Physical and chemical characteristics of cement produced with different ratio of Zn, Cr, and Ni in pilot-scale rotary cement kiln

Abstract

Co-processing between waste and raw material in cement plant was the one method to reduced concentration of the waste and decreased consumption of raw material and fuel. However, the heavy metal in waste made the effect to cement properties. This study investigated the physical and chemical characteristics of various mixtures of cement clinker. The 2.5% of mixture between shale core and clay was added in the raw meal for made the samples suitable in burning process with one meter of the pilot-scale rotary cement kiln. From the study, different ratio of Cr in raw meal did not make the effect moisture content and loss on weight in ignition process. When compared with control, high concentration of Cr increased percent free lime but decreased percent C3S and compressive strength in the clinker phase. Cr reacted with Al to get calcium aluminum chromium oxide. Likely to Cr, different ratio of Ni did not make in moisture content and loss on weight in ignition process of raw meal. In contrast, high concentration of Ni reduced percent free lime but increase compressive strength in clinker phase. Ni reacted with Mg to get Magnesium nickel oxide. High concentration of Zn in raw meal increased moisture content and loss on weight in ignition process of raw meal. High concentration of Zn reduced free lime in clinker phase. High concentration of Zn also increased concentration in both C3S and C2S. The Zn made the effect in setting time of cement mortar and created high compressive strength in 28 days. Zn reacted with other heavy metal included Fe, Mn, and Cr to got zinc iron manganese chromium oxide. From the leaching test, the all of different ratio of each three heavy metals still in the range when compared with Thai standard.