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Developing filtration plants – key challenges

Recent developments in tailings filtration have substantially increased unit capacities, making filtration plants up to 100 kt/d feasible for future plants requiring dry stacking of their tailings. In fact, more and more customers across the globe are shifting to dry stack tailings.

Implementing a filtration process can be challenging, from flowsheet selection to ramp-up and eventual performance and capacity. Alongside the financial aspects, customers must evaluate executional and operational factors while selecting the most feasible solution.

Some aspects to consider might be:

• How to deliver an accurate CAPEX & OPEX filtration trade-off?
• How to operate safely and efficiently, while maximizing uptime?
• How to manage on-time and on-budget project execution given multiple stakeholders?
• Most importantly, how to obtain an integral service package as capabilities are widely scattered in the industry?

Seeing the bigger picture

With more than 15 years working with filtration plant configurations, we've seen customers conduct cost evaluations and quote comparisons focusing on the equipment level. Strong focus on equipment-only is due to many reasons, but often the reason is simply a conventionally split project execution model, where technology suppliers and EPC/M service providers are all evaluated as individual portions, instead of considering holistic performance driven package. This approach can lead to unexpected costs later, as factors such as the required auxiliaries, steel structures, piping, and so on, may not be well estimated. Evaluating the entire plant configuration is crucial for accurate cost assessment. Hence, it would be beneficial for customers to shift to a holistic approach considering total investment and ownership costs, instead of an equipment-only focus.

Starting strong with correct sizing and early testing

Ensuring your processing plants’ maximum performance and competitive advantage starts in the early phases of a project. Sizing the technology correctly is the key to success, whether it is an equipment supply or a system level scope. As the feed characteristics are always case specific, accurate sizing with all the required auxiliaries requires testing. Testing at the very beginning of the project is the most affordable way to reduce the overall investment cost and the associated risks. 

Metso offers comprehensive testing capabilities along with a strong focus on innovation and R&D. With decades of testing experience and a global database of over 14,000 test cases, our Dewatering Technology Center serves as a comprehensive resource for all testing needs. From bench-scale to laboratory and pilot testing, Metso provides end-to-end support to develop optimized and sustainable flowsheets.

Plant design - Balancing complexity and clarity

Moving forward from testing and sizing during case development, it is possible to develop a business case and generate initial estimates using factorization methods based on literature-derived factors. While this approach allows for a quick estimation of the total investment, it can easily lead to incorrect evaluations and investment decisions. The primary issue is that general process plant cost estimation models are often a poor fit for filtration technology. Filtration does not adhere to the typical costing principles, making the process more complicated, especially when pre-designed concepts or products are not available. The accuracy of estimates is further compromised when assessing multiple filtration technologies, each with significantly different cost structures at the plant level.

Moreover, various sizes of filtration plants utilizing similar technology do not follow a linear cost path. Typically, more advanced filtration technologies result in a larger proportion of the total cost attributed to equipment. However, the overall price could remain the same or even more cost competitive. This nuance is often overlooked when using factorized estimations without considering the details. The key question worth pondering at this stage is that, if there’s two or more suitable technology options, how are we supposed to make the correct decision beyond technical and performance aspects – by focusing on the equipment prices or should we instead look at the total plant costs?

At Metso, our extensive experience in advanced filtration solutions has shown that the design of a filtration plant can make or break a project. This applies to both large-scale and smaller capacity filtration plants. Our mission is to take a holistic approach to every project to provide the best possible solution and service support in terms of technology and filtration plant design.

Creating an optimized plant design with specific filtration technology requires specialized experts, who have extensive experience on the particular technology. However, those are few and far between even on a global scale. Alternatively, designing a plant without a professional who specializes in the field comes at an elevated risk and higher costs. With decades of experience in filtration, Metso has attracted world-class filtration specialists throughout the years, who are readily available to support customers - all the way from testing, case development, to implementation and life cycle services.

Comprehensive filtration plant units

As in every process step in various industries, filtration is not different; A well-functioning, safe and operator friendly process is not achieved only by having good filters. The auxiliary systems, including EIA, which are serving the filter, may as well impair a good technology’s performance. That’s one of the reasons why Metso developed the Filtration Plant Units offering to maximize operational reliability in diverse types of dewatering applications where superior process performance combined with energy and water efficiency are required.

The Larox^® PF and Larox® FFP Filtration Plant Units have been specifically designed for the dewatering of concentrates, tailings, and industrial applications. Our modular and advanced plant units bring operational reliability, scalability, and safety to the forefront by combining in-depth expertise and a comprehensive scope, assuring solid performance and proven results. These modular and advanced Filtration Plant Units come as complete customizable solutions to meet customer needs. By using pre-designed plant products, this also enables accurate cost estimations for sites.

In focus: Larox^® FFP and tailings filtration

The Larox^® FFP filter family stands out for its ability to handle high-volume processing across various applications. Utilizing advanced technology and a design focused on reliability and easy maintenance, the Larox^® FFP filters offer multiple key benefits. Not only do they optimize dewatering processes, but also contribute to significant long-term savings, thus making them an invaluable asset for any mining operation.  

Being part of Metso Plus offering with a focus on resource optimization, the Larox® FFP 3716 filter is a trusted solution for the industry's growing volume of tailings and water scarcity challenges. Dewatering and dry stacking tailings help minimize environmental impact and risks associated with tailings storage facilities. One of the significant advantages that the Larox® FFP 3512 and Larox® FFP 3716 models can offer is the hole-less filter cloths feature. What does this mean for your operations? 

• No filling shoes are required to be mounted on the cloths, leading to reduced downtime and lower maintenance costs
• The filter can handle ~14,000 t/day of course or sandy tailings and ~10,000 t/day of fine or clay tailings
• Increased availability resulting in more tons per hour
• Lower air consumption during air drying is due to eliminating bypassing on the filling shoe
• Simple to install, maintain, operate and remove
• Guaranteed consistently low cake moisture

A Filtration Plant Unit with optimized design for a total capacity of > 50,000 t/day could look like the following illustration. Metso has designed its filtration plants with a variety of adaptable flowsheet options, serving as a foundation that can be customized to meet specific customer requirements. This development, carried out in collaboration with multiple stakeholders including our site service teams, has significantly enhanced our expertise and understanding of various design features. Through this process, we have gained deep insights into the advantages and limitations of different design approaches. As a result, our focus extends beyond what is technically possible to also identify and avoid potential design pitfalls.

Every filtration system requires a well-designed plant and supporting functions to operate efficiently. To achieve the maximum designed throughput, cost-effectively and safely, these elements must be perfectly engineered to reliably serve the core filtration technology. Regardless of the project’s implementation model, Metso’s Filtration Plant Unit, backed by a team of dedicated filtration experts, is ready to assist operations throughout the entire filtration journey. From leading our industry to learning from our history, Metso expertise enables operations to increase performance, profitability, sustainability and more. That’s why, together, we are the partner for positive change.