UTILIZATION OF OIL SHALE ENERGY AND OIL SHALE MIN IN THE PRODUCTION OF CEMENT AND HYDR BINDERS

In Dotternhausen, Germany, Rohrbach Zement has been successfully using Posidonia shale in a complex process for more than 60 years. The oil shale is rather poor with only 9 % organic matter, a calorific value of 3400 kJ/kg, an oil yield of 40–45 l/t and an ash content of 71 %. The deposit consists of a 9-m-thick flat layer of bituminous calcareous marl, which is mined in an open cast mine. The utilization of oil shale is integrated into the manufacture of cement and other hydraulic binding agents. Part of the oil shale is directly used in the precalciner of the rotary kiln for cement clinker production. Finely ground oil shale supplies 20 % of the thermal energy and 10 % of the raw minerals needed for the clinker burning process. Most of the oil shale however is burnt at certain conditions in fluidized-bed units to produce burnt oil shale with remarkable hydraulic properties. The heat of this burning process is used simultaneously to produce electricity. Hydraulic burnt oil shale is mainly used together with clinker to make Portland-Burnt Shale Cement (CEM II/B-T), according to European standard EN 197-1. But it is also suitable to produce burnt shale based binding agents for many applications in civil and soil engineering. The profitability of this oil shale operation is based on the complete utilization of both the oil shale energy and all of its minerals.