Separator's Digest 2004/1 - GEA Westfalia Separator Group

➤The Physics of Separating Technology Using CentrifugesThe fundamental formula for the settling process of particles is provided by Stokes.According to this formula, the settling velocity is related to the square of the diameter ofa particle. This physical law provides optimum conditions for using centrifuges, eitherdecanters or separators for recovering and classifying minerals in the low µm range. Thecentrifuge is able to recognize the difference between particles with a size of 1 µm and 2µm extremely, namely with a factor of 4 according to Stokes. This fact means that the centrifugaltechnology of Westfalia Separator is extremely efficient for recovering minerals.such a way that the user obtains thedesired quality with minimum losses. Ayield which is increased by several percentagepoints and a higher degree ofwhiteness make themselves felt ininstallations which produce thousandsof tonnes per year. Relatively smallquality improvements boost profits significantlyin this industry.Newly developedrecovery processlia decanter, the current product losscan be converted into the requiredhigher quality without any problem.The pay-back period of this process isvery short.Based on the test results using atest decanter CA 225, the pay-backperiod of the 2 µm recovery processwith a high-performance decanterCCA 635 is an estimated nine months.Around 1.9 tonnesper hour can be recoveredwith thisKim Traegersystem.Assuming 8,000operating hours peryear and a price ofapprox. USD 80 perWith a newly developed recovery process,Westfalia Separator has succeededin significantly reducing the lossesof the 2 µm fraction. By connecting asecond classifying stage with a Westfatonnefor this quality, the additionalproceeds total approx. USD 1.2 millionper year. At the same time, the manufactureris able to continuously producetwo different pigment qualitieswith the first and second stage. This isbecause the paper industry is constantlysearching for new pigment formulationsand recipes. This provides addedvalue for the user. ■Head of Mineral Processing, Business UnitChemicals, Pharmaceuticals, BiotechnologyWestfalia Separator Industry, OeldeTel.: + 49 25 22/77-16 35traeger.kim@gea-westfalia.deSeparator´s World23Separator´s Digest 1/2004