低温熔盐炼铅产物在热态熔盐中的沉降分离研究

Study on Settlement and Separation of Products in Hot Molten Salt during Process of Lead Smelting in Low-temperature Molten Salt

研究了低温熔盐炼铅产物中固态物颗粒和液态铅珠在Na2CO3热态熔盐中的重力沉降规律,优化了固态物和熔盐的沉降分离条件。结果表明:液态铅珠、ZnS和ZnO固态物颗粒在热态熔盐中的沉降速度顺序为Pb>ZnS>ZnO,且温度升高沉降速度加快。但温度超过900℃后,ZnS和Na2CO3反应生成ZnO的趋势增大,不利于ZnO的固硫,因此沉降温度不宜超过900℃。在盐固比为2.8、温度900℃和保温3h的条件下,熔盐渣中超过80%的ZnS和ZnO固态物颗粒可沉降到反应器底部,实现与熔盐的热态分离;92%以上的液态铅能在较短时间内聚积到反应器底部,残留于表层熔盐中的铅小于2%。

Gravity settlement regularity of solid particles and liquid lead beads in hot molten salt was studied and settlement and separation conditions of solid and molten salt were optimized.The results show that sequence of settling velocity about such solid particles,i.e.,ZnS,ZnO and liquid lead beads,is Pb>ZnS>ZnO,and settling velocity rises with increase of temperature.Settling temperature should not be higher than 900℃because trend for reaction between ZnS and Na2CO3 to produce ZnO will rise which is bad for sulfur-fixation of ZnO.More than 80 percent of ZnS and ZnO particles settle to bottom of reactor to realize hot separation from molten salt under the conditions including salt solid ratio of 2.8,temperature of 900℃,and heat preservation time of 3 h.More than 92 percent of liquid lead can be settled to bottom of reactor within a short time and less than 2 percent of lead remains on surface of molten salt.