Hindustan Zinc Limited

Published on Tuesday, February 13, 2018 by Chittorgarh.com Team | Modified on Monday, July 22, 2019

Hindustan Zinc Limited (HZL) was incorporated in January, 1966 as a public sector company, after the takeover of the erstwhile Metal Corporation of India Limited, to develop mining and smelting capacities and to substantially meet the domestic demand of zinc and lead metals.

Hindustan Zinc Limited is a Vedanta Group Company in Zinc, Silver and Lead business which is one of the world's largest integrated producers of zinc and are among leading global lead and silver producers. It is one of the lowest cost producers in the world and are well placed to serve the growing demand of Asian countries.Hindustan Zinc is a subsidiary of the BSE and NSE listed Vedanta Limited (ADRs listed on the NYSE which was earlier known as Sesa Sterlite Limited), a part of London listed diversified metals and mining major, Vedanta Resources plc.

The core business comprises of mining and smelting of zinc and lead along with captive power generation. They have a metal production capacity of over one million tonnes per annum with the key lead-zinc mines in Rampura Agucha and Sindesar Khurd; and key modern smelting complexes in Chanderiya and Dariba, all in the state of Rajasthan in India. With 404.4 million tonnes of reserves and resources, their exploration programme is integral to our growth and future expansions.

Hindustan Zinc Smelter, Chanderiya, Chittorgarh

Chanderiya Lead-Zinc Smelter is the one of the largest zinc-lead smelting complexes in the world. Its current metal production capacity is 610,000 tonnes per annum which is 525,000 tonnes per annum of zinc and 85,000 tonnes per annum of lead. In the end of March 2017, Chanderiya produced 435,666 MT of zinc and 51,759 MT of lead. The main products are special high grade (SHG) zinc, continuous galvanizing grade (CGG) zinc, prime western (PW) zinc and pure lead and it also produces a number of valuable by-products including silver.

Chanderiya is located 110 Kms North of Udaipur in the State of Rajasthan, India. With an initial production capacity of 70,000 MT per annum of zinc and 35,000 MT per annum of lead, it was commissioned in the year 1991. In the past 6 years, the capacity of the plant has been expanded five folds to its current capacity of 525,000 MT per annum of zinc and 85,000 MT per annum of lead.

Chanderiya Lead-Zinc Smelting complex comprises of one lead-zinc Pyrometallurgical smelter (35,000 MT lead and 105,000 MT zinc), one Ausmelt lead smelter (50,000 MT) and two Hydro metallurgical zinc smelters (Hydro I & Hydro II of 210,000 MT each). It employs Roast Leach Electro-winning Technology in its Hydro metallurgical smelters, Imperial Smelting Process in lead-zinc smelter, and Top Submerged Lance Technology (Designed by M/S Ausmelt Ltd., Australia) coupled with Cansolv Technology for its lead smelter. The complex also has 234 MW (77 + 77 + 80 MW) of captive thermal power capacity to supply the power requirements for its metallurgical operations and it also has 14.81 MW of DG set and 13.7 MW (9.4 MW+4.3 MW) of power generation capacity through waste heat recovery.

Process Desription:

• Roast Leach Electro-winning (RLE):
  The hydrometallurgical smelting process is a roast, leach and electro-winning process. In this process, zinc concentrate is first oxidized in the roaster and the gases generated are cleaned and sent to the sulphuric acid plant. The primary output from the roaster is called calcine, which is sent to the leaching plant to produce a zinc sulphate solution that is then passed through a cold/hot purification process to produce purified zinc sulphate solution. The purified zinc solution then goes through an electrolysis process to produce zinc cathodes and finally, the zinc cathodes are melted and cast into zinc ingots.
• Imperial Smelting Process (ISP):
  1. ZINC: The Pyrometallurgical smelter uses the Imperial Smelting Process (ISP), whose process starts with sintering, where lead and zinc concentrates, bulk concentrates ( a mixture of zinc and lead concentrates) are blended with secondaries and fluxes. The mixture is passed through the sinter machine to remove sulphur. The gas generated from the sintering process is sent to the sulphuric acid plant. The de-sulphurized output of the sinter machine is broken for size reduction before being fed into an Imperial Smelting Furnace, or ISF, where it is smelted with preheated met-coke and air.
  2. LEAD: There are two lead smelters, of which one is based on Pyrometallurgical ISP process and is part of the Pyrometallurgical lead-zinc smelter while the other is based on Top Submerged Lance Technology. The Pyrometallurgical process involves the smelting of lead and zinc together and Lead removed from the Pyrometallurgical process is sent for further refining where it passes through a series of processes to remove impurities. In this process, silver is also produced as a by-product and the refined lead is cast into lead ingots.