Study of high selective grinding mechanism of tungsten
|School||Jiangxi University of Technology|
|Course||Mineral Processing Engineering|
|Keywords||tungsten ore compressive strength of irregular ore block compressive strength ofstandard test specimen ball grinding mill|
Tungsten is a kind of important and rare metals, known as a "teeth" of industry, used in various fields. But with the mass exploiting of tungsten, the tungsten resources approach to scarcity, and wolfrmite with the high grade and easy to choose have become less and less. Nowadays, most of the exploiting tungsten is mainly associated with multi-metal in China, with the characteristics of poor, fine-grain, miscellaneous and difficult to choose. Especially the fine disseminated extent of tungsten, it needs to be crushed to a certain fineness to monomer separation, therefore, it will be bound to increase its over crushing, and then mill conditions become more serious.Nowadays, the trends of mining are energy conservation and emissions reduction, and resource comprehensive recycling, therefore it will embark from the tungsten high selectivity in this thesis. Paper mainly takes two points as high efficiency and selectivity:the essence of efficiency is decreasing consumption, lower energy consumption, and reducing equipment wear and tear; The selectivity is to increase the monomer separation degree of tungsten, it can fully monomer separated at the befitting grain, to avoid over crushing of tungsten ore and improve the recovery of tungsten. So it will embark from the grinding to research and solve these problems in this thesis.The Mechanical properties of ore, especially compressive strength, are very important for crushing and grinding. Therefore, the accuracy of compressive strength for ore crushing and grinding is a very important parameter, but traditional compressive strength that is obtained by measuring compressive strength of the standard specimens is larger, so we study of compressive strength of irregular ore block and verify its accuracy. We mainly research the grinding of tungsten ore from the following several aspects:(1) Through the laboratory grinding experiment, we can study the effects of grinding conditions (grinding concentration, the ball filling rate and the grinding media) for over crushing in the grinding process. Test found that the appropriate grinding concentration and ball filling rate can improve the fineness of the ore,while reducing the over-crushed. Through the contrast test of steel balls and steel forgings with same weight, we can find that the steel forging can reduce the over-crushed production rate of tungsten by1.26%lower than the steel ball grinding. Above of all, the test results showed that pre-qualified grain fractions elect to reduce tungsten ore crushed.(2) Through the "design export" of orthogonal design software, simulated design of grinding conditions of tungsten ore was conducted, the production of the-74μm and-10μm as a response output. We can get the best grinding condition after the test. Eventually, the grinding concentration and the grinding time is the main influence factor, and given the optimal solution is provided that grinding concentration range is:60%～63.86%, steel ball filling rate range is:40～45%, and grinding time is:4～4.24min. (3) Select two different kinds of tungsten, and make a comparison about compressive strength of standard specimen and irregular ore block, compared with the standard specimen of invariable compressive strength, compressive strength of irregular ore increasing with the reduction in the quality of nuggets, but the compressive strength of the standard specimens is irregular specimens’several times.(4) It is comparison that compressive strength of standard test specimen and irregular ore block in grinding process by the laboratory accuracy tests. Firstly, we have established polynomial of compressive strength-particle size in irregular ore block; secondly, getting compressive strength according to the granularity of raw ore, calculating both the compressive strength of steel ball, and taking grinding compared, the test results show that the compressive strength of irregular ore blocks is more accurate, a finer granularity of grinding and over crushing is lighter, and monomer separation degree of effect is good.(5) The success of the laboratory test provides the basis for the application of industrial production. These results apply to industrial production, and finally the result is that the effect of80mm steel ball is better than the original100mm steel ball, over grinding reducing by3.06%, loss rate of tungsten ore reducing by4.45%. Meanwhile, consumption of steel ball and power consumption are decreased, and the grinding capacity has increased, which fully shows the accuracy of the compressive strength of the irregular ore block.