Refractory recycling in iron and steel enterprises

Each of the major units of steel companies have scrap refractories production, mainly refractories are produced in routine repairs ,overhaul repair and removal of industrial furnaces process. Each year, 70% of refractory consumption is used in the steel industry. With the development of the global steel industry, especially in China's steel production with rate of 20% per year rapid growth has also increased the consumption of refractories. Therefore,how to achieve recycling refractories, has become an important aspect of the steel industry to achieve circular economy.
In terms of how effective use of waste refractories, the Japanese steel industry has done a lot of work in recent years, actively promote the study of refractory materials for reuse in various steel plants. For example, a steel company using refractories 4100 tons per month, of which 1,003 tons, representing 24% of refractories will become obsolete, the plant will be one of 750 tons used as paving material, with the rest as a resource recycling.

Their techniques in refractory recycling in terms of: (1) the disintegration of recovery respectively. A refractory used in the furnace due to the kind of the different parts and different. All kinds of used refractory mixed together, make the quality of management of refractory difficult to operate, so before making re-use, recycling must be classified. It Were recycled by the category of magnesia, alumina, and a carbon-based, no-carbon-based and so on. Further, mixing of dissimilar materials or iron, must by magnetic separation methods to separate them. Recycling the used refractory required to be crushed to 200mm ~ 400mm, shock used in the subsequent step of crushing, compression, or shear further crushed into a more manageable size of 20mm or less. For iron sheet scrap refractory, electromagnetic separation, with more than 12,000 Gauss magnetic strength, so that the particle size of the refractory material of the iron content of 5 ~ 10mm is reduced to 2% or less. Powder that crushed and reused after removal of iron as a raw material, the particle size is required to be managed separately. Grading is generally used to make a metal mesh sieve, mesh size according to need, a large mesh size in the above, the following small mesh size, continuous screening. Crushing, grinding and classification process should pay attention not to spread of dust, to seal the devices, recycled in the Dust. The collected dust may be added to the feedstock tile production landscape.(2) an appropriate proportion of the insertion of a new refractory raw materials. Inserted as a raw material, the particle diameter of 5 ~ 20mm, or 1 ~ 5mm, added at a ratio increases, the amount of water added should be increased, so that the porosity increases the durability of the product to be reduced. Given this tendency, the site should be noted that the addition ratio of recycling and use of the material. Wet spray stoppage particle size 1 ~ 5mm, dry spray particle size is less than 1mm stoppage. Material recycling is difficult to completely remove iron and impurities, such as adding more than 20% recycled material, and which due to the harmful effects of impurities contained in leaving less durable. A small amount of scrap refractory SiO2, CaO slag and other ingredients, can reacts with new materials which in Al2O3, MgO, SiC, generate low melting compound. Therefore, we must control the insertion of the amount of recycled material. Cascade scheme can be used, the use of advanced refractory after that, as the first intermediate refractory recycling, re-use as a lower refractory

China's steel enterprises, also re-utilization of the refractory actively explored. They will be more than 80% with the MgO-C as a raw material, with the same quality reproduction of the MgO-C; will use the ladle refractories and related the carbon products, all the re-production of slagging agent metallurgical materials; will use the magnesia-chrome brick reproduct to Gunning mixes.