2. Tungsten is commonly produced from wolframite ores consisting of 6% FeW04, 4.7% MnW04, 1.01 % CaWO4 and inert impurities. The following steps are employed: FLOTATION: This separates the ore into a concentrate containing the entire tungsten compound with a purity of 90% on a. dry basis. 97% of the water in the flotation cell goes with the tailings and the rest with the concentrate. The concentrate carries 3% of its dry weight as water. DIGESTION: Treatment with aqueous (40% NaOH) boiling caustic forms the soluble sodium tungstate, NazW04, ferrous, manganous and calcium hydroxide and 3 wt% dissolved impurities. The reactions taking place in the digester are as follows: FeWO4 + NAOH → Fe(OH)2 + NazWO4 MNWO4 + NaOH Mn(OH)2 + NazWO4 CaWO4 + NaOH Ca(OH)2 + NazWO4 PURIFICATION: Contact with 20% excess NH40H yields 99.97% Ammonium paratungstate, 5(NH4)20.12W03.5H20. Reaction with the nitric gives tungstic acid, H2W04, which is converted to the oxide WO3 by roasting at 1000°C. Consider the following reactions: NazWO4 + NH3 + H20 → 5(NH4)20.12W03.5H20 + NAOH 5(NH4)20.12W03.5H20 + HNO3 + H20 H2WO4 + H2WO4 + NH4NO3 O2 → WO3 + H20 + 02 REDUCTION: Countercurrent reduction with H2 at 800°C yields impure tungsten powder. WO3 + H2 → W + H2O On a basis of 2000 kg of ore, make a complete material balance for the system. MNWO4 = 302.78 MW: FeWO4 = 303.69 CaWO4 = 278.84 NaOH = 40 Ca(OH)2 = 74 H2WO4 = 249.84 NazWO4 = 293.84 Fe(OH)2 = 84.85 5(NH4)20.12W03.5H20 = 3132.2 Mn(OH)2 = 88.94 HNO3 = 63 WO3 = 231.84 W = 183.84
2. Tungsten is commonly produced from wolframite ores consisting of 6% FeW04, 4.7% MnW04, 1.01 % CaWO4 and inert impurities. The following steps are employed: FLOTATION: This separates the ore into a concentrate containing the entire tungsten compound with a purity of 90% on a. dry basis. 97% of the water in the flotation cell goes with the tailings and the rest with the concentrate. The concentrate carries 3% of its dry weight as water. DIGESTION: Treatment with aqueous (40% NaOH) boiling caustic forms the soluble sodium tungstate, NazW04, ferrous, manganous and calcium hydroxide and 3 wt% dissolved impurities. The reactions taking place in the digester are as follows: FeWO4 + NAOH → Fe(OH)2 + NazWO4 MNWO4 + NaOH Mn(OH)2 + NazWO4 CaWO4 + NaOH Ca(OH)2 + NazWO4 PURIFICATION: Contact with 20% excess NH40H yields 99.97% Ammonium paratungstate, 5(NH4)20.12W03.5H20. Reaction with the nitric gives tungstic acid, H2W04, which is converted to the oxide WO3 by roasting at 1000°C. Consider the following reactions: NazWO4 + NH3 + H20 → 5(NH4)20.12W03.5H20 + NAOH 5(NH4)20.12W03.5H20 + HNO3 + H20 H2WO4 + H2WO4 + NH4NO3 O2 → WO3 + H20 + 02 REDUCTION: Countercurrent reduction with H2 at 800°C yields impure tungsten powder. WO3 + H2 → W + H2O On a basis of 2000 kg of ore, make a complete material balance for the system. MNWO4 = 302.78 MW: FeWO4 = 303.69 CaWO4 = 278.84 NaOH = 40 Ca(OH)2 = 74 H2WO4 = 249.84 NazWO4 = 293.84 Fe(OH)2 = 84.85 5(NH4)20.12W03.5H20 = 3132.2 Mn(OH)2 = 88.94 HNO3 = 63 WO3 = 231.84 W = 183.84
Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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Can you please include the diagram for more visualization thank you
Transcribed Image Text:2. Tungsten is commonly produced from wolframite ores consisting of 6% FeW04, 4.7% MnW04, 1.01 % CaW04 and
inert impurities. The following steps are employed:
FLOTATION: This separates the ore into a concentrate containing the entire tungsten compound with a purity of
90% on a. dry basis. 97% of the water in the flotation cell goes with the tailings and the rest with the concentrate.
The concentrate carries 3% of its dry weight as water.
DIGESTION: Treatment with aqueous (40% NaOH) boiling caustic forms the soluble sodium tungstate, NazW04,
ferrous, manganous and calcium hydroxide and 3 wt% dissolved impurities. The reactions taking place in the
digester are as follows:
FeWO4 + NaOH → Fe(OH)2 + NA2WO4
MNWO4 + NaOH → Mn(OH)2 + NazWO4
CaWO4 + NaOH → Ca(OH)2 + NazWO4
PURIFICATION: Contact with 20% excess NH40H yields 99.97% Ammonium paratungstate, 5(NH4)20.12W03.5H20.
Reaction with the nitric gives tungstic acid, H2W04, which is converted to the oxide WO3 by roasting at 1000°C.
Consider the following reactions:
NazWO4 +
NH3 +
H20 → 5(NH4)20.12W03.5H20 + NAOH
5(NH4)20.12W03.5H20 + HNO3 + H20 → H2WO4 +
H2WO4 + O2 → WO3
NH4NO3
+ H20 + 02
REDUCTION: Countercurrent reduction with H2 at 800°C yields impure tungsten powder.
WO3 + Hz → W + H20
On a basis of 2000 kg of ore, make a complete material balance for the system.
MW:
FeWO4 = 303.69
MNWO4 = 302.78
CaWO4 = 278.84
NaOH = 40
%3D
%3D
%3D
Fe(OH)2 = 84.85
5(NH4)20.12W03.5H20 = 3132.2
Mn(OH)2 = 88.94
Ca(OH)2 = 74
H2WO4 = 249.84
N22WO4 = 293.84
WO3 = 231.84
%3D
%3D
%3D
HNO3 = 63
W = 183.84
%3D
%3D
%3D
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