Lumakon

BÜCHEL G., MICHELBACH H.-P., GIERISCH D., BUHR A. - Almatis GmbH, Franfurkt, Germany

Modern bimodal or multimodal reactive aluminas contribute to the design of vibration and self flow castables giving excellent flow and physical and chemical properties. The main focus has been on the reduction of the amount of water, which is required to achieve the desired flow behaviour. Mechanical strength and thermo mechanical behaviour are considerably improved with decreasing water demand. However, such castables may often have a significant disadvantage - their high dilatancy. Castables with dilatant rheological behaviour need higher energy during mixing and therefore require appropriate mixing equipment. They may also be difficult to work with under normal on-site conditions. Therefore the focus of the recent developments has been on “easy workability” of high performance tabular and spinel castables. The new reactive aluminas E-SY 1000 and E-SY 2000 (with spinel) are multimodal reactive aluminas for non dilatant castables. Vibration or self flowing castables with E-SY aluminas show a soft mix consistency and do not require high energy mixing, even at low water demands. After the mixing, the castables can be easily placed with a shovel, a basic but often important property for on-site application. This presentation will discuss the properties of castables containing E-SY aluminas with special focus on the workability properties

SEGEĎA I. - Slovenské magnezitové závody, a. s. Jelšava, Slovakia

Takmer počas celej histórie jelšavského závodu tvorila výroba tehliarenských a oceliarenských slinkov hlavný výrobný program. Zmeny v technológii výroby ocele donútili aj našu a. s. prispôsobiť sa svetovému trendu. V roku 1993 začala SMZ Jelšava produkciu novej generácie netvarovaných žiaruvzdorných materiálov s ročnou produkciou 1 600 ton. Ročná produkcia v 2005 bola 52 000 ton, s perspektívou rastu. Vývoj nových produktov neustále pokračuje, snahou SMZ Jelšava je pokryť svojou produkciou v čo najširšej miere potreby sekundárnej metalurgie.

Almost all the history round of Jelsava´s work, formed mainly production schedule steelmaking and brickmaking sinter. Change of steel production occasioned our company to adapt production schedule to world-wide trends. In 1993 SMZ a. s. Jelsava began production of new generation of unshaped refractory materials with annual production 1 600 ton. Annual production in 2005 was 52 000 ton with perspective of growth. Development of new products is continual process, SMZ Jelsava´s aspiration is to cover with its production all needs of secondary metallyrgy.

BURYAN M., MASCHLER F. - LOI Thermprocess GmbH, Essen, Germany

Pro dosazeni specialnich elektromagnetickych vlastnosti plechu a pasu pro elektrotechniku je zapotrebi nekolika zihacich procesu. Prednaska se zabyva vykladem jednotlivych peci a jejich technologickeho ucelu ve vyrobnim schematu. Duraz bude kladen na nove konstrukcni prvky a utvareni pecni atmosfery, ktera hraje rozhodujici roli pro kvalitu zihaneho materialu. V neposledni rade budou probrany moznosti pro snizeni energeticke narocnosti tepelneho zpracovani.

To reach special electromagnetic properties of silicon steel strip or sheet several steps of heat treatment are necessary. This paper will discuss the basic design of each annealing furnace and its technological role in whole production process. It will be focused on new structural elements and controlling of process atmosphere, which is most important for excellent quality of annealed steel strip. Last but not least some possibilities to reduction of energy requirement of heat treatment will be mentioned.

BARAŃSKY J., WITEK J. – Instytut Materialów Ogniotrwałych, Gliwice, Poland 

The technology of refractory monolitic blocks with high mechanical properties and superior abrasion resistance was worked out and implemented in Institute of Refractory Materials. Such a products are characterized by excellent corrosion resistance against attack of scale generated during thermal processing of steel ingots and blooms and also high thermal shock resistance. Fundamental properties of this products are quoted below: Al2O3 content min. 55%, ZrO2 content min. 10%, crushing strength after firingat 1350°C min. 120 MPa, abrasion resistance at 1 000°C max. 0.04 g/cm2, thermal shock resistance (850°C/water) min. 20 changes. Worked out monolithic blocks were applied in heating zone of several pusher furnaces used for thermal processing of steel slabs and blooms where 12-18 months service life was confirmed (comparable service life was observed for lining made of fused Al2O3-ZrO2). It was confirmed that monolithic blocks were characterized by excellent application parameters in workong conditions of pusher furnaces at temperature 1 280-1 300 °C.

PÁVKOVÁ N. – Průmyslová keramika, spol. s r.o., Rájec-Jestřebí, Czech Republic 
FORMÁNEK J., KALINA J. – PKI Teplotechna spol. s r.o., Brno, Czech Republic

Přednáška popisuje výběr izolačních žárobetónú vhodných pro aplikace v pecích na výpal keramiky s ohledem na jejich surovinové složení a následné výsledné fyzikálně-mechanické vlastnosti. Podrobně si všímá problematiky mísení směsí a zpúsobú jejicj zabudování ve vztaku k možnému velkému rozptylu dosažených parametrú. Dále se věnuje zásadám navrhování vyzdívek z izolačních žárobetonú v keramických pecích a uvádí příklady nejběžnejších aplikací.

