Ball Mill Energy-saving New Ways Of Mechanism And Applied Research

The mineral resource is material base of the national economy construction and the social development. The present stage, in our country,95% above energy, 80% above industrial raw material,70% above agricultural production originates from the mineral resource,30% above agricultural water and the tap water stems from the ground water which belong to the category of mineral resource. It can be said that there is not the revising stable supply of the mineral resource, there is also not the healthy development of the modern economy and society. However, the mineral resource's development use need consume great energy. The energy consumption, mining,mineral processing and smelting of metalliferous ore, reaches as high as above 15% of the national total energy consumption. The mine energy consumption accounts for about 35-50%, the metallurgy energy consumption is about 50-65%, in the mining and processing enterprise, mining consumes energy 1/3, the mineral processing consumes energy 2/3, and in the mineral processing plant, the grinding energy consumption, occupies 50% of the entire factory's, is 1/3 of the mining and processing enterprise's. Therefore, in process of mineral resource's development use, specially crushing and grinding will be facing the arduous task of saving energy and reducing consumption. The ball mill also explained from the birth to the industrial application more than 100 years history, in mineral grinding of the giant tonnage and the low-priced, at present and in the next quite long time, the ball mill also will be one kind of unreplaceable important grinding equipment. So studying new ball grinding technology reduces grinding energy consumption of the ball mill, this have the practical significance to realize "the energy development and saving".The grinding course is a function transformation. In the course, the input's power of grinding machine transforms largely the grinding loss merit, and very few for the useful energy. The steel ball has randomness to crush ore grain, grinding process of ball mill is a stochastic process, crushing probability is low, and the broken ore process loses the big energy. Thus it can be seen, the primary cause of high energy consumption of the ball mill is big the losing merit and low the crushing probability, saving energy should pay attention to two aspects, which how to enhance crushing probability of the mineral and raise crushing efficiency of the medium. Therefore, the paper, revolves two goals that enhance utilization ratio of the medium energy and crushing probability of the mineral, expounds coarse mill and fine mill to realize mechanism of saving energy and reducing consumption by three aspects that use the new grinding technology make ball medium accuracy,ball-load-addition science,suitable medium shape.The feeding size range of coarse grinding is wide, broken ratio is big. It need add many kinds of steel balls, thus in the coarse grinding process not only it need choose precisely steel ball size to guarantee precise steel ball size of various grades in the coarse grinding process, but also to guarantee the scientific allocated proportion of various ball diameter. Therefore, in view of characteristic of coarse grinding craft and the medium request, the new grinding technology of accurate ball-load-addition method was adopted in the coarse grinding section. The research content of accurate ball load-addition method have three aspects:(1) single ball diameter is precise; (2) overall ball is precise;(3) ball addition is precise. In the grinding process, the comminution probability of ore grain is decided the probability of the steel ball bumping into ore grain (collision probability) and after happening comminution (comminution probability), collision probability is higher, comminution probability is only then higher. But only the steel ball carries enough energy, the ore grain is comminuted. Only in the situation of precise ball diameter and science ball-load-addition, comminution probability is biggest, the stave loss's energy reduce, the energy utilization ration of steel ball enhance, the medium consumption also drops, because the medium consumption and the energy consumption are proportional nearly.The grinding course is a function transformation, is also an energy transfer process. The energy which steel ball carries, besides transforms into the ore's deformation energy, crack forming and expansion energy and the newborn surface energy, but because between the material, the grinding medium friction, the vibration was consumed. Therefore, The energy E which steel ball carries was divided into two parts:to the ore block acting W有, the energy which loses by other formsW损,E=W有+W损,when input energy E is invariable,W损reduces,W有will increases, then the energy utilization ration of steel ballη=W有/E×100% is enhanced, the medium consumption will also reduce.W有is decided comminution probability of steel ball bumping into ore grain. To a group ore grain of certain granularity, the collision probability of steel ball bumping into ore grain is decided by attacking times and the surface area of steel ball. Duringηenhancement, the grinding effect should be paid close attention(the energy uses effectively), if the energy that the steel ball transmits ore grain make ore grain break not to need, form nonessential stave or invalid stave, but needs to break ore grain actually not stave, creates