[Characterization of lead size distributions with different process in lead-zinc smelter]

Using a cascade impactor (Andersen Series NVA-800), the size-segregated atmospheric particulates were collected daily and characters of lead contents and size distribution in the particles were analyzed from melting preparation, blast furnace smelting and lead-cast processes within a lead-zinc smelter in Shaanxi province. The results showed that emissions of particulate matter were different in different processes, in which the emissions of blast furnace smelting process was 402.83 mg x h(-1), while melting preparation were 182.71 mg x h(-1) and 100.03 mg x h(-1) in lead-cast processes. Lead contents in different sizes of particles varied in different processes. The mass fraction of lead were 111.54 mg x kg(-1), 68.54 mg x kg(-1) and 10.5 mg x kg(-1) in melting preparation, blast furnace smelting and lead-cast respectively. For lead's size distribution, the melting preparation and blast furnace smelting were mainly concentrated in the coarse particles, and the lead proportion in coarse and fine particles was approximately in lead-cast processes. The proportions of lead in coarse particles were 43.42% and 47.48% in melting preparation and blast furnace smelting process respectively, while the proportion of lead in coarse and fine particles was 37.14% and was 45.72% in lead-cast processes. There had peaks in both coarse and fine particles of melting preparation and lead-cast process, but the lead peak appeared only in the coarse particles of blast furnace smelting. It also indicated that the lead's cumulative frequencies of all processes were conforming to lognormal distribution.