In development of a method of production of unfired funnels for bottom pouring of steel it is necessary to solve two important problems involving selection of the type of binder and the heat treatment of the parts. In addition to reliable service properties unfired refractories must possess sufficient strength and water resistance.Unfired specimens may be strengthened by addition to the mixtures of binders hardening either cold or in heating to low temperatures (600~ max.). Recently phosphate binders have found the greatest use in production of unfired refractories and compounds [1, 2]. However, as experience shows, the high cost of such binders restricts their use, especially in the production of large-production parts. From this point of view spent acid electrolyte after electropolishing of tubes containing 51.9% HffO,, 21.1% H2SO4, 1.5% Fe z+ + Fe 3 § 0.6% Cr ~ § Ni 2 § and remainder water deserves attention. These acid wastes were used in this work as the phosphate binder.In conducting the laboratory investigations type Ch2 clay, chamotte with a water absorption of 9-10% produced from type Ch3 clay in the shaft kiln of Chasov Yar Refractory Combine, acid wastes with a density of 1.6 g/cm 3, and an aqueous solution of commercial lignosulfonates with a density of 1.08-1.12 g/cm 3 were used.It is known that in production of chamotte refractories a portion of the clay binder is added to the mixture together with a commercial lignosulfonate solution in the form of a heated slip. This provides obtaining of a dense and sufficiently strong unfired part. As the results of the laboratory investigations showed, it is desirable to add the spent electrolyte to the mixture by first preparing a clay slip with a density of 1.20-1.25 g/cm 3 using aqueous commercial lignosulfonate solution and then mixing it with spent electrolyte in a 1:1 volume ratio. The binder obtained is called a composite one [3].The investigations were made on specimens with a diameter and height of 25 nlm. The composition of the charge was 40% clay and 60% chamotte. The composite binder was used as the binder. The specimens were formed under a pressure of 40 Nlmm z, dried at 100-120~ to a constant weight, and heat treated in an electric resistance kiln according to the specified cycle. The compressive strength, water resistance,* open porosity, and apparent density were determined on the specimens. The properties of the specimens were determined the next day after heat treatment and cooling to the temperature of the *Property has not been standardized for refractories. Development of a special method and approval of it by the established procedure are necessary. Donetsk Metallurgical Institute. Chasov Yar Refractory Combine. Donetsk Metallurgical Plant.

The high multilayer charge in which refractory parts are fired is frequently the reason for formation of scrap and significant variations in the properties of refractories. In connection with this possibility of use of a roller kiln with single-layer firing for bottom pouring tubes was studied.In our country roller kilns are used primarily for firing of ceramic plates. Designs of such kilns are known [i, for example].At Konstantinovka Refractory Plant an SMK-158 roller kiln produced in Constructional Material Production Machinery Plant, Mogilev-Podol'skii has been built. The necessary changes and additions taking into consideration the product being fired have been introduced into the design of the roller kiln. The kiln includes a dryer. A single roller conveyer driven in sections by six drives was the means of movement. The rollers are driven on both sides by sprocket chains. To each roller is fastened a drive sprocket. The driving branch of the chain is located above the sprockets. Above the chain are located clamping strips. The rollers rotate in sleeves.The roller dryer consists of four similar sections with a length of 9 m each. Each section is a metal frame covered on the outside with steel plate. The lining of the walls, the hearth, and the roof is made of thermal insulation materials and chamotte brick. In the walls in a checkerboard arrangement on both sides there are hatches with doors for cleaning the hearth. Each section is equipped with 12 inj'ection burners located under the conveyer in checkerboard order. There is also a system for utilization of the stack gas heat, for which the manifold of each section is connected by an individual pipe with a controlling slide valve to the centrifugal fan removing the stack gases from the kiln. To remove the stack gases in the roof of each section there are exhaust manifolds connected by a pipe with a controlling slide valve to the common stack.The roller kiln consists of 24 3-m sections (positions) located on the frame of the roller conveyer. Between the sections there is a 20 mm gap filled with asbestos cord serving as a temperature joint. Rollers with a length of 2150 mm, a diameter of 32 mm, and a spacing of 70 mm pass through holes in the walls. The width of the kiln channel is 1150 mm and the height in the firing zone from the learth level to the peak of the roof 750 mm.To fire the kiln channel 157 gas injection burners are located over the whole length of the roller kiln in both sides in the walls in checkerboard order. In the heating and firing zones the burners are located above and below the roller conveyer. Under normal conditions the consumption of natural gas is ii0 m3/h. The stick gases are removed from the kiln through holes in the roof and directed to the dryer. The quantity of gases removed by positions of the kiln is regulated by slide gates.At the level of the hearth in each section there are four hatches, two on a side, in checkerboard order and two peepholes above the rollers to observe the working space.Lightweight and normal chamotte mater...

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At present, in the majority of steel plants of the country the upper structure of the walls of soaking pits is laid manually of 4-6 rows of chamotte brick and the remainder of the walls of large silica blocks and panels, the life of which is 8-12 months [i]. The edge is subject to mechanical action and thermal shocks, which leads to failure of the monolithic lining, a reduction in service lives to 2.5-3 months, and a sharp decline in sanitary and hygienic working conditions in the shop.There have been positive results of tests of edges of aluminosilicate concrete with a high alumina filler, high alumina cement* [2], and clay--phosphate binder [3].This article presents the results of production and testing of concrete parts with the use of production wastes [4].The experimental parts for the soaking pit wall edge were produced in the Khristoforov Refractory Block and Concrete Plant.Scrap from silicon carbide parts (86.68% SiC, 12.06% Si02, 0.15% C), bauxite (68.32% Al2Os, 3.58% Fe203), and commercial grade chamotte (31.15% AlaOs) were used as the filler of the concrete and high-alumina and alumina cements as the binder.The use of bauxites as fillers for refractory concrete is assumed to be possible with not more than 5% Fe203 in it.The original materials (with the exception of 20-0-mm fraction ground bauxite obtained from Borovichi Refractory Compound) were ground in an SM-741 jaw crusher and then in an OTsD-50 cone mill.The pulverized materials were separated into the 20-5-and 5-0-mm fractions (Table i). The mixture was mixed in a cement mixer.The parts were produced from plastic mixtures by the vibroforming method.+ The compositions of the mixtures are shown in Table 2.The mixtures were compacted with IV-47 deep vibrators a total of 12 parts of special configuration ( Fig. i) with a weight of 4.8 tons was prepared.

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