DE713176C - Process for the production of a highly refractory building material from the slag produced in the electrometallurgical melting process - Google Patents

Description

Process for the production of a highly refractory building material. the slag arising from electrometallurgical smelting processes. has been proposed to be used in electrometallurgical melting processes., in particular the ferrochrome extraction, resulting slag as a component of the mixture for the production to use refractory bricks, ramming compounds and mortar. According to another suggestion by adding a small amount of artificial slag containing spinel to chrome ore a An increase in the compressive strength of chromite stones produced in this way can be achieved. Refractory bricks, ramming masses and mortar were thought to be. such slags. because of their changing fire resistance due to the strongly fluctuating silica content * and not suitable because of their glassy nature.

The following has been established through experiments: The during manufacture of ferromanganese in the electric furnace show, they tarnish solidified melt flows are not a homogeneous structure, but their constituents are partly in metallic form, partly as oxides of different oxidation levels before. This is apparently due to the extremely short melting time and the setting time due to the slag, which is insufficient for the formation of highly refractory oxide groups. The generally glassy structure of the slags is apparently due to that the slag the temperature peak of about 2ooo ° C, at their formation which in and of itself all the slag components - would have melted so quickly go through that when cooling instead of a complete crystallization of the Metal oxides solidify as so-called supercooled melts to form glasses, turning such slag is crushed and like other sandy masses by high pressure deformed, so find at firing temperatures between iSoo and i8oo ° C Conversions instead, which lead to the destruction of the stone. The stones tear as a result of strong growth and become crumbly. The aforementioned defects also occur a.i # f ;. when the cinder pieces heated to the above 'üÜ ..- given temperature and then zey @ `smaller, deformed and be burned. Such masses show despite repeated fire and the at refractory bricks usually cool, still partially glassy structure.

According to the invention, it was recognized that by re-firing low-silica ferrous manganese slags, these errors are eliminated if the finely ground, generally vitreous slag is added in a finely divided form to a portion of a vaccine that promotes crystal formation, for example ground silica, and a gceignet @ es sinher agent and the resulting mixing ring is pressed and fired at temperatures above SK 2o (about 153o ° C). The process of inoculation should therefore be used to transform the vitreous slag constituents into crystalline ones. Appropriate vaccines are orar flour or serpentine flour. The choice and amount of the vaccine to be added depend on the requirements placed on the end product. Low-silica slags should be understood to mean those with a maximum of lo% silica. Red mud, for example, can be added as a sintering agent. As. If necessary, the addition of sulphite liquor is advisable as a binder. Example slag containing manganese. the composition: Al, O, I Mn O j Si O, Fe, 03, Ca O ' mg 0 remainder 53 16 @ 3 2.5 3.5 18.5 3-5 is brought to a grain size of 0 to 4 mm in a mixer with i Oje red mud, - ° / ° quartz flour and i ° / ° silicanite: mixed. The mass prepared in this way is pressed at 400 kg / cm.degree. To form blanks, these are dried and fired for 24 hours at SK 26 (158o.degree. C.).

The method according to the invention is next to. reshaping the vitreous slag components into crystalline that which is still present in the slag Metal converted into the oxide form. Oxidation of the metal causes a Volume enlargement, which can no longer occur in the finished stone. According to the invention The building materials produced show no significant change in volume when they are used in the oven. In addition to the reasons given above, this seems to be due to the fact that the clay the slag is converted into the permanent f-shape by the repeated firing. The low-silica ferrous manganese slag obtained by the process according to the invention The building materials produced are ideally suited as main or additive for the production of highly refractory bricks. They can also be used alone or as a mixture can be used for highly refractory mortars and ramming compounds.

Claims (1)

PATENT CLAIM: Process for the production of a highly refractory Building material from the slag produced in electrometallurgical melting processes, characterized in that # kieselsäurearrtie F erromanganschlacke_ crushed, with a small proportion of one that promotes crystal formation in the event of a subsequent fire Vaccine. for example finely ground silica, as well as a suitable one Sintering agent mixed in finest distribution, pressed and at temperatures above S.K. 2o (about 1530 ° C) is burned.