Zinc SmeltingWhat role did it play in the

Donora disaster?

Zinc Ore

Main ComponentZinc sulfate (ZnS) is the main

component of zinc ore

The Zinc Smelting Process

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 ByproductsWhere 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 ByproductsImportant 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:

Hydrometallurgic Process

Step 2: LeachingSulphuric acid 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 MetalsCircle the MORE reactive element in each pair.

Pair 1: Pb Li

Pair 2: Ca Ni

Pair 3: Mg Mn

Li

Most Reactive

Least Reactive

RbK

BaSrCaNaMgAl

MnZnCrFeCdCoNiSnPbH2

SbBiCuHgAgPt

Au

Step 3: PurificationPowdered 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:

Li

Most Reactive

Least Reactive

RbK

BaSrCaNaMgAl

MnZnCrFeCdCoNiSnPbH2

SbBiCuHgAgPt

Au

Step 4: Electrolysis

Circle the zinc product.2 ZnSO4 + 2 H2O > 2 H2SO4 + 2 Zn + O2

Pyrometallurgic Process

Step 2: SinteringThe 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: RetortingBalance this equation. __ C + __ O2 > __ CO

Fill in the missing compounds. ZnO + ____ > Zn (vapor) + ____