Outokumpu is an international stainless steel and technology company. Our vision is to be the undisputed number one in stainless, with success based on operational excellence. Outokumpu Technology own by the Outokumpu group is a global leader in designing, developing and supplying tailored plants, processes and equipment for the minerals and metals processing industries. The company offers solutions to processes of the customers and by adding value to their products and services. Outokumpu Technology operates in 16 countries and employs 1700 people, says Sales Manager Kristian Mattila.

The process engineer Lauri Palmu is responsible for the technology of export projects of the company's Copper recovery. He describes the different development steps of Rinotop's anode insulator:

• The OMG Kokkola factory needed anode insulators on 1999. The anode insulator is an injection mould plastic piece. Two of them are needed for the handling of an anode plate with a suspension bar. The task of the anode insulator is to keep the anode and cathode plates separate and helping to handle the cathode plates. Plates are lifted for maintenance from the diagonal cam of the anode insulator for about every other year. One anode plate has a weight of ca 100 kg and there are 85 anodes and 84 cathodes in the electrolytic cell altogether. In the factory, there can be even hundreds of electrolytic cells.

• The first anode insulators were manufactured as a normal Rinotop porcess. The product worked technically very well but later it appeared that the product was not strong enough in all process conditions. Plastic becomes brittle in acid as time passes. The first version was hard but as said very brittle and was easily broken by a strong impact. In the worst case, the lifter of the anode plates could be damaged and the whole operation of the production plant could be interrupted. In the process of the Kokkola factory, the Copper sulphate splashes occasionally and adheres to the locking system of the separator. The acid came inside the piece through a hole and copper sulphate started to expand gradually by damaging the insulator as a result.

Requirements set to the new anode insulator made 2004:

• Acid-proofness. The recovery plants have a solution containing sulphuric acid and copper sulphate.
• Temperature resistance. In normal conditions, the temperature of the process is about 50 degrees, but in exceptional cases it can rise up to even 100 degrees.
• Mechanical strength. Lead anode plates of ca 100 kg are lifted from the cam of the two anode insulators. In the export projects, hard treatments of the anode insulators must be prepared for; a hammer is unknown in many places and often a piece of iron or the like is used instead.
• The abrasion strength must be good.
• The material must not be conductive.

The development manager of Rinotop, Kari Kippilä summarizes:

• The implementation is a result of good cooperation with Outokumpu. Rinotop was responsible for the 3-D modelling, the mould manufacturing and the product manufacturing.
• The product dimensions were massive; many material tests and other testings were done simultaneously with the mould design and the machining; The best material showed to be the quality for film fabrication, not the one intended for injection moulding. The determination of the shrinkages was difficult due to the material and the required wall thickness.
• The manufacture and the production required several tests. The search for the manufacturing parameters was challenging due to the raw material and the exact application. The production was divided into four different places in accordance with a tough time schedule.
• End result: The customer got the insulators in time, the export deliveries ready and packed in containers. The pieces also stand hard treatment on work places. The whole project lasted from 17.2.2004 to 15.9.2004.