The kinetics of batch wet grinding of quartz from a feed of 600 x 425 mum to a product of 80% less than 8 mum have been determined using sieving and laser diffractometer sizing for size analysis. A dispersing agent was added while proceeding to longer grinding times to prevent particle agglomeration in the mill. The specific rates of breakage (S-i) values obtained were higher than those of dry grinding of quartz at the same experimental conditions, but the primary breakage distribution (B-i,B-j) values were the same. Non-first order grinding was observed with continued decrease of the specific rates of breakage for finer grinding. The simulations of the product size distributions were in good agreement with the experimental data, providing the decrease in rates was included. (C) 2001 Elsevier Science S.A. All rights reserved.