how to improve the working efficiency of ball mill?
Added water amount, grinding ball, raw material, electric current, dispersing agent, reduction gear influence the working efficiency of ball mill greatly. So we shall improve the efficiency of ball mill from these factors.
1. Added Water Amount. The water content of the grinding material will influence the working efficiency greatly. So adding enough water onto the grinding stone can improve the working efficiency.
2. Grinding Ball. Generally speaking, grinding ball with various diameters is good for stone and ore grinding, for it can fully grinding different size of stone ore.
3. Raw material of ball mill. The raw material which can increase the weight of the ball mill will also increase the inertia of Ball mill which will also improve the efficiency.
4. Electric current. The flow amount of electric current is the energy of ball mill. If the flow amount of current increase, the efficiency will also be improved. However, we cannot increase the flow of it at random, for there is an upper limit to make sure the power of ball mill within the rated power scope. Otherwise, the ball mill will be burned up.
5. Reduction gear. The rotation speed influences the working efficiency greatly and strictly. The quicker the rotation speed is, the higher the working efficiency is. So install the speed adjustment device can suitably change the rotating speed of ball mill and improve the working efficiency to some extent. Install a transducer can also reach this goal.
ten ways to improve the grinding efficiency of your ball mill
There are a lot of problems that most mineral processing plant meet when operating theball mill, such as low grinding efficiency, low processing capacity, high energy consumption, unstable product fineness of the ball mill. So how to effectively improve the grinding efficiency of ball mill is an important issue for the mineral processing plants. Here are ten ways to improve the grinding efficiency of ball mill.
The complexity of grindability is determined by ore hardness, toughness, dissociation and structural defects. Small grindability, the ore is easier to grind, the wear of lining plate and steel ball is lower, and the energy consumption is also lower.Therefore, the property of raw ore directly affects the productivity of the ball mill.
The larger feed size, the more work that the ball mill needs to do on the ore. To achieve the specified grinding fineness, the workload of ball mill will be increased inevitably, and then, the energy consumption and power consumption will be increased accordingly.
In order to reduce the feed size of ore, the particle size of crushing product must be small, that is, "morecrushingand less grinding". Moreover,the efficiency of crushing is obviously higher than that of grinding, and the energy consumption of crushing is low, which is about 12%~25% of the grinding.
In the case of a certain milling speed, larger filling rate, bigger grinding area, and stronger grinding effect. However, the power consumption is also large, and it is easy to change the motion state of the steel ball if the filling rate is too high, then the impact effect on large particle materials is reduced. Conversely,the smaller filling rate, the weaker grinding effect.
For many mineral processing plants, the filling rate is generally at 45%~50%. But the condition of mineral processing plants is different, just copying othersfilling rate cannot obtain the ideal grinding effect. The specific value should be decided by the mineral processing test.
Since the contact between steel ball in the ball mill and ore is point-to-point. If the diameter of steel ball is too large, the crushing force is also large, so the ore is crushed along the direction of the penetrating force, not the interface among different minerals. This crushing is not an option, which doesnt meet the purpose of grinding.
In addition, in the case of the same filling rate, too large diameter of the steel ball results in less steel balls, low crushing probability, serious over-crushing phenomenon and uneven product particle size. But if the steel ball is too small, the crushing force on the ore is small, and the grinding efficiency is low according. Therefore, it is very important for grinding efficiency to adopting accurate size of the steel ball and its proportion.
Obviously,the grinding action between steel ball and ore causes the wear of steel balls, which can change the proportion of steel balls, affect the grinding process and cause the fineness change of grinding products. Therefore, only by adopting reasonable steel ball supplementation system can the ball mill keep stable operation.
Low grinding density, fast pulp flow,the material is not easy to stick around the steel ball,so the impact and grinding effect of steel ball on materials is weak,theparticle size of ore discharging is unqualified, and the ideal grinding efficiency cannot be achieved;
High grinding density, the material is easy to stick around the steel ball, so the impact and grinding effect of steel ball on materials is good, but the pulp flows slow, which is not conducive to improve the processing capacity of the ball mill.
There are some measures taken to control the grinding density. For example, control the ore feed of the ball mill, control the water supply of the ball mill, adjust the classifying effect, and control the particle size composition and moisture of the sand return.
In actual production, the grinding process can be optimized according to the ore properties, such asthe disseminatedgrain size ofuseful minerals, monomer dissociation degree, the disseminated grain size of gangue minerals. For example, adopting pre-discarding tailings, pre-enrichment, stage grinding, pre-classification to optimize the grinding process, which not only reduces the amount of grinding, but also recovers the useful minerals as soon as possible.
