INNOVATORS OF ZINC - WHAT GETS MEASURED; GETS MANAGED…

Induced Fan Duct is a critical equipment of Boiler in Captive Power Plant (CPP) and its malfunction would lead to breakdown of boiler. CPP at Chanderiya has been facing a major challenge of erosion of duct parts of Induced Draft Fan, leading to higher power consumption, thereby, increasing COP.
To eliminate the erosion, Captive Power Plant team comprising Mr. Mahender Singh Rathore (Manager -  Engineer and Planning), Mr. Seela Satyanarayana (Associate Manager - Electrical), Mr. Mohd. Parvez (Associate Manager - Power), Mr. Chandi Das (Associate Manager - Electrical) and Mr. Binu Raphael (AGM - Asset Optimisation) conducted a detailed “Computational Fluid Dynamics” analysis by taking measurement of pressure drop across the duct. Huge pressure drop across the duct was found to be the main reason of erosion during the analysis. Team then rectified the flow path of induced air by modifying the design of the duct.
Team efforts paid result. After design modification, the erosion of duct got reduced and power saving of around 100KW/Unit was achieved leading to cost saving of Rs.
30 lakhs per annum. This has been horizontally implemented across all units of HZL.

SAFETY TOWN HALL AT CHANDERIYA SMELTING COMPLEX - 25TH MAY, 2017

"I had a wonderful interaction with Hindustan Zinc employees at Chanderiya on being-safe for themselves and their families." Sunil Duggal, CEO HZL

HINDUSTAN ZINC TO INVEST RS. 570 CRORE ON 'ZINC FUMER PLANT' TO BOOST VOLUMES

Hindustan Zinc, India's only and the world's leading zinc-lead-silver producer is all set to commission its first Zinc Fumer Plant to extract metals from the waste.

The most advanced global zinc production technology, hydro-metallurgical, generates Jarosite as part of the metallurgical process to produce zinc. Due to generation of Jarosite waste as part of the process, there has been a significant loss of metals like zinc, lead, copper, silver and other minor metals in the waste. Globally, the zinc-lead mining industries have been facing challenge towards recovery of metals from waste.

Industry sources estimate that Hindustan Zinc loses about 27,000 MT of metal per annum in this waste.

The most successful process for recovery of metals, without the formation of Jarosite, is Zinc Fumer Plant.  Currently Zinc Fumer Plants are installed in few Chinese and Korean Zinc plants and are quite successful. Zinc Fumer Plant not only deviates from the process of formation of Jarosite, instead, recovers the metals from the waste.

CEO of Hindustan Zinc, Mr. Sunil Duggal informed  that “Hindustan Zinc has placed formal order to China Non Ferrous Metal Industry's Foreign Engineering & Construction Co Ltd (NFC) and we are expecting to commission the first Zinc Fumer Plant by Middle of 2018.  The first Zinc Fumer Plant is being commissioned by Hindustan Zinc at Chanderiya with a cost of Rs. 570 crore will improve recovery of Zinc from 96.8 % to 97.5% (from MIC) that would add about 3000 tonnes of Zinc from just one smelter per annum.” While treating waste, the Zinc Fuming Plant will also produce a large quantity of slag that would be fully utilized by the cement industry.”

The major recovery from Zinc Fumer Plant would be in Lead and Silver, an increase of Lead production by about 4700 tonnes and Silver by 33 tonnes per annum. The Chanderiya Hydro-II Smelter of Hindustan Zinc has a capacity to produce 210,000 tonnes of Zinc.

Hindustan Zinc has an overall current capacity to produce about 825,000 tonnes of Zinc, 180,000 tonnes of Lead and about 500 tonnes of Silver.

The Company has plans to put-up Zinc Fumer Plant at its other Smelting Complexes - at Hydro-I in Chanderiya and in Rajsamand at Dariba Smelting Complex. Once the commissioning is completed at all the three locations, the capacity of Zinc, Lead and Silver is likely to increase significantly, which would ultimately add to the overall volumes, revenue and profits of the Company.

