[ Super Duplex ]
[ Super Duplex ]
Splitter box to handle the flow of acids of differing concentrations after the evaporator stage .
A heavy duty mixer with the shaft fabricated from plate rather than bar , with bolted blades for easier replacement . phosphate rock , so different plants may experience varying conditions .
••
Localised corrosion under deposits during filtration . The design and operation of the process might also encourage more challenging conditions than anticipated . Despite agitation , dead spots can occur within tanks and pipework , and deposits during filtration could also accelerate corrosion .
Ferralium 255 meets the challenge Fortunately , the attractive properties of super duplex stainless steels are well suited to these myriad challenges , leading to their ongoing use in equipment throughout fertiliser production processes worldwide . Rodney Rice , director of Langley Alloys shared , “ We have supplied our Ferralium 255 ( S32550 ) super duplex stainless steel grade to projects over many years . Various technical papers have demonstrated its superior performance over more highly alloyed , and therefore more expensive solutions , such as the superaustenitic stainless steels Alloy 904L and Alloy 254 . This can be attributed to the
combination of desirable physical and mechanical properties – combating the combined effects of abrasion and corrosion . The higher strength makes for more effective material use – reducing the weight and cost of fabricated components , so it ’ s a win-win for end users .” Ferralium 255 was the first commercial grade of super duplex stainless steel available , having been patented by Langley Alloys in 1968 . This grade is built around a 25 % chromium content , utilising nitrogen as a cost-effective alternative to nickel , reducing the alloy ’ s cost whilst increasing its relative resistance to pitting corrosion . The other significant part of its composition is the inclusion of up to 2 % copper , known to be particularly effective in resisting sulphuric acid – an effect also used in other copper-containing alloys such as Alloy 825 and Alloy 20 . In bar form , the yield strength is higher than alternative grades , achieving > 85ksi compared with > 80ksi for others . Rice continues , “ Ferralium was produced under licence by Haynes International in the USA throughout the 1980 ’ s , and they did an excellent job of demonstrating its performance in use . Although we like to mention the use of Ferralium 255 in the refurbishment of The Statue of Liberty , the most valuable work was done convincing the many operators of its virtues in industrial applications . In later years , after the Langley Alloys patent had lapsed , Industeel also promoted a similar grade under their Uranus 52N + designation , for this application . The result of that collective effort is a continued demand for Ferralium 255 from end users that have had positive experiences in their operations .”
Ferralium plate & bar “ The images shown include a range of components fabricated by Metalcraft Inc ( USA ) from recent projects ,” continues Rodney . “ They include a very large agitator , fabricated from plate rather than using a solid bar shaft , together with bolted blades to allow their straightforward replacement . The ‘ splitter box ’ serves as a distribution point for phosphate ( P 2 O 5 ) solution coming from the evaporators ( at 28 %, 40 %, and 50 % acid concentrations respectively ) going to primary storage tanks . Its design has been customised by the plant operators
Pipework section complete with inspection hatch .
A pipework reducer , stepping between sections of different diameters
32 Stainless Steel World April 2024 www . stainless-steel-world . net