Periclase-carbon products for electric steel furnaces

Abstract

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...

Improvement and introduction of the lining of a gas-oxygen refining vessel

“…Emphasizing these refractories, it was taken into consideration that with a short life (about four times less than the life of PShPKh refractories) they are distinguished by high wear resistance under service conditions in converter production of steel with top oxygen and combined blowing, in electric steel melting production, and to some extent in vessels for argon-oxygen refining of metal [14][15][16][17][18].…”