Research And Application Of Grinding Dynamics Of Yiliang Lead-zinc Mine Based On Response Surface Method

In order to optimize the grinding conditions of Yiliang Pb-Zn ore processing plant,this paper focuses on the grinding kinetics research and application of response surface method based on four factors affecting the grinding kinetics parameters:media ratio,media filling rate,grinding concentration,and ball mill rotation rate.Firstly,the m and k values of the grinding kinetic equations are independent of the time unit,they are determined by the nature of the material being ground and the grinding conditions.m value mainly depends on the homogeneity and strength of the material being ground and the ball charge size characteristics(grinding media ratio),and k value is mainly determined by the grinding size.The size distribution of grinding cycle products and ore mechanics at the site are tested and analyzed,and the maximum size of the media is calculated based on the mechanical properties of the ore and the size distribution of the grinding cycle products,and the best media proportioning scheme is determined by using scientific methods and three control schemes are established for the biased large scheme,the biased small scheme and the site scheme for laboratory tests,and the test results show that the initial ball loading scheme is ?80:?60:?40:?30=20:25:25:30?Different grinding conditions also affect the grinding kinetic parameters,and there is no obvious linear relationship between different grinding conditions,and the response surface method is needed to model the grinding conditions to establish a linear relationship to help us determine the experimental grinding conditions parameters to improve the accuracy help us find the best conditions for the problem and provide a theoretical basis for practical production.Secondly,three more important factors influencing the grinding conditions,media filling rate(A),grinding concentration(B),and ball mill rotation rate(C),were selected to model the coarse grain grade content reduction yield using the response surface method.The results of the multiple linear regression equations using Design-expert to establish the relationship between media filling rate,grinding concentration and ball mill rotation rate and the coarse-grained content reduction yield of the grinding product were.y=-1290.34125+17.88867A+8.95975B+17.87645C-0.012833AB+0.0065AC+0.0026BC-0.26117A²-0.05892B²-0.11512C²The recommended factor conditions were:media filling rate(A)of 33.42%;grinding concentration(B)of 74.15%;ball mill rotation rate(C)of 79.42%;and the predicted value of 50.5977%given by the response surface method.In the validation test under the recommended factor conditions,the coarse grade content reduction yield of 50.53%differed from the predicted value by 0.0677%,and the difference between them was small,indicating that the optimized grinding conditions were more suitable for the grinding operation and serving as a reference basis for optimizing the grinding conditions of the grinding kinetic parameters.Finally,the experimental study of grinding kinetics between the on-site grinding conditions and the recommended grinding conditions(optimal media ratio and recommended factor conditions)was carried out,and it was concluded that the effect of the kinetic parameter k value on the rate of coarse-grained grade being ground was greater than the m value,i.e.,the k value of each narrow-grained grade of the recommended scheme was greater than the k value of the on-site scheme,indicating that the rate of grinding coarse-grained material was greater for the recommended grinding conditions than for the on-site grinding conditions.The kinetic equation of grinding for the recommended scheme is R=R₀10^{-(0.01341+0.18333d-0.12558d2)t1.56339-S.00951d+16.27966d2-11.3558d3}The analysis of the grinding product size under each time period of the two schemes shows that in the process of increasing grinding time,the grinding rate of coarse grade material gradually increases at first due to the large coarse grade content of the material being ground,and the increase rate of the recommended grinding conditions is greater than that of the on-site grinding conditions.With the increase of grinding time,the coarse grinding rate decreased due to the decrease of coarse grade material content,and the grinding rate of recommended grinding condition and field grinding condition decreased gradually with the increase of time,but the yield of intermediate grade of grinding product(-0.15+0.010mm)of recommended grinding condition was larger than that of field grinding condition,and the coarse grinding rate decreased during the grinding time of 3min,6min,9min,12min and 12min.The recommended grinding conditions are 5.43%,4.70%,3.40%,1.33%and 0.02%larger than the on-site grinding conditions for the intermediate particle yield(-0.15+0.010mm)at grinding times of 3min,6min,9min,12min and 15min,respectively,which shows that the recommended grinding conditions are more suitable for on-site grinding operations.The recommended grinding conditions applied to ?3.2×4.0m lattice ball mill and 2.4m double spiral classifier to form a closed-circuit industrial test,industrial test results show that:after the industrial test than before the industrial test a series of average unit power consumption decreased by 5.6%,the second series of average unit power consumption decreased by 6.7%;after the industrial test than before the industrial test unit ball consumption decreased by 15.23%.After the industrial test,the content of-0.15+0.01mm particle size increased by 13.35%and the content of-0.15+0.01mm particle size increased by 9.07%compared with that of a series before the industrial test.