IL25503A - Process of manufacturing unfired refractory bricks and compositions of magnesia-chrome and chrome-magnesia - Google Patents

Description

C O H E N Z E D E K S P I S B A C H PATENT ATTORNEYS LEVONTIN 1169 T E L A V V P A T E N T S D E S I G N S O R D I N A N C E SPECIFICATION PROCESS OF MA UFA G UK A COMPOSITIONS OF an Austrian of Austria DO HEREBY DECLARE the nature of this invention and in what manner the same is to be performed to be particularly described and ascertained in and by the following fills invention relates to a process of Manufacturing refractory and compositions of and la a main object of the invention to provide unfi ed bricks of this kind which are at least lent to bricks that have been fired at high above It is another object of the invention to produce unfired chrone and bricks which in their refractoriness under cold crushing bending abrasion resistance to slag attack and other properties are eminently suitable for lining industrial particularly for lining the walls roofs of it is an of the invention to produce refractory compositions or masses which are based on ed chrome and and high refractoriness under cold crushing abrasion resistance and resistance to slag attack and which may be in furnaces metallurgical vessels an as patching and spraying or in shaped condition as tamping It already known that magnesia bricks having valuable properties can be obtained if the bricks are fired at s temperature above before they are Such firing process involves plants in which bricks ere fired at tional the incorporation of firing into the manufacturing programme involves large vestments because firing requires special precautions la order to prevent squeezing of the and to ensure that they at least approximately their dimensions and have dealt with problem by an earlier Patent printed have found how the iring of the bricks at can be According to this prior fired or of and are produced by nixing substances contain ch miam particularly with or sintered if or other natural or synthetic magnesium compounds which yield on firing preferably shaping the mixture briquettes or jointly sintering said substances at temperatures of at least without fusion graining the sintered adding sintered if shaping the grained material nto In this the following measures are employed in in the manufacture of the sintered at least 65 and preferably at least 80 of the substances which contain chromium have a particle above the or the substances which yield magnesia on firing have a particle below preferably most and the sintered material has a silica content of at most preferably at most and a ratio of at most preferably at most resulting sintered material has the properties of material which has been fired high e bond between the subs ances which contain chromium or the ehromlte and This direet bond is also retained during the further processing of the sintered teriel and in the bricks made Without a rature firing of the bricks with Attendeat this process results in bricks which are equivalent to bricks have been at high It s been found in course of further research work that refractory bricks and compositions or masses of and be obtained even then when all process steps according to the prior proposal are but only those measures are adopted which reside that the substances which chromium particularly and the magnesia material are jointly in a shaped condition to firing operation and the in producing the sintered is to silica rstio of at most and a silica content of at most the sintering firing operation taking place at tures of at least the invention relates to a process of producing unfired refractory bricks and compositions or of in which stances that contain chromium particularly are mixed with or sintered if or natural or synthetic compounds which yield on in such proportions that the mixture used in producing the sintered material is to a ratio of at most preferably snd a silica content of at most preferably at most whereafter t e nixt re particularly briquettes or and without fusion at temperatures of at least this sintered material grained if nixed with sintered then shaped are to be such a ratio and the amounts of the latter is present in the of and is not present in disturbing silica content of the sintered material should preferably be less than and it will be even better if this content is than the limitβ as to the ratio end the silica content are a covering of the components which contain chromium particularly of the chromite with silicates will be reliably prevented so that the formation of direct bond between the components which chromium oxide and the formed during firing is at the firing temperatures of at leas formation of this direct bond and a major part of the desirable properties of the unfired bricks compositions or masses produced from this sintered material depend less on the sices of the materials to be sintered than on the silica ratio the silica the production of the sintered material it will be the or the magnesium compounds are used in particle sines of 0 when the to be sintered la shaped into in particle of 0 5 preferably 0 the to he sintered is the component particles than The fores consists ferably of raw or floated raw which gives the best Other or synthetic which fora upon firing be used of raw but the of raw is ces which contain such sintered Also be subjected to the this practice is two firing operations It will be particularly suitable to produce relatively shaped bodies froa the to be sintered if the magnesia nent in relrtively large particle as aay be the particularly with sintered or with s which been by process other the starting are available in particle they aay be shaped also The use larger such as briquettes or results in better such as porosity and raw of the products from the sintered In the production of the sintered at least at least of the substances which contain chroaiua or of the chroalte should have particle The cptiaua else of these substances is 0 6 preferably The sintered should contain preferably 10 30 Another feature of the Invention resides that the grained sintered used in the production of the bricks and masses or compositions with an admixture of at most 55 sintered based on the refractory the amount of sintered he added in form a particle of at most to the grained sintered must exceed 8 and is preferably based on the refractory This means the material may he added to the sintered material includes at most 8 sintered magnesia a particle sise up to and up to 27 sintered a particle else above particle sise of the sintered magnesia should exceed It has also been found that when bricks are produced from the sintered and grained material and this sintered material contains or it is absolutely essential to add magnesia having particle else of at most in an amount of up to 8 preferably 5 based on the refractory because the bricks supplied would not have a sufficiently high cold crushing addition to the refractory the unfixed products according to the invention contain erally an Admixture of a such sulfite cellulose waste liquor or magnesium In the finished product the sintered materiel the ratio should desirably not exceed the content ehould desirably e less The be explained more in detail ference to the following A mixture of 4 wee compacted into briquettes or bricks together 67 floated with an addition of about 10 flue duet saturated wan fired at about sintered materiel comminuted and 67 of this material a particle else of to end 28 a of 0 to were processed into bricks an addition of sintered that had been and referred refractory groun to e powder a particle else below sulfite cellulose liquor saturated serite She bricks were dried a temperature of the following compositions Ignition In a comparison with unfired bricks had virtually the composition in the usual manner from a mixture of chromite snd sintered when fired ilk a tunnel kiln at about the bricks according to the invention exhibited better values se to cold torsional strength The results of the comparison teste be stated in the column refer to the bricks to the and those in the coluMn to the usual Apparent specific grams per cubic centimetre firing in tunnel Cold crushing grass per square centimetre 600 600 Cold crushing after firing tunnel grams per centimetre 290 shock number of quenching store then wore than Refractoriness under above 1700 above 1700 after in tunnel of 40 below speed in degrees per at Bursting The following mixture was used in producing the sintered 72 raw e 12 to 16 dust 2 saturated solution per kilograms of the This into which were fired at resulting sintered be be into the particle sisee in 1 conventional The bricks for use after been dried tered be in asking other refractory or been it particularly in the production of to up to sintered in the form of a fine of 0 if the sintered contains than because the cold crushing strength of the bricks supplied would not be satisfactory sintered not be in excess of 8 because this on the other hand adversely affect the other propertiee of the sintered due to the firing parts by weight 92 of the sintered of 2 paris by weight a particle else of 0 nixed powdered parts by weight 5 f the resulting be in a state be used s on on the type of la or the the oX water or directly the spray noszle la insufficientOCRQuality