Lecture is focused on assortment of insulating castables, which are applicable for ceramic kilns considering their raw material base and physical and mechanical properties. Potential parameter dispersion in situ is thoroughly considered in relation to castable mixture processing and installation. Lining design policy is discussed presenting examples of the most common applications.

KARIČKOVÁ A., GIRMAN V., ŠTULRAJTER S. - U. S. Steel Košice, s.r.o., Slovakia

Postupné trendy vo vývoji žiaruvzdorných materiálov viedli aj k zmenám výmuroviek tepelných agregátov v spoločnosti USS Košice. Tieto zmeny sa týkali nielen úprav konštrukcie výmurovky, ale hlavne materiálovej skladby samotných žiaromateriálov. Cieľom týchto zmien bolo predovšetkým zvýšenie kvality aj v podobe zvýšenia výdržnosti. Toto zvýšenie má v konečnom dôsledku priaznivý efekt na zníženie celkovej spotreby žiaruvzdorného materiálu vzhľadom k množstvu vyrobenej ocele.

Progressive trends in development of the refractory materials led to the lining changes of thermal aggregates in the USS Kosice. These changes are related not only with the arrangement of the lining, but mainly with the refractory composition. The goal of these changes was to increase the quality and performance. This increasing has a favourable effect in reducing of the specific consumption of the refractory materials.

TATIČ M. - HF TU Košice, Slovakia 
TJUTČEV I. - Izomat o.o.c., Kiev

Vysoké investičné náklady na stavbu agregátov vyžadovali dlhodobý charakter ich užitia, merateľný desiatkami rokov. Zvyšovanie produktivity a kvality výroby hutníctva je v súčasnosti umožňované vysokou úrovňou technológie a techniky súčasnosti. Je zrejmé, že funkčná životnosť agregátu s technickou úrovňou z doby jeho vzniku je v nesúlade s požiadavkami (ekonómia energie) a možnosťami (nové technické a technologické riešenia) súčasnej doby a nutne vyžadujú radikálne úpravy agregátov. Príspevok na príklade Poklopových pecí užívaných na Ukrajine, Slovensku dokladuje možnosti výrazného zefektívnenia ich činnosti a ekonomizácie prevádzky prostredníctvom variantnosti riešenia výmurovky PP.

FRÖHLICH L., DZUBÁKOVÁ K., FRÖHLICHOVÁ M., ŠPEŤÚCH V. – KK HF TU Košice, Slovakia

Práca sa zaoberá zmenami priebehu sušenia vzoriek žiarobetónového monolitu vplyvom prídavku urýchľovača tuhnutia do vytváracej zmesi. Štúdium sa realizovalo na základe merania úbytkov hmotnosti skúšobných teliesok v dvoch teplotných intervaloch a to, od 23 do 120°C, uvoľňovanie voľnej vody a od 120 do 800°C, uvoľňovanie viazanej vody z hydrátov. Boli namerané kinetické krivky procesu sušenia a niektoré ďalšie kvalitatívne parametre monolitu: pevnosť v tlaku, pórovitosť a objemová hmotnosť.

The paper deals with the changes of drying process caused by the solidification accelerator added into the mixture during the sample drying of refractory concrete monolith. The study was carried out based on the weight reduction measurement of test sample in two temperature intervals that is from 23°C to 120°C (release of free water) and from 120°C to 800°C (release of adhesive water). Kinetic curves of drying process and some other qualitative parameters of monolith were measured: firmness in pressure, porousness and volume weight.

PALMISANO G., GONDOLF M. - Calderys Refractory Solutions GmbH, Austria

Succesful application of ecological of resin-bonded tap hole clay

ŠVÁB J., BUČKOVÁ S., HORVÁTH L., SUCHÝ T. – KPaT HF TU Košice, Slovakia

Matematické modelovanie vplyvu parametrov difúzneho horáka zmenou geometrických parametrov, konštrukčných úprav, prebytku spaľovacieho vzduchu a výkonu horáka pomocou (CFD) modelovacieho softwaru pre optimalizáciu spaľovania v pecných agregátoch.

The Mathematical modeling of the diffusion burner parameters effect on its performance. The regulation of the burner is executed by the geometry and construction changes implementation and also by the regulation of the air excess and natural gas input. The modeling will be realized by (CFD) modeling software for the combustion optimization in furnace aggregates.

CZAPKA Z. - Zakłady Magnezytowe “ROPCZYCE” S.A, Poland

Gas-purging plugs are during operation exposed to the influence of numerous destructive factors. The major ones are: vehement temperature variations during the start of operation and during plug surface cleaning, large temperature gradient in the material during the operation of a plug, erosion caused by steel flow, and corrosion produced by slag and iron oxides during plug cleaning. Durability of gas-purging plugs depends concurrently on the physical and chemical properties of its refractory material, on the constructional solution of the plug, and on the conditions and method of their operation.

