Gravity separation of history and description of development in China

First, the history of re-election

Gravity separation is based on ore mineral density differential selection methods, beneficiation in contemporary plays an important role. It's a long history, from ancient humans began to understand when the use of metal materials, the use of animal skins in natural metal or panning rivers in natural minerals. Later with a wooden chute for sorting. About 400 years ago the original type of jig , but then the production or workshop-style. 18 to 60 years in the Western industrial revolution took place, the metal of the demand for raw materials increasing l. At the same time the emergence of the steam engine has provided the impetus for the mechanization of production, so the re-election as an industrial sector and the emergence of 1830-1840 was asked in German Haz (Harz) mining the early days of the Pistons continue to be improved jig has been widely used.(Baum jig)。 1892 invented a large-scale wind-driven coal jig with Baum (Baum jig). 1890 United States built the first coal with combat-style shaker ,1896-1898 A · Will Foley (Wilflev) invented the modern type of shaker.Although the shaking was also regarded as a chute, called out of disk, but since then its unique way of sorting and self-contained.With the emergence of shaker, pre-classification sorting, removing mud and other preparatory work is also widely used. Thus, the main process re-election of the type of classification , Sawtooth wave jig  , shaking table and chute already selected in the 19th century, the basic form, and became almost the only way of dressing.

In the 20th century who started the rise of froth flotation,.While in weak magnetic separator made ??after 1890 to obtain promotion.They are dealing with micro-fine disseminated sulphide and magnetite achieved excellent results.． The relative position of re-election has been reduced.But in ore handling capacity still exceeds flotation and magnetic separation. Early 20th century after a period of stagnation, the re-election to continue to deal with coarse-grained method to improve separation efficiency and strengthen the separation direction. 1927 began with heavy media beneficiation method sorting lump, 1936, the United States mascot (Mascot) mining method the first time with a heavy media separation lead-zinc ore.1939 in the Netherlands started using hydrocyclones for concentration and grading, which will refer to the beneficiation process of centrifugal force. 1941 American I. B． B. Humphrey (Iiumphreys) and then made ??into a spiral concentrator, since the re-election exceeded the original vertical flow and slope flow two sorting modes, an increase of static and rotary flow sorting applications. Modern technology laid the basic pattern of re-election

Re-election has the advantage of handling a wide range of ore particle size, sorting it can not do anything other coarse-grained ore beneficiation method. Re-sorting equipment generally simple structure, easy manufacturing, the production does not consume valuable pharmaceutical, and waste tailings discharge less pollution to the environment. After 60 years as people's attention to the ecological balance and the mid-1970s energy crisis, coupled with high-grade ore are declining.Lean ore increased, the advantages of re-election again to be sure, the emergence of new trends. ． Highlighted the performance. In the application of coarse and fine ore pre-sorting on the slime. In recent years, a variety of dynamic dense medium separator and flow membrane processing equipment is a sign of this development.The re-election of the new device is toward large-scale, multi-layered and the application of centrifugal force direction. Re-election of the theory behind the development of production than some. Newton's equations of fluid inertia and resistance to G. G． G.Stokes (Stokes 1851) formula for the study of viscous resistance in the settling velocity of particles in the media foundation. P． P. R． R.Leiting Zhi (Rittinger 1867) the first square of the resistance according to Newton's formula for spherical particles derived settlement beam in the medium-speed formula. R． R. H． H.Richards (Richards 1903) studied the interference settlement and jig beneficiation theoretical issues. A． A. M． M. 。 Gordon (Gaudin 1939) proposed a hierarchy of the jigging motion acceleration theory, and studied the slope flow separation principle. These studies are based on fluid dynamic action proposed.Meyer (Mayer) made ??from the static point of layered potential energy theory, theory of the formation of a layered system and static system dynamic two factions. Theory and practice of re-election order for the system to count the Soviet scholars n. B． B.Leah Shen Ke

(ДЯЩeHKo), in 1940 he published a monograph " gravity separation method . "There are many listed within his own research.This re-selected from the field after starting from the dressing into the body.Department, continue to have a special on the come out.

