TY - JOUR
T1 - Production of pure tungsten oxide from scheelite concentrates
AU - Gürmen, Sebahattin
AU - Timur, Servet
AU - Arslan, Cüneyt
AU - Duman, Ismail
PY - 2002/6
Y1 - 2002/6
N2 - Scheelite concentrates, obtained from Uludag, Bursa (Turkey), containing roughly 50% W, are treated by the chelate-added acidic leaching route. Dissolved tungsten runs are then selectively precipitated by the addition of 'ammonia ion-containing' reagents - either organic or inorganic - and thus are purified from other ions present in the solution. Selective precipitation of pure (>99%) tungstate salt was realized from the polytungstate solution at 25°C by adding a 'chelate-breaking agent' at a NH4+/WO3 weight ratio of ≥ 1/4. The formula of the complex salt is indicated by (NH4)3PW12O40·9H2O . The optimum precipitation conditions are investigated with the aim of making pure tungsten oxide via a thermal breakdown process. Tri-ammonium-dodeka-tungstate-phosphate salt can be easily converted to nanometer-sized WO3 particles by a simple calcination operation carried out above 650°C. Weight loss ratios of the samples vary between 8.7 and 9.6% at the end of this 2-h thermal breakdown process. Tungsten trioxide obtained can be suitably employed in tungsten-related powder metallurgy applications with its extremely low impurity content of 0.04% Mo, 0.15% SiO2, 0.06% Fe and 0.03% Al.
AB - Scheelite concentrates, obtained from Uludag, Bursa (Turkey), containing roughly 50% W, are treated by the chelate-added acidic leaching route. Dissolved tungsten runs are then selectively precipitated by the addition of 'ammonia ion-containing' reagents - either organic or inorganic - and thus are purified from other ions present in the solution. Selective precipitation of pure (>99%) tungstate salt was realized from the polytungstate solution at 25°C by adding a 'chelate-breaking agent' at a NH4+/WO3 weight ratio of ≥ 1/4. The formula of the complex salt is indicated by (NH4)3PW12O40·9H2O . The optimum precipitation conditions are investigated with the aim of making pure tungsten oxide via a thermal breakdown process. Tri-ammonium-dodeka-tungstate-phosphate salt can be easily converted to nanometer-sized WO3 particles by a simple calcination operation carried out above 650°C. Weight loss ratios of the samples vary between 8.7 and 9.6% at the end of this 2-h thermal breakdown process. Tungsten trioxide obtained can be suitably employed in tungsten-related powder metallurgy applications with its extremely low impurity content of 0.04% Mo, 0.15% SiO2, 0.06% Fe and 0.03% Al.
KW - Acidic leaching
KW - Chelate-added acidic leaching
KW - Hydrometallurgy
KW - Scheelite concentrate
KW - Tungsten
UR - http://www.scopus.com/inward/record.url?scp=0036610145&partnerID=8YFLogxK
U2 - 10.1034/j.1600-0692.2002.310309.x
DO - 10.1034/j.1600-0692.2002.310309.x
M3 - Article
AN - SCOPUS:0036610145
SN - 0371-0459
VL - 31
SP - 221
EP - 228
JO - Scandinavian Journal of Metallurgy
JF - Scandinavian Journal of Metallurgy
IS - 3
ER -