KOCHURA V. - Donetsk National Technical University, Ukraine

Replacement of metallurgical coke by pulverized coal (PC) injected in blast furnace (BF) tuyeres is a major economical challenge, due to the high price of coke and unfavorable effect of its production for the environment. The first in Europe commercial complex for PC preparation and injection was built in 1980 at Donetsk Steel Plant (DSP) in Ukraine. The effective use of expensive PCI complexes can be attained when consumption rate of coal gets to maximum. The main factors which hinder the rise of PC quantity being injected into the hearth of furnaces is the maintenance of its complete gasification within the raceway and smooth operation of a furnace due to change of heat, slag-formation and gasodynamical conditions. Burning of carbon in solid fuel is a heterogeneous process. The results of calculation showed that under conditions of BF process of PC burning exists in the diffusion regime. Obtained theoretical results were confirmed by experimental examination on a laboratory rig. A tuyere design for PCI has been developed. Injection of different PC in the raceway can be used. Theoretical and experimental researches of PC burning process under conditions of raceway of blast furnace have been carried out.

POSKART M., RADOMIAK H., SZECÓWKA L. - Czestochowa University of Technology , Poland

Fuel combustion is the most important process in acquiring prime energy. It is also the main source of pollution emitted to the atmosphere. This is important to facilitate and optimize the combustion process according to ecological and power industry criteria. The problems of emission reduction of pollutants, particularly of NOx and CO are definite necessity because of permanent intensification of combustion process and rigorous environmental protection principles. This force to develop new methods of combustion technology and burners construction in order to reduce the emission of nitrogen and carbon oxides. High temperature of a flame is a characteristic feature of natural gas combustion in industrial furnaces. It results in intensification NOx formation. Therefore the basic aim of primary methods of NOx reduction is decreasing of combustion temperature. The presented paper describes the influence of the recuperation and one of the primary methods reduction - air staging on the reduction of NOx and CO concentration. The taken research showed, that concentration of NOx and CO slightly increases simultaneously with the portion of heated combustion air.

BARAŃSKY J., WITEK J. – Instytut Materialów Ogniotrwałych, Gliwice, Poland 

The technology of refractory monolitic blocks with high mechanical properties and superior abrasion resistance was worked out and implemented in Institute of Refractory Materials. Such a products are characterized by excellent corrosion resistance against attack of scale generated during thermal processing of steel ingots and blooms and also high thermal shock resistance. Fundamental properties of this products are quoted below: Al2O3 content min. 55%, ZrO2 content min. 10%, crushing strength after firingat 1350°C min. 120 MPa, abrasion resistance at 1 000oC max. 0.04 g/cm2, thermal shock resistance (850oC/water) min. 20 changes. Worked out monolithic blocks were applied in heating zone of several pusher furnaces used for thermal processing of steel slabs and blooms where 12-18 months service life was confirmed (comparable service life was observed for lining made of fused Al2O3-ZrO2). It was confirmed that monolithic blocks were characterized by excellent application parameters in workong conditions of pusher furnaces at temperature 1 280-1 300 oC.

LANG K., NEVŘIVOVÁ L - P-D Refractories CZ a.s., Velké Opatovice, Czech Republic

Nejrozšířenějším oxidem v přírodě je SiO2 (výskyt v přírodě představuje cca 55%), proto je také jen logické, že je často využíván v technické praxi – v žáromateriálech. Soustava SiO2 je v oblasti žárovzdorné výroby velmi známá a využívána od dob, kdy je známé zpracování kovů. Práce se zabývá popisem jednotlivých druhů surovin a žáromateriálů s vysokým obsahem SiO2, zabývá se jejich popisem a charakteristikami a především použitím v praxi.Úspěšné a efektivní použití žárovzdorných výrobků na bázi SiO2 je především v chování při vysokých teplotách. Přestože má SiO2 z technických oxidů nejnižší bod tání (1726°C) existuje celá řada specifických důvodů proč jsou tyto výrobky trvale používány.

The most widely distributed oxide in the nature is SiO2 (its occurrence in the nature represents circa 55%). Therefore, it is logical that it is very often used in technical practice – in refractories. The SiO2 system is very well known in the field of refractory production and has been used since the metal processing became known. The paper deals with the description of individual kinds of raw materials and refractories with a high content of SiO2, their characteristics and especially with their utilization in practice.Successful and effective usage of refractory products on basis of SiO2 is particularly expedient in their behaviour at high temperatures. Though SiO2 has the lowest melting point out of all the technical oxides (1726°C), there exists a large scale of specific reasons to use these products permanently.

DOBSKI T. - Poznan University of Technology, Poland

It will be presented results of combustion of natural gas in gas burners with regenerative of heat from flue gases into air up to 950 °C of preheating . The emission of nitric oxides as well total heat transfer from flame into material will be men focus of paper. The full planar section of temperatures, molar fractions of chemical species and total heat transfer in semi- industrial experimental combustion chamber will be presented. Also total emission of nitric oxides and unburnt hydrocarbons and CO in exhaust gases in versus of equvalence ratio and effciency of fuel utilisation also will be presented.