Re-elect the majority of the early theoretical studies focused on the interpretation of the phenomenon of the process, but trying to use the simple concept expressed in the nature of the process, there are also many different perspectives.The 1950s, they began using modern measurement techniques, including fast photography, radioactive isotopes such as positioning and optical measurement methods for particles and visual description of the media campaign.But in order to resolve these observations to the expression of the so far very little to do.

Today, in addition to other particle sedimentation problem. Most process principle has not yet made ??clear conclusion.Difficult to make quantitative calculations.So in recent years has carried out similar to probability and statistics, and simulation-based research. Through statistical analysis of process variables or understanding the nature of the extension, establish a mathematical model or theoretical experience similar relationship, as calculated level of production, control, or equipment to enlarge the design basis. Gravity separation is also a result from the experience of technology to scientific and mathematical way.

second, the re-election in the country's development

China is the earliest use of metal utensils in the world.In addition to the ancient source of raw material metal part from land-rich deposits, there are a large number come from rivers, coastal sand tin, gold and iron sand deposits . These sands have been enriched in order to carry out washing and smelting.

According to demonstrate, first use of the panning tool is a special wooden tray. Hubei tonglushan Mining unearthed a "boat-shaped wooden bucket" is representative of two thousand years ago panning tool. Song is to use wooden chute. Zhu, or "ping states to talk about" Volume 2 recorded "landing. Lakin pit households only with a large wood, saw profile of, leaving blade marks, cast sand on it, the pan with water and sand to gold book saw pattern in very easily. get. " Up to the Ming and Qing dynasties and development and asked the washing.Qing Yan Ruyu "border provinces Fact Sheet," Volume 9 "sundries" in the records of Nanzheng (Hanzhong) Amoy bed using selected payment situation.Amoy bed made of wood, surrounded by a border. Amoy bed surface by placing a round bamboo basket, the sand poured into the basket, the side of the water, lifting the side of the sand basket toss. Gold from the screen through the bottom slit, the bed fell on Amoy, Amoy bed, placed a wooden groove, further selected gold particles. The sand washing tin, Ming Sung a "Heavenly Creations" in volume 14 had recorded "Where the mountains of tin tin, tin two kinds of water ... .... Tin Heng Wing out of the river water in Guangxi Nandan is a state Hanoi, the quality of the black pieces. Nandan River out of those. Amoy residents ten days ago from south to north, ten days later from north to south Amoy, Amoy take more after their endless sand a hundred years. " Shows the grand year of tin mining and resource rich. Ditto "Heavenly Creations" small iron sand mining also recorded.

China's re-election process to the Qing Dynasty has been considerable development, the formation of a rather extensive cottage.Only under the rule of the feudal system, a rare production technology advances. To the beginning of this century, the Western industrial technology was introduced to China. From the beginning of this century into the shaker f bow and other equipment, and built up areas in Yunnan old mechanized tin concentrator. However, the development of production is still slow.Until the new China was founded. Re-election only to truly large-scale industry developed, the new China was founded in the early stage of China's tungsten, tin production base in Yunnan, Jiangxi and other places to build more than a dozen large and medium gravity concentrator, and a number of processing heavy metals placer election widely put into production. 60 years later, 're-election method is used to promote processing of iron ore, and lead, zinc, antimony and heavy media pre-established non-ferrous metal mining workshop. After 70 years a lot to promote the gold mining ship process to replace the old gold production of artificial selection. Gravity separation is also building materials, chemical industry, especially the coal industry has been widely used.China's re-election technology has now reached a very high level, with the re-election of the production of tungsten, tin concentrate production occupies an important position in the world, the production index, compared with advanced countries, no less. China has also developed its own deal with micro-fine particles of centrifugal concentrator 'machine, oscillating belt chute and other equipment, the composition of the sludge is different from the foreign production process. But with the advanced industrial countries, in technical management, in the consumption of materials and energy consumption _ is still on.There are gaps, further efforts in order to fully reach the world advanced level.