THE EFFECT OF GRINDING AIDS ON THE FINE GRINDING OF LIMESTONE, QUARTZ AND PORTLAND-CEMENT CLINKER

The effectiveness of seven grinding aids, namely triethanolamine, mono- and diethylene glycols, oleic acid, sodium oleate, sulphite waste liquor and dodecylbenzene sulphonic acid on the batch grinding of Portland cement clinker, limestone and quartz was investigated in a laboratory ball mill. The initial stages of grinding of the materials studied, without the use of grinding aids, were found to depend on their Moh's hardness. Excessive shell and ball coatings led to virtual stoppage of fine grinding of cement clinker and limestone. Quartz, which did not exhibit this property, continued to grind finer. All the grinding aids studied have been found to be effective in variable degrees. While the grinding aids had only a marginal effect on the grinding of quartz, they had significantly beneficial effect on the grinding of limestone and cement clinker. Triethanolamine appeared to be the most effective of all the aids studied. In the grinding of cement clinker, gypsum also acted as a very effective grinding aid. The action of these additives has been attributed to their ability to prevent agglomeration and ball and mill coatings of the powder.