IVĂNESCU L., IVĂNESCU A., VASILESCU E., DONIGA A. - „Dunărea de Jos” University of Galaţi, Romania

Presently, at the air preheaters of furnaces, furnace gas in mixture with methane gas is used as fuel. The paper presents a theoretical study and a practical application of heating the air preheaters of furnaces using furnace gas in 100% proportion. The substitution of the bi-gas (furnace gas and methane gas) with 100% furnace gas leads to an important economy of methane gas, which is an expensive, deficitary gas. Considering the actual global energy market, this research study has a major importance.

KAUTZ M., WALTER G. - TU Bergakademie Freiberg, Germany 
GIESEL S. - DBI-Gastechnologisches Institut Freiberg, Germany

Support of this work by the AiF / DVGW – Deutsche Vereinigung des Gas- und Wasserfaches e.V., Köln / Bonn, Germany is gratefully acknowledged. Surface and pore burners play an increasing role in modern thermal processing plants, e.g. during the thermochemical heat treatment of steel, in afterburning plants for residual gases from thermal processes, in natural gas reformers for hydrogen production for fuel cells and combustion engines, in boilers for Stirling or steam engines. These burner types are characterised by an extremely low pollutant emission, since the burnout is very high by the swirled flow and the flame temperature remains low because of the combination of convective and radiant heat transfer. The advantages of the burner technology suggest an increasing employment in the capacity range from 1 to 70 kW. A special problem with the combustion of hydrogen rich gas in surface and pore burners is the reliable monitoring of the flame, with changing gas compositions and high portions of hydrogen. Sensors can be used for flame monitoring detecting the flame via different principles: - thermo electrical: power generation in thermocouple (DIN 125), - optical: measurement of the flame radiation in infrared or in ultraviolet spectrum, - electrical: measurement of the ionisation current due to electrical conductivity of the flame. The flame monitoring of the combustion of hydrogen rich gas is presently realised by measuring the temperature in the combustion chamber. However this kind of flame monitoring is slow and unsuitable for closed combustion chambers. Optical techniques are failing because the flames are very small and not reachable. As a result of the low flame temperature the intensity of flame radiation is not high enough to differentiate certainly from the surrounding radiation. The ionisation monitoring, well known for most other burners, is a relative simple, cost-efficient and well-proven technique using the rectifier effect of the flame for monitoring. The control of the ionisation current in case of burning hydrogen rich gas has problems, which should solved in this project. Aims of the project: • finding the correlation between ionisation current and variable values of the combustion like - gas composition and air/fuel ratio - layout, size and form of electrodes in the burning area as well as - temperature allocation • calculation of working points with CFD (Fluent); calibration of the calculation modell with results from the burner model • design of a concept for non-delay flame monitoring using ionisation current which can be used for - burning natural gas, hydrogen rich gas or changing mixtures of both as well as - large adjustment range

OVČAČÍK F., OGROCKÁ K., HAŠEK P. - VŠB-TU Ostrava, Czech Republic

Tento článek se zabývá tím, který z nových typů žárovzdorných materiálů má největší životnost v odpichovém uzlu tandemové pece. Jedná se o žárovzdorné materiály, které výrobci primárně určují pro použití v takto vysoce exponovaných místech. V článku je popis použitých laboratorních metod a výsledky stanovení odolnosti proti korozi, odolnosti proti otěru, vyhodnocení rentgenové fázové analýzy a také vyhodnocení chemické bodové mikroanalýzy. Ze souboru těchto zmíněných metod vyplývá vlastní doporučení pro aplikaci jednotlivých druhů žárovzdorných materiálů do odpichového uzlu tandemové pece.

This paper deals with the most suitable type of refractory material that has the longest lifetime in the tapping node of the tandem furnace. Such materials are primarily intended for high – exposed places. In the paper is the description of laboratory methods and the results from abrasion and corrosion resistance tests as well as XR-phase analysis and chemical point microanalysis. Out of these mentioned methods result the very recommendation for application of particular refractory types in tapping node of tandem furnace.

STRÁNSKÝ K., KAVIČKA F., DOBROVSKÁ J., HEGER J., SEKANINA B., ŠTĚTINA J. - VUT-FSI, Brno, Czech Republic

Numerický model teplotního pole odlitku z keramiky EUCOR řeší nestacionární třírozměrné teplotní pole soustavy odlitek-forma-okolí po dobu jeho tuhnutí a chladnutí v licím poli. Numerický model chemické heterogenity umožňuje popis a měření dendritické segregace konstitutivních prvků a příměsí v tuhnoucím a chladnoucím odlitku. Oba modely současně využívají teorii podobnosti, operují s přesně definovanými fyzikálně-chemickými veličinami. Spojení obou modelů umožňuje kvalifikovaný odhad koeficientů difúze a tím také intenzity difúze prvků během tuhnutí, tj. za teplot velmi blízkých teplotě solidu. Zhodnocením výsledků měření chemické mikroheterogenity vzorků z odlitku s využitím výpočtu místní doby tuhnutí podle modelu teplotního pole a modifikovaného Brodyho-Flemingsova modelu pro popis odměšování oxidických složek tuhnoucí keramiky bylo ověřeno, že spojení obou modelů umožňuje semikvantitativně posoudit kinetiku tuhnutí této speciální žáruvzdorné a otěruvzdorné keramiky. Jmenovitě je možno stanovit strukturní parametr řídící odměšování, známe-li koeficienty difúze odměšujících složek, popřípadě posoudit koeficienty difúze složek, odhadneme-li velikost strukturního parametru.Výsledky ukazují, že oxidické taveniny se řídí velmi podobnými zákonitostmi krystalizace jako taveniny kovové.

