REFRACTORIES REVIEW: UNITECR '07 Snapshot
The 10th Unified International Technical Conference on Refractories (UNITECR) convened in Dresden, Germany, at the convention center on the banks of the Elbe River, September 18-21, 2007. The conference featured 875 attendees from 44 countries, 138 technical presentations in 32 sessions (such as Steelcasting, Unshaped Refractories, Raw Materials, Testing, etc.) and 55 exhibitors. Most attendees were from Germany (270), followed by the U.S. (60), France (54), Austria (52), Brazil (46), Japan (37), India (31) and China (30).
UNITECR ’07 President R. Schmid-Whitley, Ph.D., presided at the Opening Ceremony, noting that the European community has a population of 490 million people and is the world’s largest exporter of refractories. A. Trickett of the International Iron & Steel Institute reported that world steel production will continue to increase, which indicates a continuation of the good demand for the refractories that enable the steel industry to function.
G. Hirth of Schwenk Zement stated that the rate of refractory consumption in the cement industry is 650 gm/ton of clinker produced, with a world usage of about 1.3 million metric tons. He commented that the long delivery time of shaped refractories (bricks) is a current concern of cement companies.
Input MaterialsA panel discussion on Input Materials (i.e., raw materials, logistics, energy, human resources, etc.) attracted the largest attendance at the conference. A. Meier, Ph.D., noted that the refractories industry is globally less profitable than refractory-consuming industries (steel, cement, glass, etc.). Meier concluded that:
- China continues to be the biggest global supplier of refractory raw materials by far.
- Companies with upstream integration of raw materials will do best.
- Consolidation of the refractories industry will continue.
- China remains the most important strategic challenge.
M. Lauderbach indicated that while there is no shortage of bauxite or alumina, there is a shortage of processing capacity. The situation is not yet a crisis, but the time is rapidly approaching when more alumina processing capacity will be needed.
Steel-Related SessionsHalf of the papers presented at UNITECR’07 dealt with steel-related topics, which isn’t surprising since the steel industry consumes 60-75% of worldwide annual refractory production. The themes of some of the steel sessions were casting, pig iron, converters, ladles, MgO-C, and Al2O3-C-SiC composites. Many papers reported on the improvements-and the related successes-in the various steelmaking applications.
The binder in (and bonding of) carbon-containing refractories for steelmaking continues to receive attention, as indicated by papers on topics such as a new, friendly resin with coupled anti-oxidants; the impregnation of carbon refractory materials; the microstructure and properties of MgO-C bricks with catalytically activated resins; eco-friendly, smokeless alumina-SiC-C bricks; and a MgO-C self-flow shotcrete castable for hot repairs.
The refractories industry has continually provided better refractories for steelmaking, so it is not surprising that examples of various improvements were reported, including:
- An improved Al2O3-SiO2-SiC castable for an impeller used to stir hot metal during desulfurization resulted in 20-40% longer life and no catastrophic failures.
- The use of a low-cement Al2O3-MgO castable for gunning maintenance, along with operations changes, resulted in an increase in ladle lining life from 200 to 350+ heats.
- The addition of yttria to MgO-CaO mixes can decrease the sintering temperature and reduce the product cost.
Other TopicsAnother popular subject was unshaped/monolithic refractories (discussed in 20% of the papers) concerning applications like blast furnace troughs, converters and ladles, as well as raw materials, binders, particle sizing, property evaluation/improvement and more.
Work continues to provide new and improved chrome-free bricks for the cement industry. Several novel compositions that have shown promise for cement kilns were discussed, including MgAl2O4-SnO2, MgO-SnO2, and MgO with Mg2TiO4 and CaTiO3.
The latest advances in refractory technology include the increased development and use of nanomaterials, as indicated by papers on the carbon nanostructure matrix of slide-gate plates, B4C-carbon nanoparticles in MgO-C bricks, the preparation of spinel nanopowder, and the use of nano-alumina materials.
As a result of the raw materials concerns facing refractory manufacturers (increasing cost, quality, stability of supply, etc.), there is an increasing interest in and need for the recycling of used refractories. Magnesita reported that in Brazil, 70% of all refractories used in steelmaking are consumed in the process, which leaves 30% for disposal and/or recycling. The latest technology for the processing and reuse of used refractories was discussed in four papers.
With the ongoing interest of refractory users in saving energy and reducing associated costs, two sessions (eight papers) focused on insulating refractories. Topics included fiber products, direct-foaming alumina, alkali corrosion, ultralight material and wet gunning installation.