Claims (1)

WHAT IS CLAIMED A process of producing unfired compositions and refractory bricks of and magnesia wherein substances containing chromium oxide are mixed with substances which yield magnesia on firing in such proportions that the mixture is ratio of at most and is silica adjusted to a of at most whereafter the mixture is shaped and then sintered without fusion at temperatures of at least and the sintered material obtained is grained if is shaped into if bricks are to be A process as claimed in Claim for the duction of wherein the grained composition is mixed first with magaesia and then shaped into A process according to Claim wherein the stances containing chromium oxide are A process according to

1. Claim 1 to wherein the substances wfiich yield magnesia on firing are sintered or other natural or synthetic A process according to any of Claims wherein the mixture to be sintered is adjusted to a silica A process according to any of Claims the mixture to be sintered is adjusted to a silica content of at most A process according to any of Claims wherein the mixture to be sintered is shaped into briquettes or 7 process according to wherein the the magnesium compounds are used in particle the production of the sintered material when the Mixture to be sintered shaped into 7 9 process according to wherein the ma nesite or the compounds are in particle of 0 preferably 0 3 in the production of the sintered material when the mixture to be sintered is shaped 9 A process according to of claims 1 to wherein at least at least 80 of the substances which contain chromium oxide and are used the production of the sintered material a particle above 10 process according to any of claims 1 wherein the sintered and grained material is the production of the ed and compositions with an addition of at most 35 sintered baaed on the refractory 11 process according to any of claims 1 to wherein sintered magnesia having particle of et most is added to the sintered and grained material la an amount of at most 8 12 A process according to claim wherein the grained sintered magnesia added in an amount of 3 5 12 13 Aprocess recording to claim or wherein grained sintered magnesia a particle of at most added to the sintered grained material in an amount of at most preferably in an amount of 3 5 on the refractory if the sintered and grained Material contains or more A process for the of refractory and of substantially bricks compositions when prepared the process claiaed in any of the THIS 24th day of Attorneys for Applicants insufficientOCRQuality