The numerical model of the temperature field of a EUCOR casting considers the 3D transient temperature field of a system comprising the casting-mould-ambient during its solidification and cooling within the pouring field. The numerical model of chemical heterogeneity is capable of describing and measuring the dendritic segregation of the constituent elements and additives inside the solidifying and cooling casting. Both models simultaneously utilize the theory of similarity and exactly-defined physical and chemical quantities. The combining of both models makes it possible to make a qualified estimate of the diffusion coefficients and, therefore, also the element diffusion intensity during solidification, i.e. at temperatures very close to that of the solidus. It also makes it possible to assess (semi-quantitatively) the kinetics of the solidification of this special heat- and we ar-resistant ceramic. An evaluation confirmed the results of the measurement of the microheterogeneity of the samples from the casting, together with the calculation for determining the local solidification time – according to the temperature field model and a modified Brodyho-Flemingsova model for the description of the segregation of the oxide components of the solidifying ceramic. It is possible to determine the structural parameters controlling the segregation, providing the coefficients of the diffusion of segregating components are known, or to assess the coefficients of the diffusion of components, according to the magnitude of the structural parameter. Results indicate the oxide melts are governed by laws of crystallization very similar to those of metal melts.

KOLLEROVÁ I., PALČO Š., KARIČKOVÁ A., - U. S. Steel Košice, s.r.o. , Slovakia

V oceliarskych panvách sa v súčasnosti používajú v podstate dva základné druhy žiarobetónov. Sú to zmesi s prídavkom syntetického spinelu, alebo sú to spinelotvorné betóny, v ktorých sa spinel postupne tvorí in-situ, reakciou medzi MgO a oxidom hlinitým, v prevádzke, po inštalácii betónu do panve. Spor o výhodách, či nevýhodách, použitia toho-ktorého betónu nie je v odbornej literatúre ukončený. Tento príspevok stručne zhodnotí doteraz známe publikované údaje. Každý z týchto dvoch typov žiarobetónov má svoje špecifiká, ktoré je potrebné zohľadniť pri navrhovaní zloženia konkrétnych zmesí pre danú aplikáciu. Z tohoto hľadiska je výber vhodného stekucovadla nanajvyš kritický, pretože ovplyvní nielen reologické vlastnosti zmesí, ale aj technické a technologické parametre betónu dôležité pre trvanlivosť betónu v servisných podmienkach. Voľba vhodného spojiva, ako aj vhodného typu magnézie, je kľúčom k úspechu pri n avrhovaní zloženia spinelotvorného žiarobetónu.

Recently, two types of castables are predominantly used in steel lades. Those are spinel containing castables, and spinel forming castables with in-situ spinel formation at high temperatures in service conditions. Discussion on advantages or disadvantages of the two castables is not finished yet. This paper will briefly summarize the known published data in literature. Each of the two castables has some specifics, which have to be taken into account when designing the composition of castable for particular application. Selection of proper dispersants is very critical for the rheological properties and subsequently for the technical and technological parameters of mixes, and ultimately for the performance of castable in service. The choice of optimal binder, as well as of the suitable type of magnesia, is the key for successful design of spinel forming castable.

MENUGE J. – TRB, Nesles, France

Možnosť využitia kompozitných materiálov v oceliarenstve
ECOFIB is not 100% steel and not 100% refractory material but a composite of both.Only available as precast shape, ECOFIB is a high strength, high thermal shocks resistance product for high temperature applications. ECOFIB is the solution when thermomechanical stress is too high in a range of temperature where conventional refractory materials are mainly brittle. ECOFIB allows to improve the lifetime of conventional castable made precast shape.TRB ECOFIB technology is available for many different applications from cement industry to steel-making plants.Each application is specifically designed by TRB engineering department, followed on-site by TRB technical team, in order to fulfill customers needs.

KUFFA T., SÚČIK G, KUFFA S. – KK HF TU Košice, Slovakia

Práca pojednáva o vývoji smojných spojív pre MgO-C žiaruvzdorné materiály s nízkym obsahom uhlíka. Pre zvýšenie pevnosti a koróznej odolnosti bola použitá tepelne upravovaná čiernouhoľná smola s nízkym obsahom prchavých-ekologicky závadných zložiek. Laboratórne vzorky boli tepelne upravované do 1000°C a pri izbovej teplote sa stanovila pevnosť v priečnom ťahu. Zvolil sa optimálny spôsob úpravy domácich smôl.

Work deal about pitch binders development for MgO-C refractories. To improve strength and erosion resistance a pre-treated coal-tar pitch with the lower volatile-emision content was used. The laboratory samples have been treated up to 1000oC and cross tensile strength have been fixed up at the room temperature. The best way for tratment of domestic pre-treated coal-tar pitch has been selected.

