The Middle Devonian Zavadov deposit of dolomites is located in Ternopol Region. The reserves of categories A--B-E, are 13.2 million tons and of category C2 26.8 million tons [i]. The dolomites are of monolithic, mixed, banded, brecciated, and honeycombed varieties [1,2].Samples of the dolomite were taken by the Pravoberezh Geological Exploration Expedition of Kiev GRP from the northern and northeastern walls of the pit from the trench in the 0-14.5-m range (samples Nos. 1-4) and from the cores of drilled holes (samples Nos. 5-17).The expedition established that the northern wall of the pit is made up of pure dolomites. In the drilled holes together with comparatively pure varieties quite thick layers (up to 8 m) of argillites and argillitelike clays are observed. In external form the dolomite of all of the samples is dense rock, not stratified, and from light-gray to dark-gray in color with bluish or yellowish hues.The chemical analysis of the raw dolomite is 16.98-21.15%* MgO, 0.20-4.77% R203, and 0.50-11.80% SiO2. Samples Nos. I, 5, 8, 9, 12, 15, and 16 type DSM-I, samples Nos. 2-4 and 7 type DSM-2, and sample No. ii type DSM-3 to Industry Standard 14-84--82 for raw metallurgical dolomite. As the result of higher SiO2 content the remaining samples are substandard raw material. *Here and subsequently weight % is given for the chemical composition and volume % for the mineral. 04 I 6,40 I 1,72 21,12 [ 1,90 I 0,49 19,02 I 2,65 I 1,00 18,02 [ 8,32 [ 3,45 18,88 I 1,65 I 1,35 16,94 I 1,88 I 0,77 Fe20a (20@

Periclase refractories for mass utilization are made from natural magnesite powder obtained from the Satkinsk deposits. TNe production technology includes preparation of the powders of the required substance and grain-size composition, including their hydration, the preparation of the bodies, pressing, drying, and high-temperature firing. In enterprises of the "South Refractory State Production Association" for the preparation of magnesia refractories, together with the Satkinsk material they are making extensive use of imported (Korean) magneslte powder.In order to study the qualitative and service properties of the periclase articles made from Korean powder and employing existing equipment of the enterprises of South Refractory SPO (YuzhoRneupor) wehad to carry out the appropriate developments. On the basis of the laboratory and technological studies we developed standard documentation, and together with the engineering and technical staff of the Chasov Yar combine and the Panteleimonovsk refractories factory, produced industrial batches of refractories (200 and i000 tons). The production of the industrial batches was preceded by trial batches designed to specify more accurately the technological parameters.At the Panteleimonovsk factory the trial batch was made partly from Satkinsk magnesite powder (batch I), and totally from Korean (batch 2). The body was prepared in mixer runner mills with an addition of organic bond. The articles from batch i were pressed on the toggle press; from batch 2 on toggle and hydraulic presses. The properties of the trial batches after firing in tunnel kilns are shown in Table i, and there we also present data for articles shaped at the experimental factory of the Institute and fired together with the articles from the Panteleimonovsk factory. We noted an improvement in the quality of the bricks formed on the hydraulic presses, and also those fired at increased temperatures. Articles at the Panteleimonovsk factory were made on the periclase-chromite refractories line, in connection with which there was some contamination from chromium oxide in these products.These investigations showed the need to use finer powder milling and a high-temperature firing for articles, in accordance with the existing standards.Using the more rigid standard specifications we prepared an industrial batch of articles from batch No. i (T0 tons) and batch 2 (130 tons) on the production line for periclase-chromite refractories which with small batch volumes and poor cleaning of the line led to contamination of the periclase body with chromite powder. The presence of the chromite in amounts of 8% (4% Cr203) reduced the compressive strength of the fired bricks from 60 to 33 N/mm =.Korean magnesite powder contained 89.2-92.9% MgO and 1.37-2.28% CaO, and Satkinsk -88.5% MgO and 1.49% CaO.The characteristic of the body and the apparent density of the green bric~ are shown in Table 2. The green brick were fired in tunnel kilns at 1640-1660~ with a car-pushing interval of 1 h 20 min --i h 40 min. The properties of...