Service of chrome — Forsterite products in the vertical channels and roofs of slaggers and regenerators of open-hearth furnaces

Conclusions Following industrial testing of thermal-shock resistant chrome -forsterite refractories in 400 ton open-hearth furnaces we established that it is possible to use them completely for replacing magnesite — chromite products in the roofs of slaggers and regenerators, and chrome — magnesite products in the structure of vertical channels.The use of chrome-forsterite products in the structure of the roofs and the walls of the lower structure of open-hearth furnaces would reduce the consumption of magnesite — chromite and chrome — magnesite products and have a substantial saving effect.Translated from Ogneupory, No. 2, pp. 22–31, February, 1970.     

Differentiated use of refractories in blast-furnace hot blast stoves

Conclusions In the service of blast furnace hot blast stoves the lining and checkerwork fail in individual zones as the result of deformation of the refractories, formation of cracks, and chemical corrosion of the lining under the action of low-melting dust at high temperatures.It was shown that the deformation of aluminosilicate refractories depends not only upon temperature, load, and hold but also to a large degree upon the physicochemical properties of the parts, especially upon the composition and quantity of impurities.On the basis of an analysis of the service of refractories in hot blast stoves recommendations were developed on differentiated use of refractories in the different zones of the lining and checkerwork.For lining of the walls and the checkerwork of high-temperature hot blast stoves operating with a blast temperature up to 1300°C (temperature under the crown 1500–1550°C) the use of the following forms of refractories (GOST 20901-75) is recommended: 1550–1200°C temperature zone — type DV dinas parts; 1200–1100°C temperature zone — type MKV-72 mullite-corundum parts; 1100–900°C temperature zone — type ShV-42 chamotte parts; 900–700°C temperature zone — type ShV-37 chamotte parts; 700–400°C temperature zone — type ShV-28 chamotte parts.To line the lower portion of the combustion chamber mullite-corundum parts of types MK-80 to Technical Specification 14-8-405-82 or MKV-72 must be used.Lining of the crown, the inner wall of the combustion chamber, the hot blast lines, and the gas burners must be done with mortars corresponding to the types of refractories used (dinas and VT-1) with the addition of 10–12% orthophosphoric acid.Type MKRP-340 mullite-silica fiber parts to GOST 23619-79 and other fiber materials are recommended for use as the compensation gap filler up to temperatures of not higher than 1150°C, and asbestos-vermiculite plates to GOST 13450-68 in the up to 600°C temperature zone.The shell of the hot blast stove in the high temperature zone must be covered with thermal-insulation gunited concrete.Translated from Ogneupory, No. 7, pp. 44–50, July, 1986.     

Minimization of organic chemical load in direct dyes effluent using low cost adsorbents

The work is carried out to minimize the organic chemical load (unexhausted dye contents) in direct dyes effluent using low cost adsorbents. The studies are made with different direct dyes, i.e. Direct Red 28, Direct Yellow 12, Direct Orange 26 and Direct Blue 1 with various adsorbents. Three different bio/natural materials have been selected as adsorbents. These includes, Sugarcane bagasse pith (SB), Saw dust (SD)—the plant origin products, and Brick powder (BP)—a silica based material obtained from earth's crust on thermal heating. These substances are almost discarded waste products with the possibility of use as adsorbents. Experimental work for the dye removal from the effluent by activated charcoal (AC) has also been carried out and the results are compared with other adsorbents. The amount of unexhausted organic dye present in the effluent is measured as chemical oxygen demand (COD) before and after the treatment. Adsorbent Sugarcane bagasse pith shows good performance as compared to Saw dust and Brick powder. For understanding the behaviour of adsorbents Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) has also been carried out.     

Beneficiation technology for natural and caustic magnesite using the hydrochloric acid method

Conclusions A study was made of the solution kinetics in hydrochloric acid of natural magnesite and caustic magnesite dust extracted from the waste gases of rotary kilns. It is shown that the solution rate of caustic dust in cold acid (cold solution method) is 10–12 times higher than the rate for natural magnesite at 80–100°C (hot solution method) and hence the use of dust for obtaining a high purity product would substantially increase the output of the chemical beneficiation plant.In dissolving caustic dust, heating of the solvent (acid) and milling of the material to be dissolved are excluded. Working with cold acid facilitates the choice of chemically resistant equipment and improves working conditions.Chemical beneficiation of the dispersed caustic magnesite dust, including its solution in cold 12.5% HCl, precipitation of sesquioxides, filtration, hydrolysis, and washing of the calcium oxide will improve the highpurity finished product (98.2–99.1% MgO).Translated from Ogneupory, No. 7, pp. 14–18, July, 1980.     

