Trip to the recycled of the steel

The factory in Saragossa of ArcelorMittal, first world-wide producer of steel, situates in the Technological Park of Recycled ‘López Soriano', on a surface of 220.000 m², of which 80.000 m² are covered. These modern installations have substituted to which previously had the company in the centre of Saragossa, to hardly 700 m of the Square of Pilar, and have supposed a near investment to the 140 million euros. For the transfer to the new plant took five years, concluding in 2007, but with this initiative ArcelorMittal has achieved to duplicate the production that had until then.

The new plant is divided in two big areas, the steelworks, that works with scrap of national origin to 100%, and the zone of laminación, that converts the semiproducto or palanquilla in a product finished.

This plant of ArcelorMittal characterises by his high degree of automation, that allows him, in addition to speeding up his productive processes, incidir in his aim of “0 incidents”. Besides, they are installations that show a big environingingmental worry, working with intensity in the reduction of the broadcasts of CO₂.

The visit to the factory of ArcelorMittal in Saragossa initiated in the tank of scrap, with capacity for 35.000 tonnes of material (the annual consumption of this plant is between the 600.000 and 800.000 tonnes).

Before going in in this tank, the scrap has to fulfil with a series of requests of hygiene like that it do not include elements that can produce explosions (enclosed tanks…), the absence of dangerous and flammable materials and be free of pollution. Also it has to be free of barren elements no ferric and properly separate and classified to facilitate so much his storage in the park of scrap of the steelworks like his back manipulation.

The surveillance of the entrance of scrap in the steelworks for his recycling realises through a sophisticated system of detection radiológica, of dangerous materials, improper, etc., with which guarantees the hygiene of the process.

Once classified the scrap, by means of a basket of 95 tonnes of capacity does a selection of the material, of agreement to his different qualities. By means of big cranes carries elevated the basket until the top of the oven, a “enormous “ cazuela”, where deposits the residue. For each cycle of fusion need around 135 tonnes of material, by what is usual to employ two loads by cycle.

In the case of the steelworks of ArcelorMittal Saragossa works with an electrical oven that incorporates a gigantic electrode of graphite (this plant has hired a power of 100 MW). The electrical oven was a process that used initially for the manufacture of special steels, but that in the actuality facilitates the massive recycling of scrap to produce any type of steel, with the only limit of the quality of the prime matter.

In Spain there are 21 steelworks of electrical oven, that produce 75% of the total steel manufactured in our country and consume around 90% of the scrap that the sector uses like prime matter. The remaining 10% uses in the 2 steelworks LD that produce steel basically from mineral of ironinging, using a true percentage of scrap with effect refrigerante.

The process of fusion, for which reach temperatures in the oven of 1.600 °C and that requires cycles of 1 hour roughly, complete with the oxidation of some impurities to delete them, helped by the injection of oxygen. The process involves the learning of a costra of oxides, that avoids the losses of power and protects the liquid steel. This costra withdraws later, forming the designated slag, that has distinct applications as for example his use like sustrato for road. After the fusion, the steel happens to a second smaller oven, in which it adjusts the composition of the multiple aleantes that determine each type of steel.

Like another proof more than his high environingingmental commitment, the factory of Saragossa has a modern installation of purification of smokes, that from different filters allows to separate material like the zinc for his back valorisation.

To continuation solidifies the liquid steel in the process of colada. It can colar the steel on moulds with the form of the piece that wants to manufacture (steel moldeado) or on lingoteras for his back transformation by deformation in hot (laminación, forges…). And there is a third method of colada, the most modern and that in Spain represents 90%, designated colada continuous, that consists in colar the steel in an open background mould, whose transversal section has the form that wishes obtain, and of the that goes extracting of continuous way the steel solidified in palanquillas, round, planchones… This last case is precisely the one who employs ArcelorMittal Saragossa, that solidifies the liquid steel by means of water and that cuts the palanquillas by means of sopletes of oxygen.

Once that the palanquillas recess his temperature until the 400 °C roughly, already can be manipulated through cranes magnetised, to happen to the following process of laminación.

