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The production and use of refractories using waste-free technology is one of the main tasks for increasing the efficiency of the refractories industry and repair services in metallurgical combines.The present authors developed a waste-free, ecologically safe* method for the production and use of periclase-carbon articles for lining electric steelsmelting furnaces.The starting materials consisted of various sintered periclase powders, carbon containing materials --Taiginsk and Zaval'evsk graphites , organic bond, and also antioxidant additive.The centrifugal mixer was loaded with the starting materials which were mixed for 5-10 min and fed to the presses.The body was nondusting, did not stick to the plungers, and did not emit harmful organic compounds.The composition of the periclase-carbon articles grade PUEP,II6 in % was: sintered periclase powder 65-67, organic bond 9-12, graphite 13-16, and antioxidant 9-12.The articles were pressed at 140-160 N/mm 2. The dimensions of the products were 386 • 154 x 85 x 75 mm, and the mass 13.5 kg.The articles were made according to the press-pallet method; immediately after pressing they were stacked on the pallet using a metal base in six courses interleaven; the mass of one pallet was 1.2 ton. One pallet~passed through the tunnel drier at 180~(12-16 h), the others were held between the tunnel kilns at a temperature of about 40~ directed to the finished goods warehouse, without sorting, tied with metal strapping, and delivered to the customer.The price of 1 tonne of products was 168 rubles (TU 14.8.506-86, modification No. 2).The material formed as shaping loss after crushing to fractions finer than 5 mm can be delivered to the users as prepared ramming bodies, or with additions of lignosulfonate used again for pressing periclase-carbon articles.The properties of the PUEP-II6 articles are shown in Table i.The periclase-carbon articles PUEP-II6 have strengths that are quite adequate for transportation, a low porosity, high refractoriness under load (even without drying) increased thermal conductivity, and high magnetic susceptibility.They are practically gas impermeab~.The properties of periclase-carbon articles are affected by the pressing force (Fig. i). With an increase from 40 to 150 N/mm 2 the compressive strength of the articles is doubled, and the dynamic elasticity modulus is trebled.The influence of the drying parameters on the strength of the goods is shown in Fig. 2; the maximum strength is possessed by articles after drying at 80~ (i day).In practice the goods should be dried at 60-120~ for 16-20 h. Drying at above i20~ and for more than a day leads to a fall in the strength of the goods as a result of the evaporation of the volatiles and destruction of the bond, and also it increases the mass loss during calcination by about 3%.The area of change of the dynamic modulus during heating to 1450~ and cooling of the articles, representing the work of destruction, in articles without drying is 1o5 times less *Content of harmful substances in the air in working sites ne...

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The factors responsible for the failure of blow plugs for steel ladles used in extra furnace steelmaking technology are considered. Results of a structural study of refractories based on electrofused corundum, crystalline silicon, and artificial graphite are reported. To improve the properties of corundum-carbon refractories, the sintering temperature should be increased to 1600°C.Blow plugs for steel ladles used in extra furnace steelmaking technology are fabricated from high-quality refractory materials. Under service conditions, the plugs are exposed to a number of factors that are capable of accelerating the wear of the plugs and finally lead to their failure. These factors are: inlet slit channels through which an inert gas is injected. The ingress of molten metal may cause irreparable damage to the blow facility;high temperature gradients and, consequently, high thermal stresses in the refractory material because of the cooling due to the injected gas; enhanced risk of erosion failure of the gas channel walls exposed to the gas jet and molten metal at the channel outlet in the steel ladle.In practice, blow facilities are subjected to a faster wear than nozzle blocks or ladle bottom lining and therefore require frequent replacement. Enhancing the service life of blow facilities is a challenging task; for its satisfactory solution, one will need innovative steps to be taken in both engineering design and advanced refractory materials. A step in this direction may be an adequate assessment of the physical, chemical, and mechanical properties of refractory materials potentially suitable for fabrication of blow facilities.