Emission during the firing of chrome-magnesite products in tunnel kilns

Conclusions When chrome-magnesite products are fired in tunnel furnaces, the concentration in the effluent gas of dust is 110–150; of Cr₂O₃, 5–7; NO_x, 20–35; CO, 100–125; SO₂, 25–40; and SO₃, 30–70 mg/m³. The emission dust is finely dispersed. The average size of the particles of dust is 0.3, the minimum 0.05, and the maximum 1 m. There is no hydrogen sulfide, NO₂, or CrO₃ in the emission.Dust and nitrogen oxides are formed in the firing zone of the kiln. The formation of dust and NO₂ depends on the air-consumption coefficient.The use of the pipe-in-pipe type of ports does not provide good gas combustion. To improve the operation of the kiln and the combustion of the natural gas it is recommended that instead of the obsolescent tube-in-tube ports, the ports developed by the Eastern Institute of Refractories be installed since they have given good results in tests [7].To improve the scattering effect of the removal of dust in the existing equipment it is recommended that the height of the flue stacks be increased to 40–50 m.Translated from Ogneupory, No. 4, pp. 36–41, April, 1986.     

Pharmacokinetic Properties of Fibre Materials Modified by Co-Immobilization of Different Biologically Active Substances

The possibility of manufacturing dressings with a combined biological action by modifying fibre materials of different types with combined immobilization of an enzyme — protease C — and a polymeric antimicrobial — polyhexamethyleneguanidine hydrochloride or polyethyleneimine with glutaraldehyde — was demonstrated. It was shown that with respect to the maximum stability of the enzyme, the fibre materials used for immobilization of protease C together with PEI or PHMG are in the order: PCA > CG > CG—PE. It was found that fibre materials containing immobilized protease C and polyhexamethyleneguanidine hydrochloride or polyethyleneimine exhibit a higher level of activity than the native enzyme at pH 6-9 corresponding to the conditions of use.     

Technological bases for realizing the preparation of bulk-profiled yarns on LPM-15 modernized industrial lines

Conclusions A fundamentally new type of fibrous materials — bulk fibrillated yarns — can be produced on the basis of modernized LPM-15 lines.The significant possibilities for variation in the make-up of compositions make it possible to use essentially scrap secondary raw material or waste plastics. Prospectively, bulk fibrillated yarns can receive just as wide circulation as film-process fibrillated yarns from polypropylene or other polymers.Translated from Khimicheskie Volokna, No. 5, pp. 47–50, September–October, 1989.     

Optimizing the process of filtering spinning solutions

Conclusions The question of optimizing the spinning solution filtration process with respect to a production criterion — the maximum gain in commercial production (profit) — has been examined.It has been shown methodically and experimentally that attainment of the maximum yield of fibre of highest quality as a result of increasing the cleanness of the spinning solution is attended with a deviation from the maximum profit.A procedure has been worked out, and specific example given, for calculating the optimum values of the filtration surface and charge density for typical manufacturing situations. It is recommended to use this procedure in plants which produce viscose, acetate, nitron, or other fibres.Translated from Khimicheskie Volokna, No. 6, pp. 8–12, November–December, 1985.     

The service of regenerator checkers in open hearth furnaces

Summary An effective way of increasing the life of checkers is to increase the height of the structure made of chrome-magnesite brick to 10–12 courses. This reduces the average melting time, increases furnace output by 5–7%, and reduces the oil consumption by 7%.The dust settling on the refractory has a typically high content of iron oxides. At normal checker temperatures (not above 1400°C) the surface of the refractories forms friable, dusty deposits. With a rise in temperature in the regenerator the dust sinters, partly fuses, and sticks to the refractory. This cake is removed by blowing the checkers.Investigation of the refractories after service confirms that the phase changes,in the reaction layer of the brick, take place mainly owing to the action of iron oxides of the dust on the refractory. Fusing of firebrick is also intensified by oxides of iron contained in the dust.The mineral formation and destruction processes are greatly affected by the changing composition of the gaseous atmosphere, which is confirmed by the formation of mixed crystals of magnetite and haematite in the crusts and reaction zones of the refractory.Of the refractories tested in the checkers, the best was chrome—magnesite.To explain the possibility of increasing the life of checkers, experiments should be made using forsterite brick of high quality in the 15 top courses of the checkers using the Cowper system of building the checkers.     

The wear of magnesia refractories in electric furnaces for melting cast iron

Conclusions The wear of magnesia refractories, i. e., magnesite, perictase — spinel, and magnesite — chromite bricks and magnesite — phosphate mortar, in the walls of electric furnaces for melting cast iron is the result of the solution predominantly of the periclase crystals and to a lesser extent of the spinel in the lowbasicity ferrosilicate slag melt. Brick of the PShS type proved to be the most durable refractory. The use of high-alumina brick in the roof of the furnaces accelerates the wear of the magnesia bricks in the walls.To increase the durability of the lining of these furnaces trials should be carried out with an all-basic wall lining constructed of high-density PShSP-type brick on MF-1-type magnesite — phosphate mortar and a roof lining constructed of MKhS brick and the same mortar.Translated from Ogneupory, No. 4, pp. 44–49, April, 1976.     

Developing a rational method for returning dust extracted from rotary furnaces

Conclusions It is possible to introduce dust into the briquette for firing into grog in amounts of not more than 10–20% depending on the plasticity of the raw materials. It is possible to use clay-slip moistening to obtain higher strength briquettes.Short grinding of the dust in a vibromill improves the sintering, and increases the bonding capacity.Translated from Ogneupory, No. 6, pp. 41–45, June, 1968.     

