FILTRATION
The market for filtration in mining is growing , driven particularly by a high level of interest in filtered tailings solutions as mines look to dry stacking as an alternative to wet TSFs , reports Paul Moore
Factoring in filters
To get a global view on filtration from the industry ’ s new merged giant of mineral processing Paul Moore spoke to Metso Outotec Vice President for Filters Jussi Venäläinen about its combined approach to the market in terms of portfolio , customer segment and services .
On the combined product range , he told IM : “ If you think about the two filtration product portfolios before the merger – Metso had the VPA and the VPX filter as well as Tube presses – Outotec had no less than 12 different Larox filtration technologies including the Larox PF pressure filter and Larox FFP membrane filter press but also ceramic filters , vacuum disc filters , horizontal vacuum belt filters and others . But many of these are serving specialist markets and so the only overlap we really have is on the Larox FFP membrane filter press versus the Metso VPA and VPX . The Metso Tube presses are actually complementary to the Outotec range .”
Venäläinen said Metso Outotec is in the middle of doing in-depth studies to decide from a technical perspective but also a customer perspective which of the models it is going to keep – each has its own design benefits but it doesn ’ t make sense to keep two similar and overlapping products in the portfolio . “ And these studies involve evaluation of the best aspects of designs that were based on decades of R & D
Metso Outotec Vice President for Filters , Jussi Venäläinen
work – so it is challenging but also our combined portfolio has huge potential . Both companies were strong across a range of mined commodities , whether it be iron ore , copper , gold and others . Then there are the industrial minerals which have their own requirements and challenges as the materials and customer base are very different and this market will also greatly benefit from the combined Metso Outotec offering not only in filtration but across all the main mineral processing areas .”
Looking at the whole Metso Outotec filtration business , this has now been divided into three separate groups in market application terms to help us drive forward product development – these are Tailings filtration , where the company also expects the biggest growth potential ; Concentrate filtration and the filter types that involves ; and then a third category which it calls CPI filtration for Chemical Process Industry , which covers industries like pharmaceuticals , starch , bioplastics , organic pigments etc though it also includes many special non-metallic minerals markets from borates to alumina , TiO 2 , silicates , talc , and PCC . “ These customers have different needs to the mainstream mining customers – you are selling often a whole unique process not just the equipment to fit into part of an established mining process .”
All three groups have their own nuances . “ For example , in tailings , there you need to be able to handle huge volumes but the filtration itself is relatively simple ; pumping , squeezing and airdrying the cake to a desired moisture content . Concentrate filtration involves lower volumes but also a very precise final moisture content . For CPI the filtration process characteristics are completely different and can include different washing cycles , for example . In CPI not only the filter cake but also the filtrate can be a product ,
There are big challenges in scaling up filter presses to be able to cope with the world ' s copper and iron ore tailings operations if they go down the filtered tailings route , but FLSmidth was proactive and built a demonstration unit in Tucson which has the largest pressure filtration plate ever put into service
where you are using the filter as a washing device .”
Finally , the process itself dictates the approach depending on the feed solids content or particle size distribution or temperature of the feed . “ So when you are choosing a filter for a project it is driven by the customer requirements – what is the production capacity , what is the desired residual moisture content , how much footprint space is available , are there other filter types already in an existing plant on the site where you may want to optimise the service and spare parts approach .”
Venäläinen commented : “ We have today in Metso Outotec 14 main filter types and the three market application groups – so to some extent we are in a unique position to mix and match depending on the situation . Take the Larox PF filter as an example – it can be used for both copper in concentrate filtration as well as starch in CPI filtration . In the tailings market , the customer needs to deal with very large volumes , but the fact that there is no revenue in the ‘ product ’ means they are careful when considering large investments in tailings management . That said , it is also a very necessary and increasingly scrutinised part of their operations , and one that is being driven by sustainability & environmental requirements / regulations , but it also gives mining customers a social license to operate . For the scale and cost reasons the large membrane filter presses are really the only option in tailings .
OCTOBER 2020 | International Mining 37