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Zinc Smelting. What role did it play in the Donora disaster?. Zinc Ore. Main Component. Zinc sulfate ( ZnS ) is the main component of zinc ore. The Zinc Smelting Process. Two Smelting Processes Hydrometallurgic & Pyrometallurgic.
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Zinc Smelting What role did it play in the Donora disaster?
Main Component Zinc sulfate (ZnS) is the main component of zinc ore
Two Smelting ProcessesHydrometallurgic & Pyrometallurgic Contrast the two zinc refining processes (2 differences) Which process would be used to smelt zinc ore with lots of lead? Which process is the most used globally?
Step 1: Roasting __ ZnS + __ O2 __ ZnO + __ S CaF2 + H2SO4 → CaSO4 + 2 HF What type of reaction is this? (See the choices above)
Step 1: Roasting Byproducts • Where does the sulphur go? • Sulphur combines with oxygen forming sulphur dioxide which is then converted sulfur trioxide and finally to sulphuric acid. • S + O2 > SO2 • 2 SO2 + O2 > 2 SO3 • H2O + SO3 > H2SO4 Type of reaction:
Step 1: Roasting Byproducts • Important note: During this step, other “waste” compounds are broken down releasing various harmful gases. • Example: Fluorspar (CaF2) reacts with sulphuric acid forming calcium sulfate and hydrogen fluoride gas. • CaF2 + H2SO4 > CaSO4 + 2 HF Type of reaction:
Step 2: Leaching • Sulphuricacid is added to dissolve zinc oxide forming zinc sulphate and water. • Write the chemical equation for this reaction. • Prove that it is balanced.
Activity of Metals Circle the MORE reactive element in each pair. Pair 1: PbLi Pair 2: Ca Ni Pair 3: Mg Mn
Step 3: Purification Powdered zinc (Zn) is added to the zinc sulphate solution. The zinc (Zn) reacts with copper sulphate (CuSO4) – one of the impurities. Predict how zinc will react based on the activity chart. Write the correct equation here. Identify the type of reaction:
Step 4: Electrolysis Circle the zinc product. 2 ZnSO4 + 2 H2O > 2 H2SO4 + 2 Zn + O2
Step 2: Sintering • The zinc oxide is sintered where carbon in combustion gases reacts with impurities such as lead oxide, cadmium oxide and fluorine… • CO2 + PbO > PbCO3 • CO2 + CdO > CdCO3 • CO2 + 4F > CF4 + O2
Step 3: Retorting • Balance this equation. • __ C + __ O2 > __ CO • Fill in the missing compounds. • ZnO + ____ > Zn (vapor) + ____