Deformation properties of complex viscose yarns before and after relaxation in water

Conclusions The character of change in deformatic properties of complex viscose yarns — breaking load and elongation — as a function of the magnitude of the work of deformation to break has been established.The suggestion has been made that it is possible to use this dependence to evaluate yarn defectiveness.Translated from Khimicheskie Volokna, No. 6, pp. 43–45, November–December, 1986.     

Determining the maximum possible rates of single sided heating of refractories

Conclusions Tests on refractories on a special rig showed that the permitted heating rates on the hot face, without producing important changes in the engineering properties, are as follows: for dinas refractories 3 deg/min, magnesite 7.5 deg/min, and chrome — magnesite and magnesite — chromite up to 20 deg/min. These rates are greater than the calculated rates which may be due to the effect of structural heterogeneities in the product. However, the use of such heating rates for the refractories in the structure of heating units is possible after careful practical checking in industrial conditions.Translated from Ogneupory, No. 4, pp. 51–55, April, 1971.     

Study of the compatibility in the poly (vinyl-chloride) -poly (vinyl-alcohol) system

Summary Although poly (vinyl-chloride) — PVC — and poly (vinyl-alcohol) — PVA —mixtures are used in practice for coatings, containers, fibers, few studies are encounterd concerning their compatibility (7, 8).This paper establishes both the optimum compatibility ratio and the thermal behaviour of the mixtures.The compatibility study in solid state was realised using the methodes: optical microscopy, thermogravimetry, DSC, inverse gaschromatography and IR spectroscopy.     

Fire hazard properties of viscose fibre dusts

Conclusions The fractional composition of viscose fibre dust formed in the packaging division has been investigated.A quantitative determination of the combustible dust accuulated in the manufacturing packaging site has been carried out.It has beem shown that the viscose fibre dust fraction with a particle size less than 0.800 mm presents an explosion hazard, but the content of explosive dust does not exceed 6.1% of the total amount of dust. Dust which has not been separated into fractions presents no explosion hazard.To ensure safety from fire in viscose fibre packaging locations, it is necessary to use a mechanized dust-collection system.Translated from Khimicheskie Volokna, No. 6, pp. 44–45, November–December, 1989.     

Enhanced mass transfer at the rotating cylinder electrode. II. Development of roughness for solutions of decreasing concentration

The development of roughness at a rotating cylinder electrode has been investigated in the context of a metal recovery system — the ECO-CELL — where the solution concentration necessarily falls with time under batch processing. Roughness has been quantified using knurled cylinders and the use of thiourea as an additive has been considered. The development of a rough surface allows a reactor to recover metal at enhanced rates and the exploitation of this feature is discussed.     

Refractory concrete lining in open-hearth y-shaped pouring spouts

Conclusions The life of concrete linings in y-shaped pouring spouts is threefold that of chamotte linings. The main wear of the concrete lining is accounted for by the mechanical removal of the 8 to 10 mm thick slag — concrete contact layer during cleaning operations.The applicating of coatings of different composition substantially affects the structure of the concrete — slag contact layer.There was no difference in quality between metal poured through chamotte lined spouts and concrete — lined spouts.The use of concrete lining for y-shaped pouring spouts is warranted for technical and economic reasons. Further increase in the service life of this type of lining requires more testing and extensive adaption to industrial furnaces.     

Magnesia roof refractories with fused spinel in the batch

Conclusions Dense highly fired roof refractories based on sintered magnesite powder and electrofused aluminomagnesia spinel are characterized by high volume constancy and a 30–50% lower wear compared with ordinary periclase — spinel products in comparative tests in the roofs of 600 ton open-hearth furnaces working with the use of oxygen.The wear of magnesite — spinel refractories containing 20, 30, and 40% electrofused spinel in the batch during service in the roofs of open-hearth furnaces occurs by fusion.Translated from Ogneupory, No. 1, pp. 24–28, January, 1971.     

Manpower requirements for the fertilizer sector in sub-Saharan Africa

The manpower requirements are estimated for the fertilizer sector (production, marketing, and use) in sub-Saharan Africa from 1982/83 to 2002/3. The additional technical manpower requirements in sub-Saharan Africa over a 20-year period are about 15,917 persons for fertilizer production, 7959 for fertilizer marketing and 7958 for fertilizer use. It is estimated that, on the average, an additional 1592 persons will be required annually for the fertilizer sector. There is thus a need to establish —through both national and international organizations— appropriate fertilizer training facilities. This will relax serious manpower constraints in fertilizer sector development and thus will accelerate the contribution of fertilizer to economic growth in sub-Saharan Africa.     

Polarization-interference micromethod for the study of mutual diffusion in polymer systems

Summary A polarization-interference technique is developed for the study of mutual diffusion that is applicable to systems covering the whole concentration range from polymer — low-molecular-weight compound systems to polymer — oligomer systems. The technique is based on variations of the refraction index within the diffusion zone and is shown to have advantages over similar ones. Its accuracy in terms of wavelength is 0.04. The polybutadiene — dioctyl phtalate system is used to illustrate how the concentration distribution of the components is calculated.