The changing dynamics of the gas-dust flow in the flash smelter due to addition of a spoiler. Part 2. Pilot tests

Abstract

The use of man-made deposits and fine ore concentrates in the flash smelter process, as well as the poorer quality of the raw materials observed (due to a higher share of particles smaller than 10 μm) lead to a higher amount of entrained dust and causes accretion in the slag end, uptake shaft and waste heat boiler. A higher dust entrainment is associated with a higher recycle, lower energy capacity of the raw materials and poorer recovery of non-ferrous metals. Numeric modelling of the heat and mass exchange processes in the gas environment of the settler and uptake shaft helped determine how different sizes and locations of the spoiler can change the gas flow parameters of the flash smelter. The modelling study showed that a 500 mm wide (the width of the settler) and 270 mm high spoiler mounted on the fire side of the settler at least 2,000 mm away from the entry to the uptake shaft could help reduce the amount of entrained dust by as much as 20% (relative) depending on the size and density of gas-dust particles. On the basis of the above calculations, a series of pilot tests was conducted on Line 1 of Nadezhda Metallurgical Plant in July 2019. Using various analysis techniques (such as thermal imaging of the surface in the spoiler area, the gas temperature, the gas flow rate, as well as methods used in analytical chemistry, scanning electron microscopy and X-ray spectral microanalysis), the authors of this paper examined the effect produced by the mounted spoiler on the gas flow. The authors would like to thank the leadership and the operations personnel of Nadezhda Metallurgical Plant for their support and great contribution to the pilot tests performed.