Reaction Mechanism and Technical Application of Metallic Bismuth Extraction from Bismuthinite Concentrate by Low-Temperature Alkaline Smelting

Abstract

Traditional bismuthinite concentrate precipitation smelting has problems of low recovery of valuable metals (e.g., Bi, Cu, Mo, and Ag), high fuel consumption, and high cost of SO 2 flue gas treatment. Therefore, in this study, an eco-friendly alkaline smelting process was proposed to extract metallic bismuth and recover valuable metals. The phase equilibrium composition of the Bi 2 S 3 -Na 2 CO 3 -C system was revealed by thermodynamic simulations at different temperatures and reductant contents. Based on reaction product characterizations and thermodynamic simulations, the following reaction mechanism and suitable bismuth extraction path were confirmed: Bi 2 S 3 first reacted with Na 2 CO 3 to form Bi 2 O 3 and Na 2 S, and the intermediate (Bi 2 O 3 ) was then reduced to metallic Bi by both C and CO. Under optimized conditions (W bismuthinite /W Na2CO3 /W coke = 200:300:20, 900 °C, 150 min), up to 96.56% Bi, 75.07% Pb, and 85.11% Ag were enriched in crude bismuth, respectively, while 93.57% Cu, 70.23% Fe, 96.63% Mo, and 94.34% W entered the salt slag. More than 99.9% W and Mo were recovered as Na 2 WO 4 and Na 2 MoO 4 , respectively, from the salt slag by water leaching. In the leaching residue, chalcopyrite, pyrite, and elemental sulfur could be recovered by flotation.

Green Extraction of Metallic Bismuth from Bismuth Sulfide Concentrate via Reductive Sulfur-Fixed Smelting

“…According to previous research, , for reaction , Bi 2 S 3 first reacted with Fe 2 O 3 to form Bi, Fe 3 O 4 , FeS, and SO 2 (reaction ), and then SO 2 was absorbed by Na 2 CO 3 to form Na 2 SO 4 (reaction). Bi 2 normalS 3 + 18 Fe 2 O 3 = 2 Bi + 12 Fe 3 O 4 + 3 SO 2 false( normalg false) normalΔ G T θ = prefix− 0.909 T + 507.18 Na 2 CO 3 + SO 2 false( normalg false) = 0.75 Na 2 SO 4 + 0.25 Na 2 normalS + CO 2 false( normalg false) normalΔ G T θ = 0.101 T − 359.60 …”

“…According to previous research, 28,31 for reaction 3, Bi 2 S 3 first reacted with Fe 2 O 3 to form Bi, Fe 3 O 4 , FeS, and SO 2 (reaction 4), and then SO 2 was absorbed by Na 2 CO 3 to form Na 2 SO 4 (reaction5). (5)…”

Utilization of Flotation Wastewater for Separation of Chalcopyrite and Molybdenite by Selective Surface Passivation

“…In nature, a considerable part of tungsten ore is accompanied by copper-molybdenum ore, forming a Cu-Mo-W polymetallic ore, and in most cases, they exist in the form of scheelite (CaWO 4 ), chalcopyrite (CuFeS 2 ), and molybdenite (MoS 2 ), respectively [9][10][11]. Usually, Cu-Mo bulk flotation concentrate is obtained first, then it is separated into chalcopyrite concentrate and molybdenite concentrate [12], and finally scheelite is recovered from the tailings of Cu-Mo bulk flotation [13,14].…”