By Riccardo Rume, CTO at MSE Filterpressen GmbH
To strengthen its production capabilities and optimize resource efficiency, Nyrstar has implemented a significant technical enhancement at its Hobart site in Tasmania. A newly installed membrane filter press now supports the solid-liquid separation stage within the established Roast-Leach-Electrowinning (RLE) zinc production process – a critical step that directly affects yield, process stability, and occupational safety.
Solid-liquid separation in the RLE process
The RLE process is a standard hydrometallurgical method in zinc production. Following roasting, the zinc concentrate undergoes leaching with sulfuric acid, producing a slurry that contains both dissolved zinc and solid residues. Efficient separation of these components is essential: inadequate filtration can reduce metal recovery, compromise product quality, and introduce operational inefficiencies further downstream.
Recognizing these challenges, Nyrstar sought to improve the consistency and efficiency of this process step, particularly in light of planned capacity increases at the Hobart facility. A robust and high-performing filtration system was required – one that could reliably manage larger throughputs while maintaining low residual moisture and high filtrate clarity.
Customized filtration solution from Germany
To meet these demanding process conditions, Nyrstar partnered with the German manufacturer MSE Filterpressen GmbH, a company specialized in industrial filter press systems. The selected solution: a fully automated membrane filter press engineered for chemical resistance, mechanical durability, and precise control across all stages of operation.
At the heart of the system are membrane filter plates, which first separate the slurry solids under mechanical pressure. After the initial filtration phase, the membranes are hydraulically inflated using water, compressing the filter cake further to significantly reduce its residual moisture. This dual-phase approach ensures high dewatering efficiency and improves the manageability of the resulting solids.
Materials and configuration tailored to site demands
Given the aggressive nature of the process environment – especially the presence of sulfuric acid –the system was built with PVDF (polyvinylidene fluoride) membranes due to their excellent chemical resistance. The press frame and contact surfaces are clad with duplex stainless steel, offering added protection and longevity under corrosive conditions.
To simplify transport and installation across the more than 16,000-kilometre supply chain, the filter press was designed as a modular unit, broken down into several transportable sections. This not only facilitated logistics but also ensured efficient assembly despite limited available space at the Hobart site.
Advanced automation and process safety
The entire filtration sequence is fully automated, including slurry injection, pressure management, plate movement, cake discharge, and filter cloth washing. Operator intervention is minimized, enhancing both process consistency and plant safety.
Integrated safety functions and intelligent sensors provide real-time feedback and protection, especially under the system’s high operating pressures of up to 15 bar. Uniform cycle times and automated control contribute to a steady production rhythm, reducing the risk of bottlenecks or unplanned downtime.
Worker protection and environmental efficiency
The press system features a fully enclosed design that isolates acidic slurries and minimizes vapor exposure. Automated cake handling further reduces the need for direct operator contact, aligning with Nyrstar’s strict occupational health and safety standards.
In addition to enhancing workplace safety, the reduced moisture content of the final filter cake supports more efficient downstream logistics – less energy is needed for drying or disposal, and material handling becomes safer and cleaner. These improvements also reduce the environmental footprint of the operation, contributing to more sustainable metal production.
Seamless project coordination
The 40-tonne filtration unit was shipped in stages from MSE’s manufacturing site in Germany to Tasmania via sea and land freight. Installation and commissioning were executed by MSE’s experienced technical team, in close coordination with the Nyrstar project management group. Despite tight spatial constraints and time-sensitive conditions, the system was installed and brought online according to schedule.
Riccardo Valerio Rumé is Chief Technology Officer and Co-Managing Director of MSE Filterpressen GmbH, a German engineering company specializing in high-performance filtration systems. With a background in automotive engineering and a passion for industrial innovation, he leads the development of advanced filter press solutions for challenging applications in mining, chemicals, and battery recycling. His focus lies in combining process efficiency, automation, and safety to drive sustainable progress in solid-liquid separation.
About Nyrstar
Nyrstar is a national multi-metals processing and refining business, operating in Port Pirie and Hobart for over 100 years to produce lead, silver, zinc, and many other materials that are essential for the manufacture of products used by everyone, every day.
Nyrstar Australia employs over 1,400 people across processing plants in Port Pirie and Hobart that operate as two interlinked sites and play a critical role in increasing the value of the metals and minerals obtained from resources sourced from across Australia and around the world.
Nyrstar is an international producer of critical minerals and metals essential for a low carbon future with mining, smelting and other operations located in Europe, the United States and Australia. Nyrstar’s operating business is wholly owned by Trafigura, one of the world’s leading independent commodity trading and supply chain logistics companies.
About MSE Filterpressen
Since its founding in 1978, MSE Filterpressen has become one of the world’s leading manufacturers of high-quality filter presses in the field of solid-liquid separation. With the filter press plants of MSE Filterpressen®, you get a wellproven and innovative solution for industrial separation processes. Our solid/liquid separation specialists use their in-depth expertise to engineer and provide filter press plant solutions that are individually tailored to regional and application requirements.
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