Emission Control in Sulphuric Acid Treatment Plant, HIL - Birla Copper, Dahej, Gujarat

Abstract

Being the world`s 2nd Largest producer of Copper Rods and leading copper producer in India, serving over held of the Indian demand for refined Copper. The process involves electrolytic ally refined, 99.99% pure, continuous cast Copper rods, O2 free rods, from LME grade copper Cathodes. Sulphur Acid treatment of copper cathodes is primarily used in the electro winning process, where copper is extracted from a solution containing Copper Ions and purified – in this process sulphuric acid acts as an electrolyte. Since, Sulphuric acid being used is very highly concentrated hence, the associated environmental damages and risks are high too. This paper will describe various technology options including: Flue Gas Desulfurization System, Spray Dryer Absorber (SDA), Circulating Dry Scrubber (CDS), Limestone-based Wet FGD, Low NOX burners, Selective Non-Catalytic Reduction, Electrostatic Precipitator, Bag House Dust Collector, all of which have been evaluated and installed extensively to reduce SO2, NOx, PM and other emissions. As each technology having advantage and disadvantage, for each of the technologies considered, major features, potential operating and maintenance cost impacts, as well as key factors that contribute to the selection of one technology over another are discussed here.

Introduction

Industrial development is key to economic growth, and copper plays a crucial role in infrastructure and technology. India’s demand for copper has surged due to rapid urbanization, with Hindalco Industries Ltd. – Birla Copper (Dahej, Gujarat) being a major supplier. A central process at this facility is sulphuric acid treatment, vital for refining copper using electrowinning techniques. This process, however, generates hazardous emissions like sulphur dioxide (SO?), nitrogen oxides (NO?), acid mist, and particulate matter (PM), which pose environmental and health risks.

Problem

Current pollution control systems show inconsistent performance, especially during seasonal changes, and sometimes fail to meet regulatory limits, impacting air quality and health.

Purpose & Objectives

The study aims to:

• Analyze emissions from the acid treatment process.

• Assess pollution control technologies (scrubbers, ESPs, mist eliminators).

• Identify emission spikes and their causes.

• Recommend technological upgrades and strategies aligned with CPCB and WHO standards.

Scope

Focused specifically on emissions from the sulphuric acid treatment section of the Dahej facility, not other operational units.

Literature Review Highlights

• Emission control evolved from reactive to preventive approaches.

• Common pollutants:

  • SO? – causes acid rain, respiratory issues.

  • Acid Mist – hazardous H?SO? aerosols.

  • NO? – contributes to smog and ozone issues.

  • PM10 & PM2.5 – linked to lung and heart diseases.

• Technologies reviewed include:

  • SCR, ESP, Wet Scrubbers, FGD, Wet ESP.

• Regulatory standards are defined by CPCB and WHO, with WHO limits generally stricter.

Facility Description

Hindalco’s Dahej plant is a major integrated copper facility with a key sulphuric acid unit. Its coastal location benefits logistics but increases environmental sensitivity.

Sulphuric Acid Treatment Process

• Uses H?SO? in copper electrowinning.

• Emissions arise from acid mist, chemical reactions, fuel combustion, and dust from materials handling.

Emission Sources

• Acid mist vents

• Stack emissions (SO?, NO?, CO?, trace metals)

• Dust collection inefficiencies

• Fugitive emissions from leaks/spills

Existing Control Measures

• Scrubbers, ESPs, Mist Eliminators, and Dust Suppression systems are in place.

• Performance varies with seasonal factors, showing reduced efficiency in summer.

Conclusion

A. Summary of Key Findings This research has thoroughly evaluated the emissions originating from the sulphuric acid treatment unit of the HIL – Birla Copper plant. Seasonal data collection and analysis have revealed the following insights: • SPM and SO? levels often exceed prescribed limits during the summer season. • NO? and CO? concentrations fluctuate with ambient temperature and combustion efficiency. • Acid mist, though within legal limits, remains close to occupational thresholds, necessitating immediate technological and procedural improvements. B. Achievements and Contributions • Comprehensive identification of emission patterns across different seasons. • Detailed evaluation of existing pollution control equipment. • Recommendations for cost-effective upgrades and modern emission control techniques. • Emphasis on occupational health and environmental sustainability. C. Future Scope Future research can focus on: • Carbon footprint assessment of the entire facility. • Life-cycle analysis of emission control technologies used. • Exploring renewable integration and low-carbon acid production processes. D. Final Thoughts As industries move toward environmental accountability, facilities like HIL – Birla Copper must adopt proactive emission control strategies to ensure operational sustainability and compliance with global standards. Through this study, it is evident that system upgrades, real-time monitoring, and dedicated environmental governance can significantly reduce pollution and reinforce India’s commitment to cleaner industrial growth.

References

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Copyright

Copyright © 2025 Rupesh Kumar Banerjee, Abhijit Mangaraj. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.