A good product shape should ensure that the ratio of the maximum size to the minimum size of more than 90% of the product is less than 3 (the smaller the ratio, the better the shape), and the number of samples should not be less than 300 when sampling. The product size of the crushed material is determined by many factors. But its main influencing factors are concentrated in the aspects of feeding, crushing cavity type, discharge port, crushing equipment and crushing technology.

(1) Correct feeding

The multi-cylinder cone crusher must achieve full-cavity feeding (the material is 300mm higher than the distribution tray), and the feeding can be interlocked with the level sensor, and the feeding bin can be built to achieve full-cavity feeding. The stable continuous grading feed can avoid the change of the crushing power and the feed gradation break, while maintaining a relatively stable crushing cavity and discharge port. The product grain shape obtained by the wide gradation feed is better than the narrow gradation feed. The part of the feed material that is smaller than the discharge opening will increase the squeezing effect between the materials and have a good filling effect in the crushing cavity. It should not be too thin, preferably slightly less than or equal to the size of the discharge opening, and the proportion should not be 20%. A large discharge port will bring more flake products, so in order to obtain a good product shape, a smaller discharge port is required, and the crushing ratio is controlled at 3 to 3.5. This requires good control of the feed size, preferably not more than 50mm. Unsatisfactory feeding will result in a series of problems such as a decrease in the capacity of the crusher, a jump of the adjusting ring, a shortened service life of the lining board, and a poor particle shape of the crushed product.

(2) Accurate crusher and crushing cavity

For fine crushing, a 10/50mm feed, compared with spring cone crusher, the multi-cylinder cone crusher can obtain better grain shape, which can achieve the effect of vertical shaft shaping. As mentioned above, the small crushing cavity can set and maintain a smaller discharge opening, so it is easier to obtain a good particle shape with a small crushing cavity.

Power, crushing force and discharge port are the three major factors that determine the output and fineness of the multi-cylinder cone crusher: The way to increase the power is to increase the feed rather than reduce the discharge opening. The best crushing power is about 80% of the rated power. The jump of the adjustment ring is the most obvious and intuitive performance of the super-crushing force of the multi-cylinder cone crusher, that is, the jump of the adjustment ring means that the crushing force exceeds the design limit. Once the crusher has an over-crushing force, the discharge opening can be adjusted to 1mm~2mm . The adjustment limit of the discharge opening is not to cause the adjustment ring to jump and avoid power peaks. Adjusting ring bounce and power peaks will add extra stress to the crusher, which will eventually cause serious damage to the crusher.

(3) Closed loop and crushing system.

The crusher is a part of the crushing system, and other equipment will also affect the entire crushing system.

The mineral conveying system must have sufficient conveying capacity. Whether the storage bin in front of the crusher is buffered is very important for the stable filling and feeding of the crusher. Small bins can solve big problems. The level of screening efficiency has a huge impact on the crushing system. Insufficient screening, on the one hand, causes too much fine material in the return material, which is easy to cause the crusher to overload; on the other hand, too much qualified fine material is returned to the crusher, which reduces the production capacity of the crushing system.

The non-crushing foreign objects in the crushing system can cause great damage to the crusher. For example, over iron may cause the crusher to burn the copper sleeve, the frame cracks, and the main shaft breaks. Closed circuit crushing, used in the second stage crushing, can provide precise small feed size for fine crushing, avoid excessive fine materials from entering the crushing cavity, and achieve the ideal filling effect of the crushing cavity. Used in fine crushing can improve continuous feeding gradation and improve product quality.

(4) Material characteristics and product granularity.

Generally speaking, the softer the rock, the thicker the crystalline particles of the rock, the thicker the product, and the better the broken grain shape. For example, to obtain 6-15 products. The second-stage crushing adopts a closed loop to crush to below 50, and screen out the material below 6mm to ensure that there is a stable 6-50 continuous grading for fine crushing. For fine crushing, choose a multi-cylinder cone crusher with short head cavity, 13~15 discharge ports, and closed-circuit crushing.