INNOVATORS OF ZINC - PRODUCING 200M3 WATER PER DAY FROM UNUSED STEAM…

Hydro-I plant at Chanderiya Smelting Complex, commissioned in 2005 generated about 43-45 tonnes of steam from Waste Heat Recovery Boiler which is used to generate power in condensate type turbine of 9.40 MW. During this process, about 25 tonnes of steam gets condensed and remaining 20 tonnes is used for leaching process. Since leaching LP steam requirement is about 35 tonnes, the remaining 15 tonnes steam needs to be taken from CPP.
To reduce the cost of steam from CPP, in 2012 condensate type turbine was replaced by 4.3 MW back pressure type turbines. Due to this, the excess steam of 6-8 tonnes/hr started venting off through final vent. This contributed to water loss of about 150 m3/day.
A team comprising Mr. Deepak Jain - AM, O&M, Mr. Kailash Chandra Choubisa - AM, E&I, Mr. Sunil Dutta - Executive, O&M, Mr. P.C. Kumawat - AM, O&M, Mr. Bhagwan Lal Dhakar - Executive, O&M of Unit-II under guidance of Mr Rajesh Luhadia - Unit Head, Unit-2  brain-stormed for utilization of this vent steam as part of water conservation project.
The team came up with an innovative idea to utilize the available spent heat exchanger to arrest the unutilized 6-8 tonnes of vent steam.
A condensing system was connected before the final vent to convert the excess steam into condensate water and recycled the same into the boiler circuit. Due to additional in-built capacity of condensing system, vent steam of Hydro-2 Roaster could also be condensed with the same system. This lead to water recovery of more than 200m3/day against target of 130m3/day from unused steam.

INNOVATORS OF ZINC - RECOVERY OF ZINC FROM SLAG IN LEAD AUSMELT PLANT BY OPTIMIZING IRON AND SILICA RATIO IN CONCENTRATE

The Ausmelt furnace at Chanderiya produces Lead bullion using Lead concentrate and is designed to handle 3.9% Zinc and 5% Graphitic Carbon. Higher Zinc in this concentrate results in higher Zinc percentage in slag and higher Graphitic Carbon results in poor separation of slag from Lead bullion. It also lowers the life of the lance.

Since September 2016, Ausmelt plant was getting Lead concentrate with 6-9% of Zinc and 5-16% of Graphitic Carbon which was more than the optimal percentage of Zinc and Graphitic Carbon.

A team led by Mr. Pranabesh Roy - SBU Head and comprising Mr. T.V.S.S. Nagaraju - AM, Process, Mr. Vinay Kanthalia - AM, Process, Mr. Shyam Goswami  - Jr. Executive, Process, Mr. Vivek Menaria - Jr. Executive - Process, Mr. Sandeep Paliwal - AM, Mechanical and Mr. Anil Inani - AM, Instrumentation as team members took the task to overcome this challenge.

It was studied and observed that when the ratio between Iron to Silica (Fe/SiO2) is more than 0.9 and Zinc is above 20-22% it results in formation of severe build-up inside the furnace. Also, to control bath temperature due to high Graphitic Carbon, Ausmelt furnace needs at least 25-30 MT/day of extra secondary material. The only in-house secondary material available was ISF dross which contains 25-30% Zinc and 55-60% Lead.

The team studied the effect of Zinc and other impurities like Iron & Silica in slag. To maintain the ration of Iron to Silica (Fe/SiO2) below 0.9, Silica was added as flux which brought down the ratio to 0.6 to 0.7 and thus was able to handle 32-35% Zinc in slag.

The team was successful to use high Zinc and Graphitic Carbon concentrate and was able to consume 800-1000 MT per month of ISF dross inventory which otherwise was increasing every month. Optimization of this slag chemistry also helped to get highest lance life ever (6 batches per lance) for the month of December 2016 with record of 16 batches for a single lance. This increased the average life of lance by 3 times.