Study On The Effect Of Alkali Metalchloride To The Treatment Of Zinc Containing Cust By Direct Reduction

The deposition of flue gas and the waste of valuable substances such as zinc in raw materials have become a major constraint on the development of rotary hearth furnace.This behavior by exploring the direct reduction of alkali metal chloride,as well as the influence of the content in the raw materials are caused by changes in the flue gas of zinc containing matter deposition and reduced metal pellets,using theoretical analysis and experimental research method of combining research on treatment effect of alkali metal chloride zinc bearing dust and sludge process caused by direct reduction method.Through theoretical analysis of alkali metal chloride in reduction of metallurgical dust and slag in the process of the behavior of the KCl under the condition of high temperature steam pressure,gasification rate is far higher than NaCl,when the T=1250 ?,KCl saturated steam pressure is 11.25 kPa ideal gasification speed 0.718mm/min,and NaCl for 0.326mm/min and 5.87 kPa.In the process of raw material reduction,the alkali metal chloride reduced the Gibbs free energy of the zinc reduction reaction and promoted the reduction and removal of zinc in the raw material.In the heterogeneous nucleation process of zinc containing substances in flue gas,alkali metal chloride reduces nucleation energy during nucleation,and promotes the nucleation and aggregation of zinc bearing substances,resulting in the precipitation and deposition of more zinc.The zinc containing metallurgical dust and sludge were used as raw materials to prepare reactants by self distribution of carbon.The high temperature tubular furnace was used to carry out the deposition experiment.After analyzing the tail gas components,the zinc bearing sediments from different deposition periods were extracted and their morphology was observed.The experimental results show that the alkali metal chloride in the sediments showed regular distribution of NaCl after KCl,reached the peak when the sediment growth speed in atmosphere CO content,KCl ratio decreased in surface sediments,sediment surface alkali metal chloride after the reaction with NaCl.After adding alkali metal chloride to zinc containing dust and zinc,the effect of alkali metal chloride on the quality,morphology,structure and composition of sediments was investigated.The results showed that the total mass of the sediments increased and the total sediment quality increased from 600-800 to 1.5 when the addition times of alkali chloride increased from 0 to 1.5 times.The proportion of total sediment quality increased from 30.49% to 53.33%.The removal rate of Zn elements in the raw materials increased from 96.73% to 98.25%,and the deposition ratio in the enriched region increased from 37.21% to 72.43%.Alkali metal chloride in sediments reduces the surface energy of sediment particles,forming a large amount of alkali metal chloride Zinc Oxide composite phase with ZnO particles,which makes sediment structure more dense at the same time of increasing thickness.Through the investigation in the same proportion to add only the results of a group of alkali metal chloride showed that only after the addition of NaCl,the quality of the sediment enrichment zone,sediments,sediment quality enrichment ratio,removal of zinc in the raw material adding rate is much higher than the KCl group,NaCl for direct reduction of metallurgical zinc bearing dust and sludge process is far greater than the KCl.