Reducing agents in the blast furnace process
In the last ten years, the blast furnace process at both Austrian sites (Linz and Donawitz) underwent significant further development. By expanding the injection technology, up to seven alternative reducing agents can now be used in the blast furnace; this represents a global benchmark. Valuable primary resources, such as coking coal and oil are conserved and replaced by secondary raw materials, such as, crude tar, coke gas, or used plastic.
The blast furnace process offers substantial potential with regard to conservation of primary raw materials on one hand and, on the other, in the recycling of used materials, as is demonstrated by the utilization of shredded used plastic. Besides, the diverse mix of input materials enables us to react flexibly to the fluctuating availability of input materials and to changing statutory provisions with regard to utilization of scrap material recycling and CO2 emissions.
Replacement of the alloy ferromolybdenum
A process developed in the steel mill in Uddeholms, Sweden, provides a contribution to resource conservation and cost optimization. Instead of the commonly used alloy ferromolybdenum, molybdenum trioxide and mill scale, which occurs in the plant as waste material, are used to retain the desired characteristics of steel. Molybdenum trioxide is an upstream product in the manufacture of ferromolybdenum.
Uddeholms has developed a completely new process in which one step in the production of molybdenum can be omitted. This newly developed process protects the environment along the entire production chain through energy and raw materials savings and is also economically attractive.
upcop – upgrading coal and powder injection
In the Group’s upcop project, a special sifting process has been developed for inferior-quality coal. This process extracts good-quality coal, which is used in the coking plant in Linz. The sifted portion of the coal has been used as injection coal in the blast furnace in Donawitz; from the end of 2014 on, it will also be used in the blast furnace in Linz. This process makes a significant contribution to the efficient use of raw materials, as it enables inferior-quality coal to be utilized completely.
ULCOS: Ultra-low carbon dioxide steelmaking
The objective of ULCOS is to significantly lower the CO2 emissions generated during the production of steel compared to the most effective technologies available today. New processes are being developed to this end, however, they will only reach industrial maturity in the future. 48 companies and organizations from 15 European countries, including voestalpine and other leading EU steel companies have formed a consortium.
(www.ulcos.org)
Production of iron oxide
Each year, approximately 90,000 m3 of pickling products accumulate from the hydrochloric acid pickling processes conducted by voestalpine Stahl GmbH. Two regeneration plants that employ spray roasting technology recycle more than 99% of the hydrochloric acid; iron oxide is generated as a by-product of this operation. The regeneration process was enhanced to the point that over 85% of the iron oxide is of high purity–a form suitable for the production of ferrites, which are used in the electronics industry. Any regenerated hydrochloric acid is returned to the pickling process.
With annual production of approximately 18,000 tons, voestalpine Stahl GmbH is Europe’s largest manufacturer of high purity iron oxide.
Recovery of metals from slag
Growing environmental awareness and the rising cost of metal make the efficient recovery of metals from slag both important and prudent. In collaboration with institutes at the Leoben University of Mining and Metallurgy, voestalpine is pursuing the development and optimization of processes for the recycling of metalliferous by-products. By-products containing significant quantities of valuable metals, such as zinc, lead, and copper, are especially promising.
Chrome (VI)-free pretreatment of steel strip
By the year 2000, voestalpine was already shifting to chrome-free production processes for coil-coated plates; since 2005, the surface treatment of hot-dip galvanized plate is also chrome (VI)-free.
voestalpine is the first steel manufacturer in the world whose entire product portfolio is free of coatings containing chrome-(VI) and whose production completely dispenses with a range of problematic materials.