For many concentrators, controlling grinding fineness and improving concentrate recovery are important factors for enterprises to increase benefits. So how to effectively control grinding fineness, first of all, we need to fully understand the factors affecting grinding fineness.
1. Hardness of ore: Rational ore blending can be carried out to make the ore size uniform as far as possible, and the proportion of massive and powdery ore is reasonable and stable. In addition, the belt of the ball mill may leak because of long wear and tear. Most of the leaks are fine ore. This part of the leak must be added to the ball mill as soon as possible. If it is stacked for a long time and added centrally, it will cause uneven ball milling to the ore and unstable production. Especially for refractory ores, the properties of powder minerals and lump minerals are often different.
2. Crushing size and screen hole: The ball miller must supervise the crushing system. If the feed size of the ball mill changes in production, it must be immediately reflected in the crushing workshop. Ultimately, the finer the particle size, the better.
3. Ball mill model, speed and ore feeding: Attention should be paid to consulting and communicating when purchasing.
4. Ball gradation: Ball gradation is an important factor affecting grinding fineness.
5. The lifting height of classifier spindle: After the maintenance of equipment, some ball grinders in concentrators have not cleaned up the ore sand in the classifier, and have settled down for a long time. When they put down the classifier spindle, due to carelessness, they have not put down the spindle completely, resulting in less sand return than normal. In addition, the spindle has not been put down, or it may be because the spindle has not been cleaned up for a long time, so attention should be paid to the operation process.
6. Blade wear: When the blade is worn, the grinding fineness becomes coarser relative to the amount of sand returned. In addition, if the blade is worn badly, it will affect the life of the classifier. Therefore, the wear condition of the blade is checked in time and the worn blade is replaced in time.
7. The height of overflow weir of classifier: It affects the size of deposit area of ore sand. In production, we can adjust the height of overflow weir of classifier appropriately according to the requirement of grinding fineness. If the grinding fineness is required to become finer, we can weld a certain height of angle iron along both sides of classifier. The height of overflow weir of classifier can be adjusted by inserting wood wrench method. Sometimes, after long-term accumulation of slime, it can be natural. Increase the height of overflow weir.
8. The size of the lower opening of the classifier, the size of the lower opening of the classifier, the upper opening of the classifier and the upper opening of the classifier: During the installation of the equipment, on-site production is carried out. In many dressing plants, because the size of the lower opening of the classifier is not adjusted well in the installation of the equipment, and the workers pay little attention to it in the operation process, invisibly affecting the grinding operation. The lower opening of the classifier is lower than that of the ore deposit area, so the amount of sand returned is large, the grinding fineness is relatively fine, the lower opening of the classifier is relatively large, the ore deposit area is relatively large, the flow is relatively flat, so the amount of sand returned is large, the grinding fineness is relatively fine, the upper opening of the classifier is relatively low, the amount of sand returned is relatively large, the grinding fineness is relatively fine, the upper opening of the classifier is relatively large, and the relative amount of sand returned is relatively large. Large, grinding fineness is relatively fine. Otherwise, the opposite is true.
9. Flow size at sand return: At present, grinding automation has not been realized in many mines in China. The size of water flow is adjusted manually by ball millers directly. Because the flow at these two places is large, it is difficult to see the increase and decrease of water flow, so careful observation and fine adjustment must be required.
10. Feed water size of ball mill: the feed water of ball mill increases, the grinding concentration becomes thinner, and the grinding fineness becomes coarser. On the contrary, the feed water of ball mill decreases, the grinding concentration increases, and the grinding fineness becomes finer.
11. Flushing size at discharging port of ball mill: flushing water at discharging port of ball mill becomes larger, overflow rheology becomes thinner and overflow fineness becomes finer. On the contrary, the flushing water at the discharging port of the ball mill becomes smaller, the overflow flow flow becomes dense and the overflow fineness becomes thicker. Therefore, in the case of other conditions including the same amount of ore, in order to improve the grinding fineness, the feed water of the ball mill can be reduced and the flushing water at the discharging port of the ball mill can be increased. It is better to adjust these two conditions at the same time so as to minimize the fluctuation of flotation caused by the change of the paddle volume caused by the adjustment of the grinding fineness.
After a comprehensive understanding of these factors affecting grinding fineness, it is no longer necessary to improve and maintain the grinding fineness in order to achieve the control of grinding fineness.