home and abroad had a one-sided view; In order to improve the fineness of the proct (rece the particle size), the energy density of the sand mill must be increased! As a result, a lot of pin bar sanding mills with complex structure appeared,
A: the structure-1 of sanding mill is densely arranged with a lot of cemented carbide pin bars on the rotor and stator. The material enters from the upper part and discharges from the bottom after passing through the zigzag "n" line. The wear of medium to pin, rotor and stator is very serious, and the material is often contaminated by metal. And only expensive zirconia grinding medium can be used
b: structure-2 and structure-1 are basically the same, but in order to solve the problem of heat dissipation, a cooling jacket is set on the rotor
C: only the pin bar is arranged on the rotor, while the cooling jacket is arranged on the stator and half rotor. The pin rod is severely worn on the inner surface of the opposite stator, so it is inevitable for the metal to pollute the material
(3) the high energy density outer ring grinding zone of horizontal centrifugal sand mill
after years of misguided and artificially complicated sand mill design, people have finally returned to nature! It is found that the real grinding of materials only occurs in the grinding area with a certain energy density, while the low-energy area only generates heat. In the high energy density region, only the outer ring region with the maximum on-line velocity can appear
A: the sand mill is fed radially from the outer stator, and the material passing through the outer ring grinding area is discharged axially and laterally through the dynamic medium separation screen
b: the grinding material enters the rotor through the side of the hollow shaft and reaches the outer ring grinding area. The drum (stator) of the equipment rotates at different speeds with the inner rotor. The medium separation screen (fixed on the drum) has become a real rotating dynamic separator. The double rotor structure with complex structure requires high coaxial error of each rotating body
C: the grinding material is added from the axial center to the outer ring grinding area, and the ground material is discharged through the outer ring screen ring. The grinding track is the ceramic separation ring. Although the filtration area is increased, the separation ring is seriously worn and easily blocked

Grinding machine is a kind of mining equipment. The utility model has the advantages of convenient operation, convenient pulp self main flow and pulp distribution

In China, the simplest smashing tool, pestle and mortar, appeared more than 2000 BC. The pestle and mortar further evolved into a pedal pestle from 200 to 100 BC. These tools use the lever principle, initially with the rudiment of machinery, but their crushing action is still intermittent
the first continuous crushing machine was the animal mill invented by the public transport team in the fourth century B.C., and the other one was the roller mill, which appeared later than the mill. After 200 A.D., on the basis of pedal type pestle and animal power mill, Du Yu and others of China developed the continuous machine water pestle, continuous two water mill and continuous water rotation mill with hydraulic power as the driving force, which raised the proction efficiency to a new level. These machines are not only used for grain processing, but also for crushing other materials
modern crushing machines were created after steam engines and electric motors were graally improved and popularized. In 1806, the roller crusher driven by steam engine appeared; In 1858, Blake invented the jaw crusher to break rocks; In 1878, the U.S. developed the rotary crusher with continuous crushing action, and its proction efficiency was higher than that of jaw crusher with intermittent crushing action; In 1895, William of the United States invented the impact crusher with low energy consumption
at the same time, grinding machinery also has a corresponding development, the ball mill appeared in the early 19th century; In 1870, on the basis of ball mill, rod mill with uniform discharge particle size was developed; In 1908, the autogenous mill without grinding medium was created. In the 1930s and 1950s, the United States and Germany successively developed vertical shaft medium speed coal mills, such as roller bowl coal mill and roller disc coal mill
the appearance of these crushing machines greatly improves the efficiency of crushing operation. However, e to the different crushing characteristics of various materials, different instries have different requirements on the particle size of procts, so they have created a variety of crushing machines according to different working principles, such as wheel mill, vibration mill, turbine mill, airflow mill, fan mill, sand mill, colloid mill, etc
in the early 1970s, large-scale gyratory crushers with an hourly output of 5000 tons and a maximum feed diameter of 2000 mm, and colloidal mills with a particle size of less than 0.01 μ m have been manufactured

