Maarg Manthan · Topic 2.4

Non-Metallic Minerals (Sulphur, Phosphates, Cement Minerals)

Geography › Geology – Minerals and Rocks · Topic 2.4

Non-metallic minerals do not yield metals when processed. They include sulphur, phosphates and the minerals used in cement, such as limestone, gypsum and clay, as well as mica, salt, graphite and building stones. Sulphur is found as a native element near volcanoes and in salt domes, and is used to make sulphuric acid. Phosphates, from phosphorite and apatite, are the raw material of phosphatic fertilisers. Limestone, gypsum and clay are the main raw materials for cement.

5 min read · UPSC Prelims · Geography · Geology – Minerals and Rocks

At a Glance

Sulphur Volcanic regions, salt domes; for sulphuric acid
Phosphates Phosphorite and apatite; for fertilisers
Cement minerals Limestone, gypsum and clay
Largest phosphate reserves Morocco and Western Sahara
Gypsum in India Mainly Rajasthan
Exam link UPSC Prelims, Geography: Geology – Minerals and Rocks

Where Does It Fit?

This topic follows the one on metallic minerals and covers the other major class, the non-metallic minerals. Together the two topics describe the mineral wealth that is used in industry, agriculture and construction. Previous topic: chromite, nickel, cobalt, tungsten Non-ferrous Copper, bauxite, lead, zinc, tin Precious Gold, silver, platinum Main iron…">Metallic Minerals (Precious, Ferrous, Non-Ferrous). Next topic: Rocks as Aggregates of Minerals; Petrology.

What Are Non-Metallic Minerals?

In short: non-metallic minerals are useful for what they are, not for the metal in them.

Fuel minerals: coal, petroleum and natural gas, which are organic in origin, are called mineral fuels.
Chemical and fertiliser minerals: sulphur, phosphates, potash and nitrates.
Industrial and building minerals: limestone, gypsum, clay, mica, asbestos, graphite, salt, sand and building stones such as granite and marble.
Gemstones: diamond, ruby, emerald and others.

They are mined mostly from sedimentary rocks, so their distribution differs from the metallic minerals of old shields. They are often bulky and cheap, so they are mined near the place of use. Many are mined by open-cast methods. Because they are needed for roads, buildings and farms, their output rises with a country’s growth, and their mining has to be managed to limit dust, loss of soil and damage to groundwater.

What Is Sulphur and How Is It Obtained?

Sulphur is a yellow, brittle non-metallic element that occurs as a native element in several settings.

Volcanic deposits: sulphur crystallises around volcanic vents and hot springs, as in Italy (Sicily), Japan and Indonesia.
Salt dome deposits: sulphur is pumped as molten liquid by the Frasch process, where superheated water is forced down a well, as in the Gulf coast of the United States.
Sulphide minerals: pyrite and other sulphides yield sulphur on roasting.
By-product: today most sulphur comes from cleaning sulphur out of crude oil and natural gas.

Sulphur dioxide from burning sulphur-rich fuels also causes acid rain, which is why sulphur is removed from fuels. The main use of sulphur is to make sulphuric acid for fertilisers, chemicals, batteries and oil refining. It is also used in matches, gunpowder, rubber vulcanisation and insecticides. India has little native sulphur and gets it from refineries and by import.

What Are Phosphates?

Phosphate rock is the source of phosphorus, which is a key nutrient for plants. The commercial ores are phosphorite, which forms in sedimentary basins from marine deposits, and apatite, which is found in igneous rocks.

Aspect	Details
Uses	Phosphatic fertilisers such as single superphosphate and DAP, animal feed, detergents and chemicals
World reserves	Morocco and Western Sahara hold the largest reserves; China, the United States, Russia and Jordan are other important producers
India	Rajasthan (Jhamarkotra near Udaipur), Madhya Pradesh and Uttar Pradesh (Lalitpur); India imports much phosphate rock and fertiliser
Concern	Phosphate is a finite resource, and runoff of phosphate causes eutrophication in lakes and rivers

Which Minerals Are Used to Make Cement?

Cement is a binding powder made by heating limestone and clay to a very high temperature, then grinding the product with a little gypsum.

