الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
The introduction discusses cement chemistry and main phases of cement. Review of cement hydration process and reaction products to further clarify role of calcium sulphate in cement as a set regulator and sequence of reactions of ettringite formation.
The introduction included also review of vertical mill history and its development with time. Application of vertical mill in cement grinding with clarification for the geometry of the mill’s grinding parts. Vertical mill operation parameters that are used for controlling the quality of cement such as separator speed, air flow rate, grinding pressure and dam ring height. Problem of gypsum dehydration was added which is accompanied with vertical mill and the proposed options to handle such problem like cooling cement, replacing gypsum with anhydrite and increasing mill temperature.
Finally, presenting aims of the study from investigating reasons of lump formation inside silo with the proposed solution and study the impact of replacing gypsum with anhydrite on cement characteristics in vertical mill.
Chapter (2)
This chapter presents importance of cement and history of cement formation. Process of cement production starting from raw materials to cement product. Details of clinkering process with the kiln reaction zones and reactions inside the kiln to form clinker. Moving after to cement grinding step and presenting mill types that are used for grinding cement with the advantages of vertical mill. More deep discussion of role of gypsum in cement production and its different forms.
Chapter (3)
Chapter three illustrates technical results of replacing gypsum with anhydrite in a vertical mill. The results confirmed that using the proper ratios of both helped in controlling cement setting and moisture of cement samples as anhydrite accelerated the hydration reactions and reduced the setting time, Initial and final setting time decreased by 5 min with 1% increment in anhydrite content. Improvement in cement storage was recorded also as a result of using mixture of gypsum and anhydrite with following percentages 50:50 % and 25:75% since the total quantity of gypsum water was reduced. Study of the impact of rising vertical mill operation temperature was added as its one of the proposed solutions to increase gypsum dehydration, increasing the outlet temperature was associated with loss of cement production and high power consumption so using a mixture of gypsum and anhydrite was better than increasing the outlet temperature. According to test results cement producer can avoid silos coating and build ups which cause problems in cement extraction from silos, waste time in silos cleaning, disturb workflow, increase production loss and lead to frequent end consumer complaints with no extra cost by blending gypsum and anhydrite.
Chapter (4)
According to the evaluation of the proposed solutions for handling coating and build up problems in cement silos, it was concluded that the blending gypsum with anhydrite was the most suitable solution in addition to the recorded improve in cement characteristics.