Classifying efficiency plays an important role in grinding efficiency. High classifying efficiency means that those qualified grains can be discharged timely and efficiently,while low classifying efficiency means that most qualified grains are not discharged and sent to the ball mill for re-grinding, which is easy to cause over-grinding and thus affecting the separating effect.
Sand-returning ratio is the ratio between the amount of sand return of ball mill and the feeding capacity of raw ore, which can directly affect the productivity of the ball mill. One way to improve the sand-returning ratio is to increase the feeding capacity of raw ore, another way is to reduce the shaft height of the spiral classifier.
But there is also a limited value in the improvement of sand-returning ratio. When it is increased to a certain value, the increase amplitude of the productivity is very small,the total feeding capacity of the ball mill is very close to the maximum processing capacity of the ball mill, that may cause overage grind, so the sand-returning ratio should not be too large.
There are many variable parameters during the grinding operation, and one change will inevitably lead to the change of many factors one after another. Generally, the manual operation control may cause unstable production, while the automatic control can keep the grinding and classifying in a stable and suitable state, thus improving the grinding efficiency.
There are many factors affect the grinding efficiency in the grinding process. Many factors can be judged as qualitative analysis, which are difficult to make quantitative analysis. therefore, the ball mill operator must do a comprehensive analysis according to the actual production situation and the result of the qualitative analysis,thus drawing the reasonable parameters to decrease the production cost, saving energy and reduce the consumption.
how to improve working efficiency of ball mill
The particle size of the material entering the ball mill is controlled between 25-15 mm (the diameter of the ball mill is different for different feed sizes).Excessive rules will cause the ball mill to have too much fine material during the grinding process and cannot achieve the friction between the material and the material.Too thick will cause the steel ball to break the material for a long time, and will also increase the wear of the steel ball and the liner, and increase the maintenance cost of the mill.
The feeding method of the ball mill is also very important to achieve uniform feeding.If the feeding is too small, there will be no material layer in the ball mill, and the steel ball will hit the steel ball and the steel ball will rub the steel ball, which will also cause waste of power resources.If too much feeding will cause the ball mill to rise, the rising belly will reduce the efficiency of the steel ball inside the ball mill, and the qualified materials can not be discharged, reducing the output.Therefore, it should be uniformly fed during the feeding process.
Increasing the effective volume of the ball mill can increase the efficiency of the mill production.Ordinary alloy linings are thick and heavy, which reduces the effective volume of the mill and increases the power consumption, which reduces the production efficiency of the ball mill.Therefore, the material of the lining is very important. ZGMn13 (high manganese steel) lining is a suitable choice. The lining is reasonable in thickness and wearable. The surface hardness can reach HV500, which is equivalent to about HRC45.This can increase the wear resistance of the liner and increase the effective volume of the cylinder, thereby improving the working efficiency of the ball mill.
The processing capacity of the ball mill increases with the increase of the filling rate of the steel ball. Increasing the filling rate increases the probability of the ball grinding the ore and the self-grinding effect of the ore.The filling rate of the wet type lattice ball mill is generally 40-50%, the filling rate of the overflow type ball mill is generally 35-40%, and the filling rate of the dry type lattice type ball mill is generally 25-35%.
The speed of the mill will produce three ways of moving the ball:
According to the different grinding conditions, the proportion of the diameter of the steel ball is different. The diameter of the steel ball is generally divided into 120, 100, 80, 60, 40mm, etc. If there are many large materials inside the mill, then the choice is made. The proportion of the large diameter of the steel ball should be more. If there are many small pieces of material inside the mill, the smaller diameter should be more when selecting the steel ball.Because large diameter steel balls are mainly broken, small diameter steel balls are mainly used to grind materials.
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three ways to effectively increase the output of cement ball mill - hxjq
2. Improve the grinding system of cement ball mill to increase the grinding efficiency. The improvement of the grinding efficiency makes the finished product to be selected maximally and timely, thus reducing the rate of the powder back to the machine. As a result, the load of cement ball mill has been reduced accordingly. The body transformation, that is, grinding system improvement, is the most fundamental solution.
3. Add high efficiency separator. After adding crusher and high efficiency separator, the particle size of the materials to be ground is reduced, so does the powder selection efficiency. Low efficiency of grinding system will not only affect the output of cement ball mill, but also affect the quality of cement.
how to improve ball mill performance
Application of value engineering techniques to grinding process modelling led to the identification of two basic functions of the ball mill-classifier circuit. In terms of a specified circuit product size which is used to differentiate between coarse or oversize material and fines or undersize material, these basic functions are (a) breakage of the coarse material and (b) removal of the fines. It was proposed that it may be useful to relate circuit design and operating variables to these basic circuit functions, which although related, are conceptually quite distinguishable. If each could be quantified by a suitable parameter, then either or the two together may be correlated to overall circuit efficiency, and hence used to link individual design and operating variables to overall circuit performance.