Finally, the semiproductos obtained through the colada laminan in hot, doing happen the material between two rollers in a continuous process of deformation. This technician of laminación allows to obtain products of constant section (profiles, bars, alambrón…) and flat product (sheets, coils). In the case of ArcelorMittal Saragossa, one of his more known products are the sections that compose the towers of high tension.

The product finished raisin to the warehouse, smart to be loaded in any of the numerous trucks that arrive daily to this factory. All the articles have his corresponding certificate of quality and, thanks to a system of codes, can follow to 100% his trazabilidad.

The visit concluded precisely in the laboratory that has ArcelorMittal in these installations, where analyse mechanical and chemically all the materials, of such form that can improve the process and attain products adjusted to the specific needs of each one of the customers.

In 2011 the Spanish steelworks recycled a total of 12,5 million tonnes of steel (ferric scrap), of which 7,7 million tonnes were of national origin and the remaining 4,8 million tonnes proceeded of the import.

These figures place to Spain like leader of the recycling in the EU, together with Italy. 75% of the steel manufactured in Spain is steel recycled, while the European average is of 50% and the world-wide average of 40%.

By his big capacity recicladora and the high technology of his steelworks, the industry siderúrgica Spaniard is in conditions to guarantee the recycling of all the scrap collected in our country. The sector siderúrgico closes the cycle of the recycling of the steel, more than duplicating the value added regarding the prime matter (ferric scrap).

The steel is the material that more recycles . In Spain, the industry siderúrgica recycles more steel that the sum of all the other metals, the glass, the paper and the together plastic and the global tax of recycling in our country surpasses already the aim of 90% fixed sectorialmente for 2050 to world-wide level.

At the end of his cycle of life collects and recycles the pertinent steel of the construction, the car, the appliances, the ships, the containers of hojalata… and practically the whole of the steel that use in very distinct products and applications.

The steel has a characteristic particular that facilitates his collected for the recycling: it is magnetic, so that with an electromagnet can be easily separated of the rest of the waste.

The collected of the steel for his recycling produces by very distinct roads: from the centres of transfer and the collected selective, to the collected on foot of street or the separation by magnets in dumps, among others.

To the simple of his recovery joins the big capacity recicladora of the industry siderúrgica that gives new life to the steel to transform again partly of a car, of a beam of a building, of a washing machine, of an aerogenerador, of a bicycle, in a tin, in a clip, in a spoon, in a screw…

And this cycle of recycling, thanks to that the steel is a permanent resource, is a cycle potentially endless, in which the industry siderúrgica recycles one and again the steel without loss of his quality and without hardly merma, in an eternal renacer. In fact at present it follows recycling steel manufactured 150 years ago.

The steel, as it signalled in presses conference, is the material second in trade, only by behind the oil, and the second also in volume (the first is the cement), consolidating as an indispensable element in the majority of products that surround us, from a small clip until the most modern aeroplanes, going through the revestimiento of the tyres, the nautics sector, the aerogeneradores, etc.

The industry siderúrgica Spaniard supposes 4,6% of the industrial GDP. With data of 2011, produced 15,5 million tonnes of gross steel (third European producer by volume after Germany and Italy); the apparent consumption of products siderúrgicos was of 13 million tonnes. The sector is netamente exporting -63% of the sales-, reaching 3,9% of the Spanish exports of goods.

Innovation, efficiency, sustainability and labour hygiene are principles that govern the strategy of the sector, that recognises like a fundamental actor of the new green economy. Each tonne produced comports roughly 4,5 euros in environingingmental investments. The industry realises an efficient use of the resources until taking advantage of almost 80% of the waste and by-products that generates in the process.

The sector siderúrgico characterises besides for being the greater logistical operator after the oil and his derivatives.

Unesid Is the business association of the Spanish siderurgy that agglutinates 46 companies, that employ to 60.000 people (direct employment and induced) –in addition to the 20.000 that take part in the recolección of scrap- and invoice in his group 14.000 million euros.