Europe’s largest stainless steel plant in Tornio, Finland, which is producing 1.7 million tonnes a year, opened a new slag processing plant in September 2010. The main components of this new plant are two powerful alljig® jigging machines, ordered by Tapojärvi, which runs the plant on behalf of Outokumpu. The slag, a by-product of steel production, still contains 5% – 10% metal, and the alljig jigging machines separate out this valuable metal for metallurgical reprocessing. The other product is metal-free slag that can be used as aggregate.
As raw materials are becoming increasingly scarce, there is a growing trend towards economical processing of by-product slag from ferrochromium, to ferromanganase and stainless-steel production. In turn, there has been a noticeable spike in demand for alljig jigging machines, particularly in Northern and Eastern Europe. Within the last five years, Allmineral has increased its market share considerably in these countries, with no end in sight.
On 8 September 2010 the residents of the town of Tornio on the Finnish-Swedish border were treated to a special visit from Mauri Pekkarinen, the Finnish Minister of Economic Affairs and senior vice president of Outokumpu. Both attended the official opening ceremony for the state-of-the-art processing plant at the largest stainless steel plant in Europe, which is also the biggest employer in the region.
Tapojärvi will run the new plant that makes it possible to extract the last bit of valuable metal from stainless steel slag. Air-pulsed alljig jigging machines are the core equipment of this process, and take advantage of gravity by using the difference in metal and slag density to efficiently separate the two. The machines, which are coming from Germany, are designed for capacities of 50t/hr – 100t/hr, while efficiently sorting particles ranging in size from 1mm – 32mm.
The Finnish corporate group Outokumpu is one of the largest producers of high-quality stainless steel worldwide. Its yearly melting capacity is around 2.5m/t, and its rolling capacity for warm and cold strip, long products and quarto metal sheets is just under 2m/t. The Finnish plant in Tornio is the affiliated group’s largest factory, and is unique in that it has the only fully integrated production line.
The aforementioned production line starts in the EU’s only chromium mine in Keminmaa, where approximately 200,000t of lump ore and 400,000t of fine concentrate are produced every year. The steel plant has two production lines: one with 100t and the other with 150t and converters in which the melted ferrochromium is processed with steel scrap. The warm rolling factory produces steel with widths ranging from 1m – 1.6m and with a thickness of up to 12mm. Most of the coils made are then turned into acid-resistant stainless steel sheets and plates at the cold rolling factory for customers all over Europe.
Due to the high separation density necessary, the alljig jigging machine is in many cases the only economical solution for producing high-quality metal that can be metallurgically reprocessed. In addition, the cleaned slag can also be sold as valuable aggregate for concrete or road construction.
In the first half of the decade, there was a great demand in Western Europe and Africa for Allmineral’s innovative processing technology but currently the spotlight is on countries in the CIS.
Initially, Allmineral set up two lines, each with two alljig jigging machines, for ferrochromium slag processing at the Russian metallurgical plant Cheliabinsk (one of the largest in Europe). Their throughput rate is 20t/hr – 40t/hr per machine.
Allmineral has now received an order for two alljig jigging machines to be used for upgrading the raw materials enrichment for ferrochrome-production, the chromite ore itself. And following their first order for an alljig jigging machine in 2007, another chromium ore processing plant, owned by the Kazchrom company in Chromtau, Kazakhstan, has just ordered another one.
Within a short amount of time, twelve alljig jigging machines for slag processing have been put into operation: two in Belgium, four in South Africa, four in Russia and two in Finland. In addition, there are also the aforementioned four alljig jigging machines for chromite ore benefication for clients in Russia and Kazakhstan. In total, Allmineral has supplied over 400 alljig jigging machines around the world, where they are used to efficiently sort not only slag, but also coal, ore, gravel, sand, crushed stone and recycling materials.