Improving Grinding Efficiency Of Ball Mills
If the ratio of ore and water is too large, the viscous slurry would slow down the rotation of ball mill, and as a result, the grinding efficiency of grinding media will be decrease. But if the ratio is too small, the thin slurry will lead to the direct impact of the grinding media to increase the wear and tear of the grinding body, also cause increased evaporation in the spray-drying process, which could waste the fuel and decrease the discharging ratio of spray drying tower. Usually for ore containing more plasticity raw materials, the ratio is smaller; the ratio should be larger is more barren raw materials are contained.
The grinding medium and materials within the ball mill have three kinds of moving states because of the different rotating speed of the ball mill: drop motion; throwing motion; centrifugal motion. The normal working states of ball mills are drop motion and throwing motion. According to the observation, the more close to the ball mill cylinder, the more the amount of the grinding medium. Only making full use of the outermost layer of the material can make the maximum efficiency of the ball mill. By the theoretical calculation that, when the outermost grinding media detachment angle of 54.73 °, the outermost layer can obtain the maximum falling height of the material in the most effective pulverization. Found from the actual operation, when the operating speed of the ball mill is adjusted to critical speed of 0.75 to 0.85, the grinding medium could reach higher place.
In the ore separating line, the ball in a ball mill is continuously worn. In order to maintain a stable operation of the ball mill and to maintain a reasonable ratio of the filling rate, balls must be reasonably complemented. Reasonable complement of balls is one of the key issues to improve the efficiency of the grinding process. Regularly check the ball mill in accordance with its actual situation, accumulate data, revise the ratio, and finally reach a stability ball charge ratio and reasonable purpose of the complement ball. Normal complement ball only refer to a large ball, and users do not make up a small ball, because the ball can be worn by the big ball. In summary, select the best rotation speed of the ball mill, filling rate and high-quality steel ball, and be careful to draw the ore particle size characteristics curve, in order to determine a suitable size of the steel ball, ball ratio, and gradually mastered the production complement ball law is an effective way to improve the ball mill efficiency. ■
The Ball Mill Grinding Process
The ball mill is one of the important equipments in the ore separating line. According to the scale of production and conditions of usage, there are a variety of different models of ball mills. As for the ceramic industry, due to the special nature of the production process, ball mill is always a wise choice because of its single structure, easy maintenance, flexible terms, etc. Ball mill is widely used in the ceramic industry, but it may be unstable in the process of using a ball mill, which will have a great influence on the process control and product quality.
The grinding operations are mostly done in cylinders with grinding medium. The continuous rotation of cylinders brings the grinding medium to a certain height, then falling down because of gravity. In this way, the impact strength is produced. At the same time, due to the grinding media revolution and rotation along the cylinder axis of the cylinder body, the squeezing and grinding force generated in contact with the cylinder interval between the grinding media, so that the ore milled. The grinding job with water is called wet grinding, and the dry grinding doesn’t need to feed water. The grinding operations use harder and larger proportion of forged steel (or steel) manufactured into balls and long stick, sometimes using gravel ground softer ore.
The raw materials in ceramic industry can be roughly divided into plastic and implastic materials. The crushing degree of various materials is different, either is the granularity, so if hard materials and soft materials are put into the ball mill together, the clay with small granularity will form a thin mud cover on the surface of the raw feldspar and quartz, which could decrease the grinding ability of grinding medium, lead to the over grinding of soft materials, and extend the grinding time. During the grinding process, the materials that are hard to be crushed should be fed first to shorten the grinding time and improve the grinding efficiency. In abroad, some people will grind the hard materials and soft materials separately, and then mix the slurry according to the requirements. But this process also has its shortcomings, and the mixture of raw materials could be uneven ■