What happens when iron pyrite is roasted?
The roasting of sulphide concentrates is often the first process step in the production of metals or chemicals. With the addition of air, iron sulphides are transformed into solid oxides and gaseous sulphur dioxide at temperatures of 600–1000°C.
Can you burn pyrite?
Pyrite doesn’t melt. When heated, it gives off part of its sulphur and turns into pyrrhotite. Further heating, with plenty of air, will cause it to burn, leaving iron oxide (“rust”).
What do I do with pyrite ore?
Pyrite used to be an important ore for the production of sulfur and sulfuric acid. Today most sulfur is obtained as a byproduct of oil and gas processing. Some sulfur continues to be produced from pyrite as a byproduct of gold production. Pyrite is occasionally used as a gemstone.
How do you oxidize pyrite?
The mechanism of pyrite oxidation may therefore be written as a series of steps:
- Preferrential release of ferrous ions to form a reacted sulfur layer (S)
- Hydrolysis of ferrous ions to form ferrous hydroxide.
- Oxidation of ferrous to ferric ions.
- Hydrolysis of ferric ions to ferric hydroxide.
Why roasting of FeS is done?
Roasting is a process of heating a sulfide ore to a high temperature in presence of air. It is a step of the processing of certain ores. More specifically, roasting is a metallurgical process involving gas–solid reactions at elevated temperatures with the goal of purifying the metal component(s).
What happens if you burn pyrite?
When coal containing pyrite is burned, sulfur dioxide is formed. Sulfur dioxide mixes with water molecules in the air, producing acid rain.
How long does it take for pyrite to oxidize?
Pyrite oxidation can be considered as the most important water–sediment reaction. Using kinetic methods, this reaction proved to be relatively a slow process, as the oxidation of pyrite takes ∼10–100 days to deplete O2 and NO3 into the water phase.
What happens when pyrite is mixed with water?
Sulfate released from decomposing pyrite combines with water, producing sulfuric acid, leading to acid mine drainage. An example of acid rock drainage caused by pyrite is the 2015 Gold King Mine waste water spill.
What is the source of energy for sulphide roasting?
Oxidizing roasting, the most commonly practiced roasting process, involves heating the ore in excess of air or oxygen, to burn out or replace the impurity element, generally sulfur, partly or completely by oxygen. For sulfide roasting, the general reaction can be given by: 2MS (s) + 3O2 (g) -> 2MO (s) + 2SO2 (g)
What happens to pyrite when it is roasted?
With the addition of air, the pyrite concentrates are transformed into solid oxides and gaseous sulphur dioxide at temperatures of 600–1000°C. After cleaning and cooling, the sulphur dioxide in the roasting gas is further processed to sulphuric acid.
What kind of gas is used to roast pyritic ore?
The roasting of straight pyritic ores involves the conversion of the iron sulphides to the oxide under oxidizing conditions with the evolution of sulphur dioxide and, to some extent by catalytic action, sulphur trioxide gas also.
How are pyrite concentrates transformed into sulphuric acid?
With the addition of air, the pyrite concentrates are transformed into solid oxides and gaseous sulphur dioxide at temperatures of 600–1000°C. After cleaning and cooling, the sulphur dioxide in the roasting gas is further processed to sulphuric acid. Two types of reactors are used depending on the application: stationary or circulating fluid bed.
What happens to an ore concentrate during roasting?
In roasting, the ore or ore concentrate is treated with very hot air. This process is generally applied to sulfide minerals. During roasting, the sulfide is converted to an oxide, and sulfur is released as sulfur dioxide, a gas. For the ores Cu 2 S ( chalcocite) and ZnS ( sphalerite ), balanced equations for the roasting are: