Cleaning up in the steel industry Steel wire rod must be thoroughly cleaned to give high-value plated wires and springs. The traditional cleaning method is wasteful and hazardous. Innovative plant enables small specialist firms to do the cleaning in-house - safely, cleanly and cost-effectively. Background W... Steel wire rod must be thoroughly cleaned to give high-value plated wires and springs. The traditional cleaning method is wasteful and hazardous. Innovative plant enables small specialist firms to do the cleaning in-house - safely, cleanly and cost-effectively. Background Wire rod is supplied by steel mills in two-tonne coils, and comes coated with a thin scale of rust. If this is not removed, it contaminates the wire drawing process. Mechanical cleaning, which removes about 80% of the oxide, is adequate for cheaper products such as nails. But for higher quality products, batch pickling is used. The entire coil is dipped in a 10,000 litre tank of hot sulphuric acid for 20 minutes. This is both dangerous and inefficient - after 250 tonnes have been treated, the action of the acid becomes weakened by the build-up of iron sulphate, and the entire tankful must be disposed of. The additional costs of environmentally safe methods of disposal make it uneconomical to handle less than 50,000 tonnes per year, putting the process out of the reach of smaller companies. Working partnerships In the recently completed Innovation project "In-line process for the electropickling of steel wire rod by integrated recycling machine", the Italian company Otomec, a manufacturer of specialised equipment for the steel processing industry, has developed a compact, fully-enclosed unit which successfully addresses all these problems. Extensive testing of prototype machines by Otomec and its partners, as well as by end-users in Portugal, Italy and the United Kingdom, have demonstrated wire production of consistently high quality with 70% reductions in cleaning costs. Description, impact and results Otomec's system combines existing technologies in a completely new way. The wire rod is fed from the coil through the cleaning machine and into the drawing apparatus in one continuous movement. The incorporation of mechanical cleaning, which removes all but the finest oxide particles before the wire enters the acid, greatly extends the life of the acid solution. As much as 200 tonnes of rod can be completely cleaned using a single tank of just 700 litres of acid. Small amounts of the solution are continuously drawn off and evaporated under vacuum, producing solid waste for safe and easy disposal, and recycling the acid for further use. The system offers potential savings of around 45 million euro per annum across Europe, and will particularly benefit the European sector's 500 SMEs. The British pilot plant is running 24 hours a day and, since the project finished, marketing campaigns in Italy and the UK have already produced orders for seven further units, two of which have been exported to Argentina and Taiwan.