SOCHA L., BAŽAN J. - VŠB-TU, FMMI, Ostrava, Czech Republic

Práce je věnována studiu korozních jevů na fázovém rozhraní žárovzdorný materiál – tekutá ocel. Pro vlastní studium korozních jevů byl vytvořen postup hodnocení, který se skládá z různých metod, mezi které patří např.: vizuální hodnocení, mikroanalýza struktury a RTG fázová analýza. Při hodnocení uvedenými metodami bylo provedeno i stanovení stupně koroze a eroze žárovzdorných materiálů. Uvedeným postupem bylo provedeno hodnocení různých druhů žárovzdorných materiálů na rozhraní s tekutou ocelí. Vyhodnocením jednotlivých metod byly získány údaje o chování žárovzdorných materiálů při kontaktu s tekutou ocelí.

The paper is devoted to the study of corrosion phenomena on interface refractory material – liquid steel. The evaluation procedure was created for proper study of corrosion phenomena. It consists of various methods – for example: visual evaluation, microanalysis of structure and X-rays phase analysis. Even determination of corrosion and erosion degree for refractory materials was done under evaluation by presented methods. The various refractory material types were studied on this liquid steel interface. The characterization of refractory material in contact with liquid steel was obtained by these method’s evaluations.

KOVÁŘ P., LANG K., NEVŘIVOVÁ L. - P-D Refractories CZ a.s., Velké Opatovice, Czech Republic

Tepelně izolační žáromateriály - nedílná součást konstrukcí pecních agregátů – jsou vyráběny rozdílnou technologií. Hodnocení a zatřídění těchto materiálů se provádí jednak podle ČSN EN 1094 – 2, ale častěji je používaná ASTM C 155 – 88. Normy zařazují tepelně-izolační žáromateriály pouze podle objemové hmotnosti a klasifikační teploty určující teplotu použití. Tyto základní charakteristiky zcela nezaručují úspěšnou aplikaci tepelně izolačních žáromateriálu v různých částech vyzdívek pecního agregátu a je zapotřebí znát ještě další vlastnosti žáromateriálu. Způsoby hodnocení použití a zjišťování vlastností jsou popsané na jednotlivých příkladech tepelně izolačních materiálů vyráběných rozdílnou technologií.

Insulating refractories – integral part of the furnace unit structures– are being produced by different technologies. The evaluation and classification of these materials is being carried out in accordance with CSN EN 1094 – 2 or more frequently with ASTM C 155 – 88. The standards classify the thermal and insulating refractories only in compliance with volume mass and ranking temperature which determines temperature of application. These elementary characteristics do not entirely guarantee successful application of thermal insulating refractory in different parts of furnace linings of the unit; it is necessary to be acquainted with other properties of refractory as well. The way of assessing the application and finding out the properties has been described in particular examples of thermal and insulating materials produced by various technologies.

ŠVIDRAŇ I. - Slovmag, a. s., Lubeník, Slovakia

Popis súčasného technického a technologického stavu TP. Bilancia tepelných strát cez strop. - Návrh na zníženie tepelných strát úpravou skladby žiaruvzdornej výmurovky stropu s využitím ŽM z vlastnej produkcie

Description of actual technical and technological state.- Summary of heat-losses across the ceiling.- Suggestion on reduction losses by adjustment of refractory materials of ceiling, by using refractory materials from self-production.

TOMŠŮ F., WALLO K. – Bratislava, Slovakia

Popisujú sa výmurovky moderných kotlov na spaľovanie komunálnych odpadov so zavesenými membránovými stenami chránenými zo strany kotliska tenkostennou výmurovkou. Úlohou výmurovky je chrániť membránové rúrkové steny kotla pred agresívnymi spalinami a zabezpečiť čo najväčší prestup tepla zo spaľovacieho priestoru na membránové steny. Výmurovky sú namáhané tepelne chemicky a mechanicky. Popisuje sa vplyv prevádzkových podmienok na správanie sa výmurovky. Uvedeným podmienkam najlepšie odolávajú žiaruvzdorné materiály na báze karbidu kremíka. V spodnej časti výmurovky sa najčastejšie inštalujú zavesené SiC-dosky s nitridovou väzbou, v hornej časti sa uplatňujú SiC-žiaromonolity s hydraulickou alebo s chemickou väzbou.

Refractory lining systems for the protection of boiler tube walls of waste incinerators are described. The refractory lining protects the tube walls for the aggressive combustion products and provides a high heat transfer to the wallls. The lining is exposed to thermal, chemical and mechanical stresses. The effect of operating conditions on the lining behaviour is described. Best resuls are obtained with silicon carbide nitride bonded plates in the lower part and with silicon carbide hydraulic or chemical bonded monolithics in the upper part of the lining.

