Discussion and application of ball mill in preparation of particle size samples of fine grained sedimentary rocks

Abstract

The grain size of clastic rocks is one of the most important structural characteristics of clastic sediments, which can directly reflect the hydrodynamic conditions of ancient sedimentary period. The preparation of conventional clastic rock particle size samples is usually done by hand wet grinding with a grinding hammer by experienced experimenter. For the fine-grained sedimentary rocks, the conventional method for preparing grain size samples has the disadvantages of long time and low efficiency. This paper introduces a method of preparing grain size samples of fine grained sedimentary rocks by separating rock particles with ball mill. By carrying out the experiments of separating rock particles by ball mill, the influence of different sample quality and ball mill parameters on the particle size and particle size distribution of fine grained sedimentary rock in the process of rock particle fragmentation by ball mill was discussed. The conditions for separating particles of fine grained sedimentary rocks by ball mill are determined as follows: sample mass is 0.14 g ~ 0.20 g, ball mill frequency is 10 Hz, ball milling time is 3 min, the efficiency of particle size sample preparation is greatly improved. The final particle suspension samples were tested by laser particle size analyzer, and the particle size distribution characteristics of fine-grained sedimentary rocks were given, which provides a basis for the study of lithology classification, lithofacies characteristics and hydrocarbon reservoir heterogeneity, and plays an important role in the exploration and development of unconventional oil and gas.