Major design and operating variables in closed circuit ball milling of a specified feed to a desired product size are summarized in Table 1. The purpose of process modelling is to establish cause and effect relationships between physical design and operating variables and the performance objectives of the circuit. Subsequently, output and efficiency can be maximized. The fundamental issue addressed by ball mill circuit modelling is thus depicted in Figure 1 (McIvor, 1989).
In the simplest form of plant experimentation, a key performance parameter (such as the fineness of the final product) is measured with and without a specific change to the circuit. Within the constraints imposed by the accuracy of measurements and assumptions about the constancy of other inputs (including the ore characteristics), the relative values of this parameter are used to evaluate the effect of the change on circuit performance.
Bond work index analysis takes this method of experimentation several steps further. During comparative testwork, variations in the ore grindability, grinding energy input, and feed and product sizing are measured and accounted for through the grinding circuit model embodied in the work index formulation. For each set of data, both the circuit operating work index and the laboratory test work index of the circuit feed are determined. Relative work index efficiencies with and without the change to the circuit can then be calculated and compared.
Consider a ball mill circuit processing material of a given feed size and at a given throughput rate to a target product size, the latter which once again distinguishes the fines from the coarse material. The production rate of fines or new product size material can be calculated from the circuit feed and product size distributions and the throughput rate of the circuit. Based on the energy expended in the ball mill, the production rate of new product size material (tonnes/h) equals the amount produced per unit of energy applied (tonnes/kwh) times the rate at which energy is applied (kwh/h). The rate at which energy is applied is the power draw of the ball mill. If we then define the production per unit, of energy applied as the energy specific production rate of the circuit, then we can write the following equation:
All the production of new product size material takes place in the mill as coarse is ground into fines. However, the proportion of the total mill power applied to size reduction of coarse particles is equal to the fraction of coarse solids inventory, or the so defined circuit classification system efficiency.
The mill specific grinding rate reflects both the efficiency of the mill environment in breaking the coarse particles, as well as the grindability characteristic of the ore over the particular size reduction range.
To arrive at a term which reflects only the efficiency of the mill environment, we must factor out the grindability of the ore, such as the net grams per revolution measured in a Bond work index test. This will yield the specific grinding rate in the plant ball mill relative to the measured specific grinding rate in a standard test mill, and may be termed the grinding rate ratio.
The grinding rate ratio may be considered dimensionless because each revolution of the test mill requires a fixed amount of power. It is based on breakage of only the coarse material in both the plant ball mill and the standard laboratory test mill. It is therefore proposed that the grinding rate ratio is a direct measure of the relative overall breakage efficiency of the environment of the plant ball mill.
The above described parameters for system breakage and classification system efficiency factor the overall task of the ball mill circuit into its two distinct basic functions, namely, fines generation and fines removal. The effect of design and operating variables on each can be studied separately, and when the product of the two is maximized, maximum overall circuit efficiency will be achieved. Equation 2 may be re-written as:
This has been termed the ball mill circuit functional performance equation (McIvor, 1989). It states that the output of new product size material of a ball mill circuit with a given feed size is determined by:
a. the total mill power draw; b. the classification system efficiency, which defines the fraction of the total mill power effectively applied to the grinding of coarse material; c. the grindability characteristic of the ore over the size reduction range of the circuit; and, d. the breakage efficiency of the ball mill environment on the coarse material.
While all four factors clearly influence the circuit output, overall circuit efficiency will be determined by classification and breakage efficiency. Specific design and operating variables can now be considered in terms of their individual effects on classification and breakage efficiency, and subsequently on the overall efficiency of the circuit. This provides an intermediate level of ball mill circuit performance characterization, as shown in Figure 5.
work actively to improve productivity - news - cic luoyang heavy machinery, co., ltd
Recently, all the workers of the Special Steel Plant work hard to find ways to improve the production efficiencydue to the urgent contract delivery time.First, In order to ensure the delivery time and complete the annual production plan, the director led the maintenance workteam to carry out technical renovation of the Intermediate frequency furnace according to the usage, so as to increase the early power of the intermediate frequency furnace and speed up the smelting speed, save 15 minutes per furnace production time on average as well as increase the output and improve the working efficiency.Second, In order to improve the production efficiency, output more molten steel and reduce the cost, the smelting workteam observed the liner usage every day and timely repaired the defective parts with the limited time before the opening of the furnace, the furnace liner continued to use 114 times, that is the most ever used in the special steel plant (the average daily use of 75 times).Maintenance workteam and smelting workteam were awarded by the Special Steel Plant because of the performance of both of them in actively work, besides, the whole plant was called on to learn from them.