Outotec® Ettringite Process

Outotec® Ettringite process

The Outotec® Ettringite process is a solution for managing sulfate and calcium in process streams for the production of water that meets discharge water quality requirements and allows the recycling of treated water for reuse. The Benefits process consists of an ettringite precipitation stage at • High quality treated water pH 11-13 using lime milk and aluminum, followed by a (for recycling) final neutralization stage using carbon dioxide. Gypsum • Easy integration to other processes precipitation can be included before the ettringite stage, and plants when required. • Easy to expand for further Ettringite precipitation is an easy and flexible process with treatment needs simple and understandable chemistry. It can be applied • Process guarantees and tailoring via for sulfate removal from gypsum saturated waters. More client water testing importantly, sulfate can be precipitated even when it is associated with highly soluble sodium and potassium sulfates. The sulfate concentration after treatment is typically 200-1000 mg/L. A level below 200 mg/L can be achieved with enhanced precipitation chemistry. In addi- tion to sulfate removal, the Outotec Ettringite process includes advanced removal of metal impurities such as Ni, Cd, Cu and Zn as metal hydroxides. The final products of the ettringite process are treated water with a low sulfate concentration for discharge to the environment or re-use and stable, solid precipitate with a high buffer capacity. ETTRINGITE PRECIPITATION NEUTRALIZATION LIME MILK ETTRINGITE CLARIFIER CARBON DIOXIDE ALUMINUM CHEMICAL FLOCCULANT NEUTRALIZATION CLARIFIER FLOCCULANT Finland, April, 2014

FEED WATER ETTRINGITE SLURRY CLARIFIED OVERFLOW NEUTRALIZED WATER TREATED WATER

SOLIDS RECYCLE

CLARIFIER UNDERFLOW PRESSURE FILTRATION

SOLIDS TO FILTER FILTER CAKE

Our offering Process solution examples • Tailored and optimized water treatment solutions for • Control of sulfate in discharge water: effluent treat- improving environmental quality and reducing scaling ment plant to manage sulfate concentration in concen- potential trators, mines and process effluents • Based on globally available aluminum and calcium • Reduction of scaling to improve plant availability: chemicals, which are selected specifically for each removal of sulfate and calcium prevents scaling and case reduce scaling-related maintenance costs • One-stop-shop concept from testing up to EPC • Efficient water recycling: removal of gypsum satura- • Highly automated solution minimizing operational tion enables water recycling within the process and costs decreased fresh water intake requirements. Also • High-quality treated water (for recycling) effluent volumes can be optimized by efficient overall • Process guarantees and tailoring via testing of client’s plant water management. water • Environmental benefits: • Optimized chemical consumption Typical industrial areas • Water recycling • Non-ferrous concentrators • Control of sulfate discharged to environment • Gold plants • Coal mining • All mine sites with sulfidic ore

Key offering includes • Tailored water treatment solutions to optimize the entire plant’s water recycling and reuse • Engineering and implementation • Research and development (e.g. conceptual and feasibility studies) • Plant engineering • Project implementation (up to EPC) • Life cycle services

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