Dunites from the Kytlymsk (lovsk) deposits, which in mineral composition are actually olivine rock [i], are of substantial interest as a raw material for magnesia--silicate refractories.Using these dunites would contribute to the extension of the raw-material base for the production of forsterite articles and would improve their quality.The main physicochemical, thermal, and other properties of these dunites were studied previously [2][3][4]. The studies showed that the use for the manufacture of forsterite refractories of dunites with a low degree of serpentinization, and hence with a low loss on calcination, yields high-grade articles without preliminary calcination of the raw materials.A project was developed for a production schedule for forsterite articles from unca!-cined Kytlymsk dunites in the refractories division of the Nizhnetagilsk metallurgical combine [3]. Separate batches of industrial specimens of forsterite goods which fully met the requirements of GOST 14832-79 were made.This article gives the results of industrial tests in the lining of heating units at the Verkh-lsetsk factory, using experimental forsterite articles that were made without precalcining the raw materials.The test batch weighing i0 tons was made at the experimental factory of the East Institute of Refractories using industrial samples of Kytlymsk dunites supplied by the planning office of Uralgeologiya~The output of articles measuring 230 • 115 x 65 mm was done in accordance with the technological schedules [3]. The articles satisfied the demands of GOST 14832-79 (Table i).The goods were tested in the overflow (pouring) and main ladles of the electric furnaces, and also in the "false" walls of the slag chamber of the open-hearth furnace in the steel melting shop.When the tests were being carried out in the DSP-25 electric furnace, transformer steel was being melted.The pouring process consisted of the following: liquid metal was poured from the furnace into the overflow (20-ton capacity) and partly in the main (30-ton capacity) ladles; then the metal was poured from the overflow ladle into the main one; since a layer of synthetic slag forms in the main ladle on the surface of the metal with a basicity of from 1.7 to 2.6, then during passage through it metal jets were additionally cleaned to remove harmful impurities. The dwell-time of liquid metal in the overflow ladle was 15 min, and in the main ladle 40 min.The wear of the lining in the steel-pouring ladles is mainly due to the sudden thermal shocks, and also the chemical and erosive effects of the liquid metal and slago When the tests were done in the overflow ladle it was lined with experimental forsterite articles in only the two upper courses, and the remaining part w~th the chamotte refractories that are normally used. The life of the lining was 35 heats (average for the shop), and in this case the residual thickness of the experimental and chamotte articles came within the range 60-70 and 40-50 mm, respectively.The working layer of the lining of the main ladle was made wi...

At the NorthMining-BeneficiationCombine (NlVIBC) pellets are roasted in two imported machines (service life more than 6 years) and two home-produced OK-306 machines (service life more than 3 years). Their design features are shown in Fig. 1, together with the sites at which samples of slag and the liping were taken. The pellet-roasting regimes are characterized by the mean temperatures and pressures over the zones of the roasting machines (Fig. 2).During these investigations we observed "inverting" of the cone, leading to a temperature rise in the branch pipes of the return flow manifold and to fusion of the lining. .C:ooUng , Gas-ai~ chamber numbers H) above pellet layer; 1) in gas--air chambers; 2) above pellet layer; 3) total pressure.All-Union Institute of Refractories. North Min|ng-Beneflciation Combine. Translated from Ogneupory, No. 10, pp. 33-40, October, 1979. 0034-3102/79/0910-0621 $07.50 9 1980 Plenum Publishing Corporation 621 The following m a t e r i a l s a r e used for the lining of the home-produced machines: high-alumina MKO-72 and MLO-62 artifacts, ShB-1 chamotte brick for laying the roasting, recuperation, and I cooling zones; VGL-1.3, ShLB-1.3, and SkLB-0.4 heat-insulating brick, kaolin wool, and heat-insulating gunite concrete, developed by the E a s t e r n Institute of R e f r a c t o r i e s (30% of M500 alumina cement, 30% of chamotte filler, and 40% of chrysotile asbestos of 7-450 brand); the t e m p e r a t u r e of the lining during use reaches 1000~The concrete is used for gtmiting the forward flow manifold and the branch pipes to the precombustion c h a m b e r s . Heatinsulating m a t e r i a l s constitute up to 50?o of the lining volume.To investigate the physicochemical effect on the r e f r a c t o r y lining we determined the g r a i n -s i z e and chemical compositions of the dust and gases. The g a s e s (the combustion products of natural gas of the Shebelinsk deposit) contained 0~ CO, 0.2-0.6% CO2, and 19.75-20.8% 0 2. The dust content of the g a s e s was 1.31 k g / m S ; the m o i s t u r e content was 10 g / m 3 (under n o r m a l conditions).The m e a n -s i z e composition of the dust (broken pellets) was as follows: 1.1% of the --2/~m fraction, 18.2% 5-10/~m, 23.8% 10-20t~m, 21.50/o 20-40/~m, 8.7% 40-60/zm, 4.2% 6 0 -8 0~m , 2.6% 80-100/~m, 4.1% t o r y . The s t r u c t u r e of the slag is c h a r a c t e r i z e d by i s o m e t r i chematite grains, the size of which ranges f r o m 0.02 to 0.08 ram, and a vitreous substance (Fig. 4). Table i shows the phase composition of the mullite--corundum brick with slag.The l e a s t -a l t e r e d zone is yellowish, dense, and uniform. Microscopic examination r e v e a l s s e c t o r s of mullite and corundum aggregates and a porous binder. The mullite aggregates consist of dense intergrowths of c r y s t a l s ; the corundum aggregates a r e l e s s dense. The vitreous substance is distributed in the binder fairly uniformly, but predominant filling of the p o r e s is observed.The intermediate zone is m a c r ...

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