Outotec Arsenic Removal Process

OUTOTEC ARSENIC REMOVAL PROCESS

The Outotec Arsenic Removal Process is a solution for managing toxic arsenic in process and effluent streams. The process consists of a ferric arsenate precipitation stage followed by neutralization using lime milk. The BENEFITS process is based on easy, robust and understandable • High process reliability precipitation. The treatment of toxic arsenic requires a • Improved environmental quality and high level process reliability. This can be guaranteed using stable residues the cost-effective Outotec Arsenic Removal Process. • Safe working conditions After the arsenic removal process the treated water has • Process generates water that meets a low arsenic concentration, typically containing 1-3 environmental regulations mg/L arsenic. If an even lower arsenic concentration is • Process guarantees and tailoring via required, a polishing step with enhanced arsenic removal client water testing can be included. The process comprises the neutralization of acidic streams and the advanced removal of metal impurities, including Ni, Cd, Cu, Sb and Zn. The final product of the arsenic removal process is treated water that can be safely discharged to the environment or recycled back for process use. The selection of the arsenic treatment process is governed by residual stability. The residue of the Outotec arsenic removal process is a stable solid precipitate, which will pass the EU CEN and US EPA TCLP leaching tests for hazardous, arsenic containing solid waste. Iron sulfate Lime milk Finland, April, 2016 Flocculant Arsenic stream

Ferric arsenate slurry

Treated water for discharge and re-use Air

Air

Air Outotec Larox PF

Ferric arsenate ﬁlter cake

Filtrate water

Our offering Most typical industrial areas for the application: • Tailored and optimized arsenic water treatment solu- • Non-ferrous smelters and roasters tion to improve environmental quality and produce • Sulfuric acid plants stable residue • Gold plants • Based on globally available, economical iron and calcium chemicals and low-cost oxidants, including air Key offering • One-stop-shop concept from testing up to EPC • Tailored arsenic treatment solutions with safe and • Reliable process operation for the treatment of toxic stable ferric arsenate precipitate arsenic • Optimization of the entire plant’s water recycling • Safe working conditions and controlled arsenic expo- in order to minimize production of arsenic- sure via efficient dust control containing discharge water • High automation rate, minimizing operation costs • Engineering and implementation • High-quality treated water • Research and development (e.g. conceptual and • Process guarantees and tailoring via client water testing feasibility studies) • Environmental benefits: • Plant engineering • Optimized chemical consumption • Project implementation (up to EPC) • Water recycling • Life cycle services • Control of arsenic discharge to environment Reference plants Process solution examples • Boliden Harjavalta Finland, Condensate Treatment • Control of arsenic in acid plant condensate: ferric process arsenate treatment plant to manage arsenic concen- • Plant design for Nicico Sarcheshmeh and Khatoon tration in acid plant effluent waters. Heavy metals are Abad acid plant effluent treatment removed in the lime milk neutralization stage along with sulfate, which precipitates as gypsum. • Efficient water recycling: water from the arsenic removal process can be recycled back to the process for reuse and the fresh water intake can be decreased. Total arsenic discharge and effluent volumes can be optimized by efficient overall plant water management.

Outotec provides leading technologies and services for the sustainable use of Earth’s natural resources. As the global leader in minerals and metals processing technology, we have developed many breakthrough technologies over the decades for our customers in metals and mining industry. We also provide innovative solutions for industrial water treatment, the utilization of alternative energy sources and the chemical industry. Outotec shares are listed on NASDAQ OMX Helsinki. www.outotec.com