Many years of experience in laboratory petrography at the Eastern Refractory Institute have shown that the method of production of inorganic materials (parts) represents a deliberate change in mineral (phase) composition and structure of the original components to obtain the optimum composition of properties of the finished products. In connection with this, the main production parameters must be based on the prediction petrographic data.This article considers petrochemical aspects of the production of forsterite-spinel refractories from carbon ferrochrome slags. The use of the lattermakes it possible to significantly broaden the raw material base of forsterite-spinel refractories, thereby having reduced the significant shortage of magnesia raw material, and to provide a change in the production of carbon ferrochrome to a waste-free method. In dddition, forsterite-spinel refractories from these slags may be used as possible replacements for scarce and expensive magnesia-spinellide parts,The object of the investigation was the waste carbon ferrochrome slags of Serov Ferroalloy Plant and Chelyabinsk Electrometallurgical Combine. The slags are a byproduct of carbothermal reduction of Kempirsaisk chromite ore. Pervoural and Bakal quartzites are used as the fluxing addition and the reducing agent is carbon (coke).During electric arc melting in the ore melting furnace chromium and iron are reduced to ferrochrome and the difficult to reduce oxides of the charge are converted to a refractory magnesia-aluminosilicate slag.The results of investigations of carbon ferrochrome slags at the Chelyabinsk Electrometallurgical Combine [i] showed the presence in their composition of forsterite, merwinite, melilite, and chromespinellide, The increased merwinite and melilite content in the slags, caused by the addition to the charge of lime, significantly reduced their refractoriness and practically eliminated the use of them as a refractory material.It has been noted [2] that alumina has a negative influence on the properties of forsterite refractories since spinel forms low-melting eutecticswith forsterite. However, both in the USSR and abroad there are data on the production of forsterite-spinel refractory materials and parts from the slags of carbon and foundry ferrochrome* [3][4][5][6][7][8]. The possibility has also been shown of the use of foundry and carbon ferrochrome slag as a filler for heat resistant concretes [9][10][11]. However, the slag filler had insufficiently high thermomechanical properties as the result of the significant (up to 55%) content of comparatively low-melting glassy phase.At present in connection with the shortage of magnesia materials there has been a sharp increase in interest in investigation and utilization of forsterite-spinel slags [12][13][14][15][16][17] but the mineral composition of the ferroalloy slags has been insufficiently studied. The quantity of periclase added to them to increase the refractory properties of the parts has not been based on the actual phase and chemical compositions of...

Magnesia-silicate rocks of different portions of chromite ores of Kempirsaisk massif in service at present are suitable for production of refractories [1][2][3][4]. We have investigated the properties of the dunite-serpentinite rock of the newly explored Poiskovoe chromite deposit of the Kempirsaisk region for the purpose of establishing of the possibility of use of it as a raw material for production of forsterite refractories and the development of a no-waste method of processing of chromite ores. A bulk sample of dunite-serpentinite rock taken from the core of a bore hole in detailed exploration of the deposit was investigated.The rock consisted of apodunite serpentinite (42%),* serpentinized dunite (17.5%), dunite (22.0%), peridotite (12.5%), and dunite-peridotite (6%).The chemical compositions of?the varieties of dunite rock are shown in Table i. All of the varieties of the investigated rock are stable in chemical composition and similar to Solov'evogorsk dunite, which is used for production of magnesia-silicate refractories.However, in comparison with Solov'evogorsk dunite, the investigated varieties are characterized by increased weight quantities of CaO (from 0.43 to 0.70%) and SiO 2 (from 35.10 to 36.8%).The increased SiO 2 content in the investigated rock leads to a decrease in the silicate modulus and some reduction in the refractoriness of the material.The refractoriness of the varieties of rock varies from 1670 to 1710~ and the refractoriness of the average sample is 1700~On the derivatogram of the dunite-serpentinite rock (Fig. I) there are observed three endothermal effects, at ii0, 400, and 700~ and two exothermal, at 810 and I160~ The endothermal effect at II0~ corresponds to removal of the adsorbed water and the effect at 400~ is caused by dehydration of brucite (about i0 wt.% brucite in the sample).The very intense endothermal effect at 700~ is caused by failure of the serpentine lattice in removal of the constitution water (up to 9%) and formation of amorphous metaserpentine as a new primary phase.The exothermal effect at 810~ is caused by rearrangement of the structure of metaserpentine and decomposition of it into forsterite and clinoenstatite:3MgO.2SiO~ ~2MgO'SiO2+MgO.Si02.The form of the endothermal effect on the DTA curve and the simultaneous loss of weight occurring as a jump on the DTG curve apparently makes it possible to consider this form of serpentine as a material with a defective structure.On the basis of thermogravimetric analysis it may be concluded that in decomposition of serpentine x-ray-amorphous phases of forsterite and enstatite are formed with subsequent crystallization of them (exothermal effect at I160~The above described endothermal and exothermal effects are characteristic of Solov'evogorsk dunlte'. *Here and subsequently wt.% is shown for chemical composition and vol.% for phase. tYu. E. Kuperman, Phase and Structure Transformations of Solov'