Mineral	Role in cement	Main areas in India
Limestone	Main raw material, about 85 to 90 per cent of the mix	Rajasthan, Madhya Pradesh, Andhra Pradesh, Telangana, Karnataka, Gujarat, Chhattisgarh
Clay or shale	Gives silica, alumina and iron	Found near limestone
Gypsum	Slows the setting of cement	Rajasthan (the main producer), with some in Tamil Nadu and Jammu and Kashmir
Coal or petroleum coke	Fuel for the kiln	Mines and imports

Limestone is a sedimentary rock made of the mineral calcite, as explained in Three Families of Rocks: Igneous, Sedimentary, Metamorphic. As an analytical point, cement plants are sited close to limestone because the rock is bulky, and the same limestone belts support steel and fertiliser industries. The metallic side of mineral wealth is in Metallic Minerals (Precious, Ferrous, Non-Ferrous).

Why Is This Topic Important?

Uses Fertilisers and cement
Areas State-wise producers are asked
Concern Eutrophication and limits

What Came Next?

The next topic moves from minerals to rocks, which are aggregates of minerals, and to the science of petrology. Next topic: Rocks as Aggregates of Minerals; Petrology.

Key People and Terms

Native sulphur Sulphur found as a pure element
Frasch process Extracting sulphur by hot water
Phosphorite Sedimentary phosphate rock
Apatite Igneous phosphate mineral
Gypsum Hydrated calcium sulphate
Portland cement Common type of cement

Exam Corner

Points to Remember

Sulphur is used mainly to make sulphuric acid.
Morocco has the largest phosphate reserves.
Gypsum is added to cement to slow setting.
Gypsum in India is mainly from Rajasthan.
Phosphate runoff causes eutrophication.

Do Not Confuse With

Phosphorite and apatite Sedimentary rock versus igneous mineral
Limestone and gypsum in cement Main raw material versus a setting regulator
Native sulphur and pyrite The element versus a sulphide ore

Memory Hook

Sulphur for acid, phosphate for the field; limestone, clay and gypsum make cement’s yield.

Mains Angle

Questions link these minerals to agriculture and construction. These points add depth.

Agriculture Fertiliser raw materials
Construction Cement and limestone belts
Environment Nutrient pollution

A Question You May Face

An original practice question, not a past paper question.

“Discuss the importance of non-metallic minerals such as phosphates and the cement minerals for the Indian economy.”

How to Answer

Define Non-metallic minerals.
Phosphates Fertilisers and imports.
Cement Limestone and gypsum belts.
Issues Dependence and pollution.

GS Relevance

Prelims: sulphur, phosphate and cement minerals with their uses and areas. GS Paper 1: distribution of key natural resources.

Frequently Asked Questions

What are non-metallic minerals?

Non-metallic minerals are those that do not yield metals when processed. They include mineral fuels, fertiliser minerals such as phosphates and sulphur, and industrial minerals such as limestone, gypsum, mica, salt and graphite. They are mostly found in sedimentary rocks and used in industry, farming and construction.

What is sulphur used for?

Sulphur is used mainly to make sulphuric acid, which is the most widely used industrial chemical, in fertilisers, batteries, oil refining and chemicals. It is also used in matches, gunpowder, vulcanising rubber and insecticides. Most sulphur is now recovered as a by-product from oil and natural gas.

Which country has the largest reserves of phosphate?

Morocco, including Western Sahara, holds the largest reserves of phosphate rock in the world, followed by countries such as China, Egypt and Algeria. In India, phosphate is found in Rajasthan, Madhya Pradesh and Uttar Pradesh, and the country imports a large share of its needs.

Which minerals are used in making cement?

Cement is made mainly from limestone, which forms about 85 to 90 per cent of the raw mix, along with clay or shale for silica and alumina. Gypsum is ground in at the end to slow the setting of the cement, and coal or petroleum coke is used as fuel.

Which Indian state is the main producer of gypsum?

Rajasthan is by far the main producer of gypsum in India, with deposits in Bikaner, Nagaur, Jaisalmer and other districts. Gypsum is used in cement, in plaster and as a soil conditioner in farming. Smaller amounts are mined in Tamil Nadu and Jammu and Kashmir.

PYQ Practice — Statement Analysis

1 Gypsum is added to cement to slow its setting.

True

It controls the setting time.

2 Sulphur is mainly used to make nitric acid.

False

It is used to make sulphuric acid.

3 Morocco holds the largest reserves of phosphate rock.