Investigation Of Piston Press Test And Static Press Work Index For Ores

The high-pressure grinding rolls(HPGR)is a comminution equipment developed on the basis of the lamination pulverization theory,its application method is supplemented by laminating pulverization.Compared with traditional cone crushers,jaw crushers and other traditional crushing equipment,HPGR has outstanding advantages such as increasing production and reducing consumption,improving mineral dissociation degree,improving grinding efficiency,high single machine output and good reliability.The promotion and application of HPGR in the field of mineral processing can effectively promote technological advancements in the industry and contribute to energy conservation and consumption reduction.At present,the main problem that hinders the promotion and application of HPGR in the field of mineral processing is that the selection test of HPGR lacks a simple and reliable method.Each project needs to carry out the corresponding pilot test of HPGR,the test process is labor-intensive,time-consuming and costly.Piston press test is an important experimental basis for the invention of HPGR technology.This paper summarizes the working principle,structure,working process and application status of HPGR.The test method,working principle and application status of piston press test are analyzed.The relationship between the particle-bed comminution test and the process performance of the HPGR was explored.In this paper,a special piston-cylinder die with a diameter of 75mm was used to carry out piston press test on three kinds of ore materials by hydraulic pressure tester.The test conditions mainly include the ore size(0mm-12mm),the feed amount.(1.5Dmax-4.5Dmax),water content(0%-6%),loading pressure(30Mpa-180Mpa),loading speed(0.1mm/s-0.3mm/s).Based on the third comminution theory of Bond,a mathematical model was established based on the experimental results,and the work index of the HPGR of the industrial HPGR was predicted by the piston press test.The results show that with the increasing of loading pressure and energy consumption,they have a good linear relationship;the crushing ratio increases with the increasing of loading pressure,and the increasing rate of crushing ratio decreases or stabilizes after the pressure increases to a certain extent.With the increasing of the feed size,under the same pressure conditions,the specific energy consumption on the material is gradually reduced,and the crushing ratio is gradually reduced.The increasing of the feed size is more than R80 for the change of R50,and R80 is more stable.As the amount of material increases,the trend of negative cumulative yield curve is steeper and slower,and the slope of the curve increases obviously.The larger the amount of material,the smaller the variation of the curve,the lower the negative cumulative yield,the lower the amount of newly generated product;As the amount of material increases,the specific energy consumption decreases,and the crushing ratio decreases.With the increasing of water content,different types of ore are affected differently and the negative cumulative yield of gold ore decreases.With the increasing of water content and feeding size,the negative cumulative yield of vanadium-titanium magnetite decreases slightly increasing.On the basis of obtaining the suitable crushing pressure of the piston press test,the closed-circuit cyclic ballast process was used to simulate the three-stage crushing process of "press compaction,particle-bed crushing and expansion agglomeration" of the HPGR by piston press test.According to Bond's third pulverization theory,the calculation formula of the work index of HPGR is established.The key parameters are derived by smashing the net input power of the same ore by pilot test or industrial HPGR.The final formula is W_i=2.035/(pi0.321 Gsp0.0293((?)).Using this formula,the static press work index of the HPGR can be derived from the results of the particle-bed piston press test,and the error can be controlled within 15%.This paper provides laboratory basic data for the selection test of HPGR,which has important theoretical significance for the promotion and application of HPGR.