NO743731L

NO743731L -

Info

Publication number: NO743731L
Application number: NO743731A
Authority: NO
Inventors: U Schuster; E Man; A Serban; V Barna
Original assignee: Portelan Cluj Intreprinderea D
Priority date: 1974-10-16
Filing date: 1974-10-16
Publication date: 1976-04-21

Abstract

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Description

Ildfast blanding for brennhjelpemidler,^anvendtRefractory mixture for burning aids,^used

ved brenning av keramiske produkter.when firing ceramic products.

Foreliggende oppfinnelse angår ildfas.te blandinger for brerin-h.jg lpem idler anvendt ved brenning av keramiske gjenstander, slik som f.eks. steintøy, steingods, porselen og produkter i oksydkeramikken, i ovner med kontinuerlig brann. The present invention relates to refractory mixtures for brerin-h.jg lpem idlers used in the firing of ceramic objects, such as e.g. stoneware, stoneware, porcelain and products in oxide ceramics, in kilns with continuous fire.

Det er kjent forskjellige ildfaste blandinger som anvendes til fremstilling av keramiske b rennhj elpémid ler, for ved hjelp av disse å kunne brenne finkeramiske produkter og videre deres sammensetning på grunnlag av silimanit, mullit, kordierit,siliciumkarbid<->^ aluminiumtrioksyd og et keramisk eller organisk bindemiddel. Different refractory mixtures are known which are used for the production of ceramic burning aids, in order to be able to fire fine ceramic products with the help of these and further their composition on the basis of sillimanite, mullite, cordierite, silicon carbide<->^ aluminum trioxide and a ceramic or organic binder.

Disse kjente produkter har generelt et redusert nytteomløps-tall, f.eks. er de som inneholder mullit ellerkordierit ikke motstandsdyktige ved høye temperaturer, videre er de som inneholder silimanit lite motstandsdyktige mot store belastninger og videre kan de som er fremstilt av siliciumkarbid ikke anvendes ved stadige temperaturer på 900-1000°C i oksyderende atmosfærer samtidig som de ikke tåler større termiske sjokk. These known products generally have a reduced useful life figure, e.g. those containing mullite or cordierite are not resistant at high temperatures, further those containing sillimanite are not resistant to heavy loads and furthermore those made from silicon carbide cannot be used at constant temperatures of 900-1000°C in oxidizing atmospheres while they are not withstand greater thermal shocks.

Brennhjelpemidlene ifølge foreliggende oppfinnelse overvinner disse mangler ved at dé består av: 15-i|0 vekt-% og fortrinnsvis 35_^0 vekt-% glødet aluminiumtrioksyd med minst 99 A12°3°s en kornstØrr_ else på ca. 50$ under 0,06 mm og ca. 5Q% mellom 0,1 og 1 mm, 35-MO vekt-% kaolin, samt 20-25 vekt-# og fortrinnsvis 20-30 vekt-% svart siliciumkarbid, krystallisert i heksagonalt system med maksimalt 2% urenheter og en korning på mellom 0,5 og 4 mm. The combustion aids according to the present invention overcome these shortcomings in that they consist of: 15-1|0 weight-% and preferably 35_^0 weight-% annealed aluminum trioxide with at least 99 A12°3°s a grain size of approx. 50$ under 0.06 mm and approx. 5Q% between 0.1 and 1 mm, 35-MO weight-% kaolin, as well as 20-25 weight-# and preferably 20-30 weight-% black silicon carbide, crystallized in a hexagonal system with a maximum of 2% impurities and a grain size of between 0.5 and 4 mm.

Oppfinnelsen skal belyses ved de. følgende utførelseseksempler. The invention must be explained by de. the following execution examples.

I tabell 1 er det angitt blahdingssammensetninger for de ildfaste blandinger, mens egenskapene for de tilsvarende produkter oppnådd ved forskjellige brenningstemperaturer er angitt i tabell 2. Table 1 shows the composition of the refractory mixtures, while the properties of the corresponding products obtained at different firing temperatures are shown in table 2.

Claims

According to the invention, in order to produce combustion aids from the mixtures, which have the greatest possible useful cycle number, a mixture consisting of 35~40% by weight aluminum trioxide, 35-40% by weight kaolin and 20-30% by weight silicon carbide with a grain seed composition is used on:

The kaolin used for this has the following average composition: .52.2% Si <0>2 , .31.85% A12 03 , .1.3% Fe2 03 , 0.5% Ti02 , 0.5% CaO, 0.35% MgO, 0.19% Na2 0,. 0.9% K20, .12.3% glow loss. The combustion temperature for the products produced according to the invention from the mixture as combustion aids is between 1430 and 1530°C, preferably between 1480 and 1500°C. The porosity of the fired refractory material lies between • 22.2 and 35%.> preferably between 25 and 30%, with an apparent specific weight of (l.9j^2. kg/dm3. \ j L1 """" ^ icij ^ j . U ^ dM ^ H. The compressive strength of the fired molded products has been found to be ■between 950 kg 1050 kg/cm <2> . The ceramic burning aids which, according to the invention, are produced from the mixture have the following advantages: they have a useful turnover number of at least 200 at temperatures between 1380 and 1410°C; they withstand relatively large loads without deformation or cracking; they can be used for a longer time at constant temperatures of 900-1000°C i oxidizing medium; they withstand thermal shocks. mÅA Refractory mixtures for the production of firing aids, used when firing fine ceramic products in a kiln with continuous firing, - characterized in that, in order to withstand high temperatures and pressure, it comprises 15-40% by weight, preferably 35-40% by weight, of annealed aluminum trioxide with a minimum of 99.4% A^O-^ and a grain size of approx. 50$ under 0.06 mm and approx. 50% between 0.1 and -1 mm, 35-40% by weight kaolin, as well as '20-50% by weight, preferably 20-30% by weight, black silicon carbide, crystallized in a hexagonal system with a maximum of 2% impurities and a grain between 0.5 and 4 mm.