Refractory Requirements Research Articles

Radiation control of refractories

X-ray and electron-x-ray methods of control are useful for detecting the main types of defects in refractories for MNLZ (continuous casting). The sensitivity of the control corresponds to the requirements of refractories. X-ray control of refractories may be carried out on the x-ray-television introscope RI-60TK and the electron-x-ray equipment ERGA-03. As a source of radiation we can use the RAP-150/300 apparatus.

Refractories for coke oven doors

The main requirements of refractories for the doors of coke ovens are enhanced strength and thermal-shock resistance, and a reduced thermal conductivity. The use of chamotte articles due to lamination leads to scaling and spalling, and increases the gas permeability of the structure and causes rapid wearing. The resistance of the brick is reduced with an increase in the volume of the coking chamber, and this equals 1.5–2 years. In recent years a start has been made with the use of block concrete linings for the doors of coking ovens on the basis of concrete containing chamotte fillers and aluminous cements. The resistance of concrete blocks reaches 4–5 years or more. With block linings there is a reduction in the number of joints, ensuring mechanization of the installation and demolition of the lining, and a reduction in the time spent on lining operations. Two types of Soviet designs are used for the doors of coke ovens with block linings. The most promising is the nonreinforced lining with removable components, permitting independent changing of the blocks, and repeated use. Abroad, research is going on into reinforcement of blocks with metal fibers of special composition and the use of fused quartz for preparing the blocks.

Dense powder from beneficiated dolomites for producing tar-bonded dolomite refractories

Flotation-beneficiated dolomites from the Novotroitsk and Elenovsk deposits consist of high-quality (in terms of chemical composition) materials containing less than 0.65% SiO2 and 0.4% sesquioxide. The particularly low concentration of impurity oxides is a feature of the beneficiated Elenovsk dolomite. The apparent density of the pellet is more than 3 g/cm3 which is achieved after sintering by additional grinding of the beneficiated dolomite, pelletizing the milled product, and burning the pellets at a temperature of at least 1700°C. The beneficiated Novotroitsk dolomite is sintered better than the Elenovsk; this is due to its fine grained crystalline structure and its concentration of impurity oxides. The beneficiated calcined dolomites from the Novotroitsk and Elenovsk deposits having an apparent density of more than 3 g/cm3 are products suitable for making high-quality tar-bonded dolomite and tarbonded dolomite-magnesite products satisfying the requirements of refractories for converters. It would be desirable to carry out industrial experiments on the beneficiation of dolomites (producing a batch of at least 1000 tons) followed by burning the dolomite, preparation of tar-bonded dolomite refractories, and testing them in service.

Slide Gate Nozzle Tests on 1 Net Ton and 280 Net Ton Ladles

In test No. 4, it was demonstrated that the slide gate nozzle can be used to control teeming of 280 NT ladles. Several refinements need to be developed before it can be used for daily operation. Refractory requirements were not completely determined, although it appears that high purity alumina slide plates will be satisfactory and that zircon plates are not satisfactory for 280 NT ladles. Evaluation of collector nozzle design was not completed. The fireclay body with an alumina insert is satisfactory but it may be possible to use a less expensive arrangement. Preliminary economic studies indicated comparable costs with stopper rod systems.

Growth Pattern of Steel Plant Refractories in India

The growth of steel plant refractories which follows closely the iron and steel industry has been traced for the past one and half decades and the gradual fall in refractory consumption per ton of ingot steel produced in India during the same period has been indicated. Based on the present consumption rate and estimate for the future as well as the projected targets for iron and steel industry upto the end of the fourth five year plan, the refractory requirements and the course of action necessary to meet the demand have been suggested. The role of National Metallurgical Laboratory in catering to the needs of the industry has been mentioned briefly.

REFRACTORY REQUIREMENTS FOR OIL REFINING

Aside from boiler settings and such minor uses as fullers earth revivifying furnaces and sludge acid recovery plants, the main use for refractories in oil refineries is in fire still settings. With the shell type stills which were almost exclusively used in the past, service conditions are not severe enough to require anything more refractory than the best quality No. 1 fire brick, but some of the tube type cracking stills recently introduced are much more severe in their refractory requirements.

METALLURGICAL REQUIREMENTS OF REFRACTORIES IN COPPER SMELTING AND REFINING1

The requirements of refractories in the copper industry may be classed as follows: 1Resistance to temperatures 2Resistance to chemical action 3Ability to withstand sudden temperature changes 4Minimum absorption of slag and metal 5Absence of manufacturing defects.

REQUIREMENTS OF REFRACTORIES FOR ELECTRIC FURNACES

This article is essentially a survey, giving, however, not generalized statements, but a definite discussion of the refractories problems now existing in the important electric furnace processes. After summarizing some of the general refractory requirements of electric furnace work, the author discusses the specific conditions and refractory requirements in steel, iron, and non-ferrous metal melting, smelting furnaces for producing iron, ferro-alloys and calcium carbide, anti in furnaces for melting refractory materials. The article closes with a summary of outstanding present developments. Varied conditions probably make an ideal, universal refractory almost impossible of attainment. The relatively cheap refractories standardized in fuel-fired furnaces have been very largely used in electric furnaces. There is, however, a growing use for specialized “super-refractories,” even at greatly increased cost, that will stand various especially severe conditions in certain kinds of work. Important recent developments are higher firing temperatures, the use of high aluminous fire clays, and increased experimental work on fused refractories. The commercial production of sufficiently high firing temperatures, and the development of satisfactory bonds for special refractories are at present perplexing problems.