Dariba Smelting Complex
Overview
This complex stands out for its self-sufficiency, benefitting from nearby lead-zinc mines at Sindesar Khurd and Rajpura Dariba. With a capacity of 240,000 MT for zinc and 120,000 MT for lead, it achieved 234,000 MT of zinc and 112,000 MT of lead in the fiscal year ending March 2023. A significant portion of the facility’s power needs is met by the coal-based captive power plant in Dariba. The Dariba Smelting Complex employs Roast Leach Electro-winning technology in its hydrometallurgical zinc smelter, featuring two roasting facilities, a leaching and purification section, and a cell house.
The lead smelter employs SKS bottom blowing technology. The plant consists of SKS Furnace – bottom blowing, blast furnace, electric arc furnace & fuming furnace, and electro – refining. Furthermore, a fuming furnace is installed to produce zinc Oxide from blast furnace slag.
Key Facts
- Location : Rajsamand Rajasthan, India
- Technology : Roast Leach Electro-winning Technology, SKS Smelt Reduction Electro-Refining
- Products : Special High Grade (HG) zinc, lead
- Zinc Product Capacity: 250,000 MT per annum
- Lead Product Capacity : 120,000 MT per annum
- Certifications : LME grade Zn and Pb, ISO 9001 Certified
Background Information
Located in the Rajsamand district of Rajasthan in Northwest India, the zinc smelter at Dariba was commissioned in March 2010 and notably, in July 2011, a 100,000 MT per annum lead smelter was set up.
Process Description
Roast Leach Electro-Winning (RLE):
The hydrometallurgical smelting process involves roasting, leaching, and electro-winning (RLE). In this process, zinc concentrate undergoes oxidation in the roaster, with resulting gases cleaned and directed to the sulphuric acid plant. Oxygen enrichment has been done in roasters to increase roaster throughput which resulting in extra calcine production. The primary roaster output, calcine, is processed in the leaching plant, producing a zinc sulphate solution. This solution then undergoes cold/hot purification, yielding purified zinc sulphate solution. An electrolysis process transforms the purified solution into zinc cathodes. These cathodes are subsequently melted and cast into zinc ingots. Waste known as Jarofix is securely disposed of in a designated landfill.
SKS – Smelt Reduction Electro-Refining:
The SKS furnace employs a bottom-blowing process with oxygen to smelt lead concentrate, resulting in bullion production. Generated smelting gases are cleansed and directed to the sulphuric acid plant. The SKS furnace slag is subsequently reduced in a blast furnace to create additional bullion. Both SKS furnace and blast furnace bullion are being melted and converted into anodes for electro-refining, yielding lead cathodes. These cathodes are eventually melted and cast into lead ingots.
To make integrated unit of FG production at Dariba we have shifted melting casting (ICM) from PMP unit to Dariba unit. The slag from the blast furnace undergoes further processing to yield zinc oxide, while the residual slag is sold to cement plants.
