Process Optimization Study On Preparation Of Cement By Carbide Slag

Calcium carbide slag is a waste residue produced by the hydrolysis of calcium carbide in the process of industrial production of polyvinyl chloride,polyvinyl alcohol,acetylene gas and other products.If the calcium carbide slag is not properly disposed,it will be piled up in the open air,which will occupy a large amount of land and pollute the nearby soil and water.The use of calcium carbide slag to make cement process is to replace calcium lime with calcium carbide slag to provide calcium raw materials.This method is mature in technology and the downstream market is relatively broad.At the same time of comprehensive utilization,there are certain economic benefits.However,for large-scale chemical enterprises with an annual output of hundreds of thousands of tons of calcium carbide slag or even millions of tons,the output of calcium carbide slag is often fluctuated due to the adjustment of the upstream production load.If improperly adjusted,the calcium carbide slag will be easily damaged or the cement products will be unqualified..Therefore,it is of great significance to make timely adjustments to the ratio of calcium carbide slag and to produce qualified cement.This project takes a 2500 t/d new dry process cement clinker production line as an example.Through theoretical calculation and analysis,under the condition that other conditions are constant,and the rotary kiln operating conditions are stable and the cement products are qualified,The theoretical interval for adjusting the ratio of calcium carbide slag and waste limestone is that the theoretical interval of calcium carbide slag ratio adjustment is 55.5-81.2%,and the corresponding theoretical interval of waste limestone ratio adjustment is 0-25.7%.By collecting and arranging the changes in the chemical composition of the raw materials adjusted in the actual production 10 times,the chemical composition and the change of the yield of the clinker produced,and the quality changes of the cement products produced,and collecting and sorting the data system In the table,the influence of the ratio adjustment of calcium carbide slag and waste limestone in the raw materials on the quality of cement products was compared and analyzed.It was found that the ratio of calcium carbide slag and waste limestone was 69.2-81.2 under the same conditions.When the ratio of calcium carbide slag and waste limestone is adjusted within the range of 69.2-81.2%and 0-12%,respectively,it will not cause the cement product to fail,and will be adjusted according to this ratio in subsequent production.After the ratio adjustment,the carbide slag and the waste limestone basically reached the standard of zero emission.On average,it can reduce more than 3,000 tons of calcium carbide slag from the external slag yard,reduce more than 1,000 tons of calcium carbide slag in the open air,reduce more than 10,000 tons of waste limestone,save more than 3,000 square meters of land,and increase the economic benefits by more than 1.4 million yuan;At the beginning of 2018,more than 700 tons of recycled calcium carbide slag were recovered.The land occupied by the factory and the surrounding environment have been significantly improved.Therefore,the ratio of calcium carbide slag and waste limestone is adjusted in the range of 69.2-81.2%and 0-12%,respectively,to achieve the expected effect,with good economic and environmental benefits.