The influence of additives during wet ultra-fine grinding in agitator beadmills part I: General principles and experimental

Additives that increase the repulsive interactions between particles can im prove the flowability of a suspension. Thus, at constant energy and a highe r solids concentration the mill throughput can be increased. On the other h and, with a constant solids concentration and equivalent end fineness, cons iderable energy savings can be achieved or, respectively, a significantly h igher product fineness at constant specific energy can be realised. The ext ent of the effects that are seen through the addition of additives in wet f ine grinding are determined by: the solids concentration, the particle size and thus the distance between the particles the stress intensity the particle interactions in the initial condition the possible impurities in the product (through wear from the grinding bodi es or walls of the mill) that go into solution, thus altering the particle interactions during grinding the amount of energy loss due to viscosity with respect to the total energy used. Experimental investigations were made on two different model substances (li mestone and corundum) with the addition of a number of inorganic and organi c additives. The relationship found between the particle interactions, rheo logical properties and comminution parameters are of interest, primarily in grinding techniques in nano-technology, since only through the addition of appropriate additives can a very large percentage of particle sizes in the range <1 <mu>m be achieved.