Abstract: Aiming at the large crushing capacity of a fine crusher in a concentrator and the coarse grain size of the ball mill feed， by reducing the sieve size of sieve plate in a concentrator， the fine grinding and sieving operation， primary and secondary ball milling classification were examined under the conditions of producing sieve plate （sieve size 14 mm×20 mm） and test sieve plate （sieve size 10.0 mm×40 mm） respectively. The results show that the content of -12.0 mm in fine screening and grading products increased from 88.09% （F95=15.20 mm） to 98.71% （F95=10.31 mm）.When the first stage milling capacity is 295 t/h， 310 t/h and 325 t/h， the particle size content of -0.074 mm in the second stage graded overflow increases from 79.86% to 86.86%， 77.03% to 87.68% and 75.63% to 84.45%， respectively. After the sieve plate was replaced， the particle size of the fine screening product and the secondary graded overflow product are significantly thinner. The optimization of crushing and sieving process gives full play to the crushing ability of crusher and reduces the feed size of ball mill.

Key words: Fine crusher, Crushing capacity, Sieve plate comparison, Grinding classification