What if the ball mill output is getting lower and lower?Date: 2019-07-01 Views:
When we buy a ball mill, the manufacturer's instructions will have detailed technical parameters, and generally give a range of production values. Usually, the output will remain normal when the ball mill is just put into production, but after a period of operation, there may be a situation where the output is getting lower. What is the reason why the ball mill output is getting lower and lower?
Ball mill "saturated"
When the output of the ball mill is getting lower and lower, the first thing to consider is whether there is “saturated grinding”, which is the main culprit influencing the output of the ball mill.
The reasons for “saturated grinding” are: too much feeding; the hardness of the grinding material becomes hard and the particle size becomes large; the moisture of the grinding material is too large; the steel ball gradation is unreasonable; the partition board or quilting is mixed The object is clogged.
The solution to the problem of “saturated grinding”: reduce the feeding amount; when the size or hardness of the grinding material changes, it should be adjusted accordingly; adjust the moisture of the grinding material; reasonably configure the ratio of large, medium and small steel balls; Blocking the slats or quilting; increase the ventilation of the ball mill cylinder.
Ball mill working time is too long
The length of the ball mill directly affects the product composition and purity, and the ball milling time has a significant effect on the particle size. In the initial stage, the particle size drops rapidly with the extension of time, but after the ball is ground for a certain period of time, even if the ball milling time is extended, the particle size of the product will not decrease much. Different samples have different optimal milling times. On the other hand, the longer the ball milling time, the more serious the pollution, which affects the purity of the product.
Did not add steel balls in time
The grinding effect of the ball mill and the output of the ball mill are restricted by the ball of the ball mill. However, with the grinding and impact of the barrel, the steel ball will wear, so it is necessary to add the steel ball in time to ensure the maximum output of the ball mill. Consistency.
Increased temperature inside the cylinder
When the ball mill is running, the temperature rises, the effective strain of the nano-material formed by the ball mill is reduced, and the grain size is increased, which significantly affects the mechanical properties of the powder-made block. Moreover, whether the final product of the ball mill is a solid solution, an intermetallic compound, a nanocrystal, or an amorphous phase, the diffusion problem is involved, and the diffusion is affected by the grinding temperature, so the temperature is also an important factor affecting the output of the ball mill.
Material moisture content is too high
Due to the large moisture content of the material, the uniformity of the feed is affected and the feeding time is prolonged. Secondly, due to the excessive feeding of wet materials, it may cause the phenomenon of paste paste and paste liner in the mill, and even “saturated” and forced to stop grinding. In general, for every 1% increase in the integrated moisture content of the milled material, the ball mill output will be reduced by 8%-10%; when the moisture is greater than 5%, the ball mill is basically unable to perform the grinding operation.
The proportion of grinding aid is not reasonable
The national standard stipulates that it is allowed to add grinding aid in the cement production process, but the addition amount should not exceed 1%. It is unreasonable to add more than this standard. In addition, most of the grinding aids are substances with strong surface activity, which are not suitable. All materials should be reasonably added according to the nature of the materials.
二、[Technical Q&A] How to determine the ratio of ball mill loading
Use the "Golden Section" to determine the rate, that is, the ball: material: (water + air) = 1.618: 1: 0.618; "golden segmentation" is an optimal principle of distribution, in fact, everything is in pursuit of harmonious beauty, ball and ball The ratio of water to air is no exception. However, the distribution ratio according to the golden section is the theoretical ratio and the optimal ratio. The actual situation is also determined according to the raw materials, the ball stones, and the mill conditions.
The raw materials include a main raw material and an auxiliary raw material, and the auxiliary agent includes a water reducing agent, a reinforcing agent and a grinding aid, and sometimes the grinding aid and the water reducing agent are integrated. The main raw materials are also divided into three categories, namely, ridge raw materials, medicinal raw materials and plastic raw materials, and the spine of the spine is also commonly known as skeleton raw materials, such as silicon aluminum. Agent flux is also commonly known as low temperature fluxing materials, such as feldspar, mica, wollastonite, diopside, dolomite, limestone and the like. The molder also shapes, meaning plastic and sticky raw materials, such as kaolin, bentonite, processed ball soil. In fact, there is no obvious difference between the three, and most of them have crossovers, which belong to them and belong to this. The raw materials that are more difficult to grind are actually some natural hard ore. Generally, the raw materials entering the stockyard are divided according to the form, stone powder, stone, sand, soil and mud. The materials that are more difficult to be ball milled are concentrated in the first three, namely stone powder and stone. And sand, especially the stone with large grain size and high hardness is the difficulty of wet ball milling. In the north, due to the addition of a hard block of hard clay such as alkali rock, a large size ball stone is artificially introduced. A typical case. Plastic raw materials, auxiliaries, water and air are the agents that help these hard materials to suspend, adhere, wash and peel. With the help of these agents, the efficiency is improved.
Using the pyramid principle and the "golden segmentation" rate to determine, consider the radial dynamic motion of the ball mill, small ball stone: medium ball stone: large ball stone = (1.618 +1 + 0.618) 2- (1 + 0.618) 2: (1 + 0.618) 2-0.6182: 0.6182, converted to a percentage of: small ball stone 75%, medium ball stone 21.35%, large ball stone 3.65%.
Ball stones include natural and artificial. Natural stone is ochre pebbles. Its shape and defects affect efficiency, so many factories have begun to use artificial ones. Artificial ball stones are actually quite a lot, such as artificial ochre pebbles, medium aluminum balls (including mechanism and manual) and high aluminum balls, but high aluminum is rarely used for the preparation of green powder, used for high white and high. The fabric is still required. Artificial ochre pebbles are the only things that have appeared in ceramic factories in recent years. There are two reasons. One is that the lining lining processing plant processes the lining scraps into ball stones for comprehensive utilization, and the other is natural shale. The pebbles are indeed less. For the most widely used medium-aluminum ball and ochre pebbles, it should be treated differently.
The medium-aluminum ball is divided into 60 balls and 70 balls with alumina content, that is, porcelain balls with an alumina content of more than 60% and porcelain balls with an alumina content of more than 70%. The manufacturing method is divided into manual balls and mechanism balls. There is a big difference, be careful when buying and using. The table below lists their differences and selection quality points.
The total amount of ball stones is related to the composition of the formula. If the formula is better, the water can be controlled to reduce the value, then either the tonnage of the ball material can be increased, or the toll of the ball can be increased, that is, the 60-ton ball mill is loaded. The dry weight of the material is not necessarily 60 tons. It is recommended to adjust it according to the proportion and hardness of the hard material.
Compared with the medium aluminum ball, the ochre pebbles are irregular in diameter and shape, and because of the low specific gravity, low hardness, and easy cracking, the ball is generally 40mm, 60mm, 70mm, and the ratio is 4:3:3. .
In short, the ball water-air ratio and the large, medium and small ball stones have rules to follow, based on the principle of "pyramid" and the principle of "golden segmentation". But it can't follow the old rules and seek the best value in the change. The hardness, specific gravity, shape and gradation of the ball stone and the moisture and viscosity changes of the mud constitute the energy-saving dynamic system of the wet ball mill. The so-called dynamic refers to energy saving in sports, and sports actually have macroscopic and microscopic, macroscopic refers to ball mill, microscopic refers to grinding aid. Therefore, "one dose, one machine, one ball, one water, four integrations" form the wisdom of ball mill energy saving.
If your ball mill output is getting lower and lower, you can check it out according to the above reasons, find the crux of the problem, completely solve the problem of low output from the root cause, and resume production as soon as possible.