the coarse grade and the thin grade excessively are many in the grinding product, not only the energy has be wasted, and the degree of dissociation are not high, the grinding goal and duty were violated. So During enhancing energy utilization ration of media and reducing energy consumption in grinding process, the grinding effect should be paid close attention, realizes maximization of ore grain comminution energy and effective comminution energy, also namely realizes the medium energy transfer maximization and the validity.The energy of the steel ball transfer ore grain make the ore grain to occur comminution, may choose the appropriate inferable formula of comminution power loss theory to calculate, The computed result indicated:In loading certain situation, the ball diameter was bigger, the number was less, steel ball, attacked ore grain number of times less, the attrition area was also small, hitted ore grain created easily the excessive comminution, not hitted the coarse grade were many, the product characteristic was not good, comminution efficiency was not high, energy utilization ration was not high. On the contrary, the ball diameter was smaller, the number was more, steel ball attacked less ore grain number of times more, the attrition area was also bigger, but the effective comminution energy use of ore grain was not also high, because any ore comminution need achieve certain energy density. Only when ball diameter was precise and ball allocated proportion was science, comminution energy of ore grain effective comminution energy would had realized maximization, the grinding product quality was improved, and the grinding energy consumption was reduced. From energy utilization ration of steel ball, precise ball diameter was higher than 28% of oversized ball diameter's, accurate ball-load-addition plan was higher than 9.15% of the present factory's. The comminution power loss of mineral and the grinding effect showed:the event quantity of ore grain comminution not only considered maximization of energy transfer, but also had considered the mineral comminution validity in the energy transfer process. Therefore, in grinding process we not only may use the event quantity of ore grain comminution to judge grinding effect quality, but may also to judge the grinding method whether to have the effect of saving energy and reducing consumption. After ball diameter adjusted precise from oversized,impacting strength reduced, the attrition speed of steel ball reduced, the consumption quantity decreased, After ball diameter precise, the biggest diameter reduced in mills, the glide of steel ball weakened, the power of overcoming the glide reduced, the grinding machine consumed the absolute power to drop finally, namely absolute electric quantity dropped. The dual function of relative drop and absolute drop realized saving energy and reducing consumption of ball mill.In view of special craft characteristic of the fine grinding work, the fine grinding work adopted the iron section to substitute tradition steel ball. The fine grinding work replaced the steel ball with the iron section, to be able to realize the energy transfer maximization and the validity, not only he quality of grinding product could be enhanced, but also the medium consumption could be reduced. Because the iron section is easy to revolve its axial rotation, moreover as a result of its shape's particularity, rotation is difficult in the mill, glide between the medium is weakened. Therefore, after fine grinding work replaced steel ball with the iron section, in mill the medium glide was weakened, this phenomenon was more remarkable than the small steel ball's, the absolute power of the mill dropped, the absolute electric quantity obviously dropped, then the remarkable saving energy effect of fine mill was realized. The productivity enhancement caused the relative drop of medium consume, the impulse reduced, then caused the machinery attrition to reduce, the absolute consumption failed down. The dual function of relative drop and absolute drop caused remarkable drop of medium consumption. The new grinding technology has carried on the industrial test and the application in Yunnan Tin company,Yunnan copper company,Jinchuan Corporation and Mengze Mining and metallurgy Company and so on more than 10 mine companies, this company have obtained the remarkable the effect of saving energy and reducing consumption, and has had the remarkable economic efficiency. the new grinding technology obtained the remarkable effect of saving energy and reducing consumption in the application of different ore type (Tin copper paragenetic mineral, sulphur-nickel ore, lead-zinc mine, copper mine) and different grinding flow (a section grinding flow, standard two section grinding flow, non-standard two section grinding flow), the electricity consumes dropped 20～40%, the medium consumption dropped 10～30%. It had proven universality, maturation and reliability of the new grinding technology in application of saving energy and reducing consumption of mineral processing plant. If 60% mine enterprise of the national, according to reckoning the electricity consumes will save above 4,000,000,000 kWh every year, the steel ball consumption will savel35,000 tons every year. It explained the new grinding technology is worth vigorously promoting and the application new technology, and opened the new way for saving energy and reducing consumption of mineral processing plant.