OBROUČKA K., VLČEK J., FERKOVIČ J., FIEDOR J., PALUSKA J. VŠB - TU Ostrava, Czech Republic

Vsázka spalovaného odpadu je ve valné většině případů tvořená na základě zkušeností provozovatele zařízení. Tento postup může pak vyžadovat souběžné spalování podpůrného paliva v reakčním prostoru pece a spalování potom nepředstavuje energetické využití odpadů. Intuitivně tvořená vsázka dále nezohledňuje množství znečišťujících složek odpadu, což v případě jeho spalování může představovat značný problém. Dalším průvodním jevem popsaného postupu spalování odpadů je nevyrovnaná produkce odpadního tepla. Záměrem práce je vytvoření matematického modelu tvorby vsázky spalovaného odpadu a jeho následné ověření provozním měřícím experimentem na spalovně nebezpečných průmyslových odpadů. Úkolem modelu je zabránění vzniku výše popsaných problémů.

The incinerated waste charge is in most cases realized by experience of owner’s device. Such technique doesn’t guarantee waste incineration in the regime of it’s energetic utilization whose result is the necessity of additional fuel burning in the furnace. Intuitively designed furnace charge hardly considerates the contaminating components amount in the waste, what is significant problem in case of waste incinerator. Other attendant phenomenon of the described waste incineration process is the variable production of the exhaust heat. The goal of this work is the design of the mathematical model of incinerated waste charge creation and its experimental checking on incineration dangerous industry waste. This model prevents the above mentioned problems to arise.

PARNAHAJ J., MOLNÁR V. – Refrako s. r. o., Košice, Slovakia 
TOMŠŮ F. – Bratislava

Súčasne trendy v navrhovaní a realizácií výmuroviek oceliarenskych panvy v podmienkach DZ OC U.S.Steel Košice s.r.o. využívajú kombinácie betónovania dna špecialnymi žiarobetónmi a murovania valcovej časti stavivami. Pradnáška zahrňuje vývoj samotečúceho , nízkocementového žiaruvzdorného betónu, jeho charakteristiky a aplikácie vo výmurovke dna oceliarenskej panvy v podmienkach DZ OC U.S.Steel Košice s.r.o.

Recent trends in designing and making steel ladle linings at USS Steel Shop use combination of concrete bottom which is casted by special refractory castable and cylindrical brick-layed part. Lecture covers design of self-flowing low-cement refractory castable, its characteristics, and application on bottom linings of steel ladles at U. S. Steel Košice s.r.o.

WYLECIAŁ T. - Polytechnika Czestochova, Poland

It was shown in this work possibility of introduce mechanically crush sorbent in the combustion conduit in dry method of desulfurization. On the testing stand, laboratory tests of combustion-gas sulfur removal were carried out. The testing stand was composed of a gas burner with associated equipment, a burning chamber and a jet mill. SO2 was supplied directly to the burning chamber with a constant stream, while the jest mill (with two countercurrent jets serving for breaking up the sorbent) located behind the chamber drew in loose material of different grain size. The analysis of combustion gas after the cyclone was performed by using a Testo 350 combustion-gas analyzer.

KALOUSEK Z. - Ústav využití plynu Brno, s. r. o., Czech republic

Regenerační systémy jsou energeticky nejúspěšnejší ze všech topních systémú a mají proto zásadní význam pro budoucnost. Jejich konštrukčně nové varianty a možnosti jejich aplikace na rúzné typy pecních agregátú.

The regeneration systems are the most energy- saving of all heating systems and for that reason they have a basic importance for a future. Their new constructionally variations and abilities of their application for different types of kiln units are the theme of the lecture.

DESVIGNES C. - Thermal Ceramics, Saint Marcellin en Forez, France

Thermal Ceramics was the first to provide the market with low bio-persistence fibres under the registered trademark SuperwoolTM 607TM. Over the years, Thermal Ceramics has applied constant effort to developing new compositions with a low bio-persistence to help customers fulfil their RCF substitution obligation. Superwool 607 HT is a new and unique, patented calcium magnesium silicate insulation wool, exonerated from any carcinogenic classification under nota Q of the directive 97/69EC. It offers a higher temperature resistance with low shrinkage up to the maximum use temperature. Insulating wool for furnaces is rated for continuous use at 1150 C, paper and vacuum formed products can work at temperatures as high 1260 C. This level of performance means that many applications, where today RCF is the only feasible solution, will tomorrow have a solution, which meets EU H&S requirements.

POPOVIČ P., BERNÁT P., SIMKO S., KOSŤUOVÁ - Refrako s. r. o., Košice, Slovakia

Vývoj výmurovky KK od stavív magnéziodolomitových po pásmovú výmurovku z MgO - C stavív so sférickým dnom.
BOF lining development from Magnesia-Dolomite bricks to spherical bottom zonal lining made of MgO-C bricks

WYCZÓŁKOWSKI R., MUSIAŁ D., SZECÓWKA L. Czestochowa University of Technology, Poland 

In this paper, calculation of lrad coefficient for simplified model of radiation heat exchange in rods bundle are presented. Moreover calculations of this coefficient for others, similar models which are described in literature are made. On its base discussion about effects are carry out. The calculations targets in a determination influence of temperature, emisivity and diameter of rods on lrad value. The results obtained out of these investigations will be indication for technical staff which service furnaces for heat treatment of steel rods.