In the middle of the 19th century, some countries in Europe and the United States began to build gravity separation plants. At the end of the 19th century, magnetic separation plants and flotation plants were built. After the 1940s, chemical beneficiation was developed. Since the 1960s, the combined processes of fine gravity separation, fine particle flotation, wet high intensity magnetic separation and beneficiation metallurgy have been developed and built. Since the 1970s, with the continuous development of new technology and new equipment, large-scale concentrators have been built in foreign countries, such as Papua New Guinea concentrator with a daily ore processing capacity of 115000t< In 1909, China designed and built the first gravity concentration plant in Shuikoushan mine, Hunan Province, and then changed it into a flotation plant. By 1949, there were only more than 20 concentrators in China. After 1949, thousands of various types of concentrators (including gravity separation, flotation, magnetic separation and combined process concentrators) were designed and built. The daily ore processing capacity of the third concentrator of Dexing Copper Mine in Jiangxi Province reached 6000t. Since the 1980s, in the crushing and grinding design of concentrators, in order to rece the particle size of crushing procts, save grinding power consumption and realize more crushing and less grinding, Lu 2100mm ultra-fine cone crusher has been adopted in the United States, kh-2200 inertia cone crusher has been adopted in the former Soviet Union, and Lu 2100mm ultra heavy cone crusher has been adopted in the third concentrator of Dexing Copper Mine in Jiangxi, China, The pyhd-900mm rotary disc superfine cone crusher is used in Zaozhuang gold mine of Shandong Province. In order to simplify the process, save steel consumption and rece the cost, the autogenous grinding process is adopted. The nmx4.6m wet autogenous mill is used in the United States, and the Mao wet autogenous mill is used in the first concentrator of Dexing Copper Mine in China. In the design of gravity separation plant, narrow classification, multi-stage grinding and separation, flow membrane separation, especially the application of flow membrane separation, have changed the appearance of fine mud gravity separation. In Britain, 40 layer turning bed and cross flow belt chute are used. In China, centrifugal concentrator, vibrating chute and double-layer belt chute are used. In addition to gravity separation, manual separation and heavy medium separation, laser, radiation and conctance / magnetic separation are developed in the design of preconcentration workshop. In the design of flotation plant, equal floatability, series branch separation, flocculation flotation, carrier flotation and flash flotation are adopted. The flotation equipment includes aeration type and mechanical stirring type, such as "loom" flotation machine in Finland and "100m" flotation column in former Soviet Union. In the design of magnetic separation plant, there are permanent magnetic, electromagnetic, high intensity magnetic and high gradient magnetic separation, especially the application of high intensity magnetic and high gradient magnetic separation, so that weak magnetic minerals can be effectively recovered, and superconcting magnetic separation has opened up a new field of magnetic separation. The comprehensive recovery of associated components is 74 in former Soviet Union and 85-95% in Japan; In China's comprehensive recovery, gold accounts for 25% - 33% of the total output, silver accounts for 65%, and platinum group metals and rare and scattered elements account for almost 100%. In addition, small ore spots are dispersed, mobile concentrator is designed, raw ore is transported by belt for a long distance, concentrate and tailings are transported by pipeline for a long distance and high concentration, and the automation and computer-aided design of beneficiation process are getting more and more effective
with the improvement of process level and the development of equipment, the processing object of concentrator is not only suitable for raw ore, but also for tailings, smelting intermediate procts or slag. The design basis is mainly the design task and relevant documents issued by the superior competent department, and the approved geological exploration report. Mineral processing test report, engineering geological report, topographic map, equipment drawing, etc. organized and approved by competent department. Instrial test reports of new technologies and new equipment shall be subject to the technical appraisal and examination and approval organized by the competent department. Indivial large new equipment used in instrial proction shall be subject to the approval of the competent department. The beneficiation test includes washability test, laboratory test, laboratory expanded continuous test, semi instrial test, instrial test and single test. The scope of application should be listed in Table 1. Table 1 mineral processing test category and scope of application design scale and proct scheme are demonstrated through feasibility study and determined by the competent department in the assigned design task. The design scale is usually expressed by the annual or daily quantity of raw ore, and is divided into large scale, medium scale and small scale according to the national regulations