THICKENERS AND FILTERS innovations include the EvoLute NT dilution system , a new solution for diluting thickener feed that uses the overflow liquid from the thickener to dilute incoming slurries or suspensions to the optimum solid-liquid ratio ."
This new , patented system is designed for flow rates between 600 and 9,000 m3 / h . The dilution system does not interfere with the thickener settling process and can also accommodate slurries with low pH values . With the different flow rate configurations available , each system can be adjusted to the individual customer ’ s needs . The high dilution flow rates that the ANDRITZ EvoLute NT dilution system achieves translate into cost savings through lower power consumption .
On the thickeners themselves , a recent development is the ANDRITZ EcoSET , a costefficient thickener range that handles light to medium duty solid-liquid separation . With its plug-and-play control system , the ANDRITZ EcoSET thickener is a modular and standardised unit that reduces engineering requirements and delivery time .
Lastly , lithium plays a big role in creating a green future due to its ability to store large amounts of energy . ANDRITZ Separation has just developed the LiKoSET thickener , a bespoke solution to ever expanding lithium , but can also fit for potash , salt and chemical industries . This new thickener in ANDRITZ portfolio is built from
high quality duplex stainless steel which contains a high chromium content to prevent corrosion ( thus suitable for corrosive and humid operational conditions ), increased strength compared to other stainless steels , and is easy to maintain ( low maintenance required and easy to clean ).
WesTech ’ s take on HDTs
Matthew MacGoffin and Jerold Johnson at WesTech Engineering discussed with IM how filtration performance is affected by the thickener upstream of the filter . “ With proper selection of the thickener type and operation , this dependency can be used as an advantage .”
In a mine tailings operation , filters are typically the final dewatering stage before the solids are sent to a dry stacking or used in mine paste backfill . “ Dry solids throughput is a common design parameter when sizing filters , but water volume in the feed is critical . This is where the thickener comes in . The volumetric filter feed rate is achieved at the thickener , there is a direct correlation between reducing the form time and the water volume of the filter feed . There are several improvements to the thickener that can reduce the water sent to the filter , including retrofitting with a modern feedwell design , revising the control strategy , or installing a paste-type thickener .”
“ Most conventional feedwells are only capable
of providing adequate mixing near the feed pipe ’ s entrance . The rest of the feedwell is underutilised , and thus , the overall may be below if . Due to this inherent defect in the feedwell design , an operator is forced to add additional flocculant . The effect of this over flocculation is that solids compaction is hindered and the underflow density is decreased .”
To counter these known issues of the tangentially feed feedwell designs , WesTech introduced the EvenFlo ® feedwell . The EvenFlo consists of a two-stage design , where feed enters an inner raceway ( first stage ) and then flows radially into the outer feedwell ( second stage ). The result of this simple design is that the radial flow prevents short-circuiting and provides sufficient mixing such that flocculant dosage can be reduced and optimised . When thickeners are retrofitted with an EvenFlo feedwell , the improvements include a reduction in flocculant dosage , reduced operating costs , and an increase in the underflow wt % solids . All of this means that the optimisation of the feedwell will reduce the flocculant consumption giving reduced operating costs , and reduction of volumetric flow to the downstream filters .
WesTech also argues that increasingly , the High Density Thickener ( HDT ) is being selected as the preferred thickener model to work in conjunction with a filter . “ High-density thickeners incorporate some unique design features when