PRIESOL I., SLOSIAR Š. - I.P.C. Refractories, spol. s r.o., Košice, Slovakia

Tento príspevok pojednáva o aplikácii nízkocementového na báze andaluzitu na poklop panvovej pece pri sekundárnej výrobe ocele. Sleduje sa vplyv jednotlivých faktorov na životnosť poklopu ohrievacej pece. Cieľom zavádzania žiarobetónu na poklop panvovej pece je zvyšovanie životnosti a znižovanie mernej spotreby žiaruvzdorných materiálov.

STANO F. - MOTIM, representative for Slovak and Czech Republic, Trnava, Slovakia 

Príspevok popisuje nedeštruktívne skúšky korundobaddeleyitových žiaromateriálov (AZS) vykonávané u výrobcov v rámci výrobného procesu.

VIKULIN V. V., RUSIN M. Y., RUSANOVA L. N. - The State Research Center of the Russian Federation - Obninsk Research and Production Enterprise "Technologiya", Russia

A new technology has been developed for making refractory products based on the naturally occurring wollastonite (calcium metasilicate) for aluminum industry. The application of the natural wollastonite requires no hydrothermal treatment in an autoclave, which considerably simplifies the manufacturing process and reduces its cost. A qualitative comparative analysis of the natural wollastonite from different mineral deposits was made to choose an optimal modification with consideration for its availability. The articles were made by using steel-mold pressing, slip casting and vacuum forming methods.For the development of technology for manufacturing large-sized complex-shaped products the slip casting method was used and the slip basic composition was determined comprising 80% of wollastonite as a basic solid phase and 20% of placticizers. The improvement in the thermal resistance of wollastonite-based ceramics is assured by applying special techniques, namely by an addition of course-grained fillers. Thus, the addition of about 15% of a course-grained fraction into the fine wollastonite-based slip improves the thermal resistance of ceramics and affords 2-3 times increase in their service life. The efficient way to increase the wollastonite-based ceramics thermal resistance is an addition of inorganic fibers. With the use of an inorganic fiber, the materials have been produced having a various apparent density ranging from 0.5 to 1.5 g/cm3 and an ultimate compressive strength of 0.5 to 10 MPa. The study has been made into ceramics structure comprising inorganic fibers.The developed materials are chemically inert to the aluminum melt. They show no sticking, no mechanical erosion and they are thermal-resistant.With the above methods, the following products are being made on the basis of the naturally occurring wollastonite: spouts, lining plates, heat nozzles, stopper-rod devices, pipes and other articles that have been operating successfully in aluminum industry of Russia.

KIELOCH M., BORYCA J., PIECHOWICZ Ł. - Technical University of Czestochowa, Poland

It present results of analytical accounts of the losses of steel in the scale. Influence of heating rate up discuss on loss of steel. On base of theoretical derivation, formulate of mathematical model of the two-stage heating process of steel charge. Processed model has enabled accounts of the losses of steel on the scale during two-stage heating process. It carries numeric accounts for verification of process model and laboratory research. It executes analysis of influence of heating technology on loss of steel and temperature of surface heated charge. Influence of thermal and chemical parameters of heating process on the scale adhesion has discussed.

PIECHOWICZ Ł., KIELOCH M., BORYCA J. - Technical University of Czestochowa, Poland

On base of personal results of research and accounts has established co-dependence of consumption of heat and losses of steel in the two-stage heating process. It present results of numerical accounts of consumption of heat and losses of steel on the base of mathematical model of pusher furnaces. Results of numerical accounts and laboratory research have been subjected mathematical analysis. It establish, that it is possible to describe dependence of consumption of heat from loss of steel it is possible to describe analytical equaling.

BEZBORODOV D. L., SAFYANTS S. M., POPOV A. L., SAFONOVA E. K. – Donetsk National Technical University, Ukraine

The problem of oxidation-and-reduction reactions development with minimized fuel-and-energy consumption and mutual relations of technological parameters with respect to combustion active area height during sintering process are discussed in this paper.

GRAMBÁLOVÁ E. - Technická Univerzita Košice, Hutnícka fakulta, Katedra keramiky

Táto práca pojednáva o interakcii chloridu sodného s korundovým žiarobetónom, pričom bolo nevyhnutné nájsť vhodnú metodiku jej makroskopického vyhodnocovania. Experimenty boli realizované statickou teglíkovou koróznou skúškou.
Keďže je chlorid sodný bezfarebný, nie je viditeľný jeho prienik do žiarobetónu po koróznej skúške. Preto bolo nevyhnutné nájsť vhodnú metodiku makroskopického vyhodnocovania týchto skúšok. Po zisteniach, že prídavok farbiaceho chloridu nieje vhodný spôsob, bol nájdený iný, a to pomocou zriedeného roztoku Ag(NO)3. Počas experimentov bola pozornosť venovaná taktiež zrnitosti používaného žiarobetónu, teplote a dobe experimentu.

GUSCHLOVÁ Z., HAMÁČEK J., STRAKA J., KUTZENDÖRFER J. – Department of Glass and Ceramics, Institut of Chemical Technology in Prague, Praha, Česká republika

HAMÁČEK J., GUSCHLOVÁ Z., STRAKA J., KUTZENDÖRFER J. - Department of Glass and Ceramics, Institut of Chemical Technology in Prague, Praha, Česká republika