There are two major processes (lead chamber and contact) for production of sulphuric acid, and it is available commercially in a number of grades and concentrations. The lead chamber process, the older of the two processes, is used to produce much of the acid used to make fertilizers; it produces a relatively dilute acid (62%–78% H2SO4). The contact process produces a purer, more concentrated acid but requires purer raw materials and the use of expensive catalysts. In both processes sulphur dioxide is oxidized and dissolved in water. The sulphur dioxide is obtained by burning sulphur, by burning pyrites (iron sulphides), by roasting nonferrous sulphide ores preparatory to smelting, or by burning hydrogen sulphide gas. Some sulphuric acid is also made from ferrous sulphate waste solutions from pickling iron and steel and from waste acid sludge from oil refineries.

Cashew Nut Shell Liquid is considered as a cost effective modern material, in the search for the cost effective modern materials, CNSL and its products have a significant role to play. Being renewable, it offers much advantage over synthetics. Its versatility stems from its innumerable applications in many areas. Recent research has shown that the constituents of CNSL possess special structural features for transformation into specialty chemicals and high value polymers. This involves a value addition of many orders of magnitude and the chemical transformation provides 100% chemically pure products. Thus, CNSL offers vast scope and opportunities for the production of specialty chemicals, high value products and polymers.

The raw cashew nut has a shell of about 18 inch thickness inside which is a soft honeycomb structure containing a dark reddish brown viscous liquid. It is called the cashew nut shell liquid (CNSL), which is the pericarp fluid of the cashew nut. It is obtained by the process of roasting of raw cashew nut shell.

There are two major processes (lead chamber and contact) for production of sulphuric acid, and it is available commercially in a number of grades and concentrations. The lead chamber process, the older of the two processes, is used to produce much of the acid used to make fertilizers; it produces a relatively dilute acid (62%–78% H2SO4). The contact process produces a purer, more concentrated acid but requires purer raw materials and the use of expensive catalysts. In both processes sulphur dioxide is oxidized and dissolved in water. The sulphur dioxide is obtained by burning sulphur, by burning pyrites (iron sulphides), by roasting nonferrous sulphide ores preparatory to smelting, or by burning hydrogen sulphide gas. Some sulphuric acid is also made from ferrous sulphate waste solutions from pickling iron and steel and from waste acid sludge from oil refineries.

Cashew Nut Shell Liquid is considered as a cost effective modern material, in the search for the cost effective modern materials, CNSL and its products have a significant role to play. Being renewable, it offers much advantage over synthetics. Its versatility stems from its innumerable applications in many areas. Recent research has shown that the constituents of CNSL possess special structural features for transformation into specialty chemicals and high value polymers. This involves a value addition of many orders of magnitude and the chemical transformation provides 100% chemically pure products. Thus, CNSL offers vast scope and opportunities for the production of specialty chemicals, high value products and polymers.

The raw cashew nut has a shell of about 18 inch thickness inside which is a soft honeycomb structure containing a dark reddish brown viscous liquid. It is called the cashew nut shell liquid (CNSL), which is the pericarp fluid of the cashew nut. It is obtained by the process of roasting of raw cashew nut shell.