At'present in a number of steel plants of the country aluminosilicate parts and quickhardening silica compounds are being used for lining continuous casting machine tundishes.At New Lipetsk Metallurgical Combine cast compounds of periclase-chromite composition have found use. The life of monolithic silica linings is two or three pourings. Tundishes lined with aluminosilicate parts have a life of two to four pourings but the work for replacing the lining involves significant expenditures of time. The use of periclase-chromite compound ) with a tundish lining life of five or six pourings under the conditions of casting steel at New Lipetsk Metallurgical Combine satisfies the requirements of metallurgical engineers. However, the introduction of periclase-chromite compound is economically irrational.For the purpose of development of a waste-free method and composite use of raw material waste of concentration of Kempirsaisk chrome ores for preparation of monolithic forsteritepericlase tundish linings were studied. At present the concentration wastes are delivered to the dump and are not used in production.In mineral compositon the waste of concentration of Kempirsaisk chrome ore are a duniteserpentine rock containing (wt. %) 46-47 MgO, 28-30 SiO2, 8-10 Cr203, i.i AI203, and 8-9 Fe203 with ~mcalc of 14-16%. The chemical and mineral compositions of these wastes are similar to those of Solov'evogorsk dunite [I].The concentration waste was fired in a refractory production rotary kiln of Nizhnii Tagil Metallurgical Combine at 1470-1490~The open porosity of the fired product was from 8.6 to 12.3% and there was practically no dust fraction. The mineral composition of the fired waste includes* 60 for sterite, 15 chrome-spinellide, i0 magnetite, and 15 glassy phase of clinoenstatite composition.A forsterite-periclase compound possessing sufficient plasticity and reduced adhesiveness to the action of slags and metal was produced from fired concentration waste ground to the 3-0 mm fraction. The characteristics of the forsterite-periclase compound were (wt. %) 48.8 MgO, 29.8 SiO 2, 4.7 AI=O3, I.i CaO, &mcalc 1.7% bulk density 1.8 g/cm 3, and refractoriness greater than 1750~The grain size distribution of the compound was 5% coarser than 3 mm fraction, 13% 3-2 mm, 29% 2-1 mm, 20% i-0.5 mm, and 33% finer than 0.5 mm.The experimental forsterite-periclase compounds were tested in poured monolithic tundish linings in No. 2 Oxygen Converter Shop of New Liptesk Metallurgical Combine. The cast monolithic linings were preparaed in accordance with the technical instructions in effect in the plant with the use of water glass as a binder and of a hardener.Petrographic investigations and the results of x-ray diffraction analysis of the products of interaction of the hardener with the water glass make it possible to distinguish three stages in the process of formation of the binder strength [2]. The first stage is related to adsorption of the water glass on the hardener particles, as the result of which the density and viscosity of the composi...

Exhaustion of deposits of ore and nonore minerals, the increase in costs for mineral raw materials, and increasing ecological problems have created an increasing interest in recent years in secondary resources, composite processing of raw material, and the development and introduction of low-waste and waste-free methods.The use of secondary resources makes it possible to solve problems of providing raw materials, to reduce costs for their extraction and processing, and to reduce industrial discharges into the atmosphere and hydrosphere. In addition, processing of spent materials accelerates recultivation of disturbed lands and return of them to agriculture. These are obvious advantages of use of secondary resources.For production of refractories there is interest in metallurgical industry wastes, particularly in slags formed in production of ferroalloys, which at present in many plants are shipped to the slag dump.We will present the results of a technical, economic, and ecological evaluation of methods of production of periclase-spinellide-forsterite refractories with use of magnesiasilicate slags of Serov Ferroalloy Plant, of production of high-alumina cement and dry concrete mixtues and compounds from Klyuchevsk Ferroalloy Plant, and of production of periclasechromite unfired ladle parts with use of steel plat refractory scrap.The slags formed in melting of high-carbon ferrochrome at Serov Ferroalloy Plant have a magnesia-silicate composition and include forsterite (65%), aluminomagnesia spinel (24%), glassy phase of melilite composition (5%), and ferrochrome (6%). The refractoriness of the slags is 1700~This indicates the desirability of their use as raw material for magnesia refractories [i].In Eastern Refractory Institute a method of production of periclase-spinellide-forsterite (PShF) parts, forsterite-spinellide (FSh) refractories, and unfired periclase-spinellide (PShBS) and forsterite-spinellide (FShBS) nozzles and inserts ((PShBV, FShBV) has been developed [2,3]. The experimental lots of PShF parts were produced at Panteleimonovka Refractory Plant.Tests of PShF parts in the lining of an anodic furnace of Kyshtym Electrolytic Copper Plant showed life of them equal to that of chromite-periclase parts. Forsterite-spinellide refractories (FSh) and steel pouring nozzles (FShBS) were prepared at Magnesite Compound using high-carbon ferrochrome slag with addition of sintered periclase powder to eliminate the negative influence of the glassy phase of the slag. Therefore the positive results of tests of forsterite-spinellide parts with use of Serov Ferroalloy Plant magnesia-silicate slags in different steel production equipment indicates that the refractories developed are at least as good as chromite-periclase parts and in a number of cases exceed them in life.All-Union Refractory Institute.