Faiza Tehseen

Despite having large deposits of limestone, the raw material used to produce quicklime, Pakistan spends a handsome foreign exchange on its import.

"This sitiation is not only harming the mining sector but also increasing the production cost of the home industry,” said Abdul Bashir, chief geologist with Koh-e-Daleel Mining Company Private Limited. Talking to WealthPK, he said quicklime is an important material used to serve a variety of industrial and domestic purposes. “Turning limestone into quicklime is not a complicated or expensive process.

This value-added form of limestone is profit-oriented and can be made an export commodity as well. For this purpose, processing units can be established near the mining areas.” Talking about the formation and occurance of limestone in Pakistan, he said it is mainly a sedimentary rock formed by the accumulation of organic and inorganic materials over time.

Bashir said it abundantly occured across Pakistan at different places – upper Indus basin, lower Indus basin, Nari formation limestone in Jamshoro district, Peshawar basin, Attock-Cherat range, Karakoram, Balochistan, Axial belt, Khyber, Kohistan Island Arc, Hazara basin, salt range, Rawalpindi, Attock, Chakwal, Jhelum, Khushab, Mianwali, and Gaj formation limestone in Mattar area.

Discussing with WealthPK the importance of limestone production locally, Dr Riffat Tahira, a scientist from National Agricultural Research Centre, said: “Crushed lime (calcium carbonate) is heated at high temperatures (around 900ᵒC to 1,000⁰C) in a kiln. This process is called calcination. In this heating process, the crushed lime rock decomposes, carbon dioxide gas is derived off it and quicklime (calcium oxide) remains behind as a final product.”

She said that at room temperature, quicklime is a white, alkaline, caustic, crystalline solid. “It is an important chemical compound that is used for different industrial, environmental and domestic purposes. “Quicklime is also known with different other names – burnt, calcined, handpicked, lump, caustic, and fluxing lime.”

“Establishing quicklime processing plants will be a good addition to domestic industry, leading to value-addition, job creation and sustainable livelihoods,” Tahira said.   Because of its reactivity, low melting point, and high heat capacity, quicklime serves many industrial purposes, including flue gas desulfurisation; production of iron, steel, paper, and pulp; chemical manufacturing, making water detection paste, as a flux in glass and porcelain production, and in the construction sector.

Quicklime is used to improve drinking water quality by increasing its pH and alkalinity, softening it by removing solids and impurities, neutralising acidity, and eliminating the cloudiness. It is also used to treat wastewater and sludge. In the pharmaceutical sector, it is a great source to obtain calcium, and is used as an important ingredient in toothpaste, dietary supplements, and antacids. In environmental remediation processes, quicklime plays a key role.

It neutralises acidic substances, precipitates the heavy metals, adjusts soil pH levels, and stabilises the contaminated soil. For agricultural and horticultural purposes, it helps in soil stabilisation, fertility, and improving soil quality for better plant growth. Global quicklime market is anticipated to grow to $9.70 billion at a compound annual growth rate of 4.49% by the year 2034 from $6.25 billion in 2024.

Credit: INP-WealthPk