CLINKER COOLER PERFOMANCE, CEMENT GRINDING PROCESS AND WATER CONSUMPTION: A CASE STUDY OF BALL MILLS

Clinker cooler determines the life span and the efficiency of any cement grinding station. Clinker is cooled by injecting fresh cold air into the cooler via a series of fans across the layer of hot clinker. The recovered heat (air) during this process are reused for the pyro-processing, that is, the main burner uses secondary combustion air in the rotary kiln and pre-heater uses the tertiary air. Inadequate heat recovery from the clinker resulted in use of larger volume of water at the cement grinding stations, thereby increasing operating and maintenance costs and the loss of revenue. This paper assessed the effect of inefficient clinker cooler at cement grinding plant and its water consumption. The cement grinding stations, are places where the clinker and other additives are been milled to the final products known as powder cements. The grinding process includes: (ball mill), milling chambers, liners, grinding medias clinker and other cement additives. The ball mill rotary in a circular form, whereby causing a frictional forces insider the mill. The impact of the frictional forces between the grinding media balls, liners, and the raw materials inside the cement milling chambers increases the material temperature from 85 oC to temperature above 121 oC. The rise in material temperature inside the milling chambers necessitates the high volume of water consumption (7300 liters per hour). This high volume of water was used to maintain the cement outlet temperature below 122 oC. It was observed, that the excessive use of water in quenching the material temperature, recorded a huge negative impact on the storage facilities and other critical operating equipment. For the ball mills to work effectively and efficiently, the exiting clinker temperature from the clinker cooler most be less than 100 oC and the cement mill clinker weigh-feeder temperature most less than 68 oC.