Nonmetal Minerals
Learning outcome:
- Definition of nonmetal minerals with an example
- Frasch method of sulfur extraction and its uses with the description of some of its compounds
- Contact method of sulfuric acid preparation and its property
Nonmetal Minerals
The nonmetals that are extracted from mines are called nonmetal minerals. Sulfur is a nonmetal mineral extracted from mines.
Frasch Method of Sulfur Extraction
Sulfur is a yellow coloured substance and its mines are situated deep inside the earth. Sulfur is extracted from mine by Frasch method.
Step- 1: Three tubes with a single center is inserted into the depth of the sulfur layer which is known as Frasch pipe.
Step- 2: Sulfur melts at 115°C temperature. Super-heated water enters through the pipe to the layer so that the element melts. We know, at 1 atm pressure, the boiling point of water is 100°C. But with an increase of the pressure, the boiling point also rises up. Thus water at any temperature between 100-374°C temperature in extra pressure is called super-heated water.
Frasch Method of Sulfur Extraction
Step- 3: Hot air is passed at 20-22 atm pressure through the center tube. Thus molten sulfur comes out through the middle tube due to the effect of the pressure. Finally, it is collected in the containers.
Use of Sulfur
Sulfur has different uses in different Industries.
i. Greatly used in the preparation of sulfuric acid
ii. Added to rubber to make rubber more sustainable. This method is called vulcanizing of rubber
iii. Sulfanide is used in the preparation of various kinds of medicines since it kills bacteria. It is produced from sulfur
Sulfur Compounds
Here, we will discuss some important sulfur compounds.
Sulfur Dioxide
Sulfur undergoes reaction with oxygen from air and produces sulfur dioxide. 
SO2 is a highly toxic gas with acute odour. It harms our body if it enters inside through our mouth and nose. It also creates a burning sensation in the eyes. Coal and petroleum contained sulfur burning produce SO2 gas. Then it goes into the air and during rain, it undergoes reaction with water and produces sulfurous acid (H2SO3). Then it comes back to earth with rainwater and this is acid rain. 
Sulfuric Acid
Of all the chemical, sulfuric acid is the highest used and so it is called the king of the chemicals.
The Contact Method of Sulfuric Acid Preparation
Sulfuric acid is prepared from solid sulfur in the industries and this method is called the contact method.
Preparation of Sulfuric Acid in Contact Method
Step 1: Sulfur and dehydrated air are supplied in a furnace. They undergo reaction here to produce sulfur dioxide (SO2). 
Step 2: The SO2 gas is channeled with some more oxygen to another furnace having the temperature of 450-500ºC and the catalyst vanadium pentaoxide. SO2 gas and O2 gas undergo reaction here in that temperature and produce sulfur tri-oxide (SO3).
Step 3: When SO3 comes in contact with H2O, they will produce H2SO4. However, direct reaction between them will produce gaseous H2SO4 which creates a state of dense fog. This is a hazard for the industries. Besides, getting liquid H2SO4 from this gaseous H2SO4 by condensation is really a tough task. Hence, first sulfur trioxide is absorbed in concentrated H2SO4 and that forms fuming sulfuric acid. (Fuming sulfuric acid is called oilium and its formula is H2S2O7). 
The fuming sulfuric acid is then driven into reaction with H2O which produces liquid sulfuric acid. 
The Properties of Sulfuric Acid
Acid Property
Dilute or concentrated H2SO4 undergoes reaction with any alkali to give salt and water. This is the acid property of sulfuric acid. Example, sulfuric acid reacts with calcium hydroxide to produce calcium sulfate salt and water.
Oxidation Property
If we add much water to H2SO4 solution then we get dilute sulfuric acid. It does not have oxidation property. But the concentrated sulfuric acid has oxidation property. It oxidizes copper to produce copper sulfate and reduces itself into sulfur dioxide and water. 
Dehydrating Property
Dehydrating agent is a substance that absorbs water from any compound. Chemical having this property is its dehydrating property. Dilute H2SO4 does not show any dehydrating property but the concentrated does. The concentrated H2SO4 absorbs water from sugar (C12H22O11). 
#Reference- NCTB Books
