DE598551C - Method of processing refractory clays on cement - Google Patents

Description

Process for processing refractory clays on cement For the production of Portland cement, preference is given to raw materials in which the hydraulic factors of Portland cement, silicic acid; Alumina and iron oxide are present as possible from the outset in sufficient quantities and in inn igster distribution as the z. B. is the case with most marl materials.

Where natural marls are not available, an artificial raw mixture must be produced using clay; only the easily meltable clays are suitable for this purpose, since only with them the smooth union with the lime occurs through the sintering in the cement fire. Clays with a very high softening temperature, clays also, which, in addition to a lot of alumina, contain very little iron oxide and thus form the starting material for the manufacture of refractory products, can, however, be made useful for the manufacture of Portland cement by adding to their lack of iron oxide Equalizes iron oxide or iron oxide-containing materials for the raw mixture, so that the alumina modulus (A1203: Fe203) of the raw mixture goes down to at least 2.5 - but better still further down to about 1.3 .

However, it has been observed that with raw mixtures of limestone and refractory clays made in this way by appropriately adjusting their content corrected for iron oxide, new defects appeared. It turned out that the softening point and the melting point of these raw mixes are very close to one another, so that there is hardly any actual sintering interval left. This will the technical firing is very difficult because of relatively small temperature fluctuations Either light fire or full melting occurs in the furnace. But also the clinker, obtained from raw mixes of the kind indicated, then proved itself as incomplete if the sintering process was carried out smoothly; he delivered cements - which showed irregularities in their dependency and which left something to be desired in terms of their strength properties.

The inventor has now recognized that all of these deficiencies are compounded too deep sinking of the silicate module [Si 0.: (A12 03 + Fe. 03)] can be attributed, a sinking as it must occur; if in one already low in silica Raw mixture of the silica content by the introduction of iron oxide further in favor the sesquioxyde is pressed. Indeed, both the sintering difficulties could as well as the technical deficiencies of the burnt cements are corrected if in the Raw mixture of limestone and refractory clay, corrected with iron oxide, silica or pebbly aggregates introduced in such quantities. were that thereby the silicate module was kept at a reasonable level.

Accordingly, the subject of the present invention is a method for processing refractory clays on cement with the addition of iron oxide or iron oxide-containing masses, as a flux, in which provision is made by introducing silica or silica-containing additives into the raw mixture that the silicate module in the burnt clinker does not occur below the value 1.0 - or, better still, not below the value 1.3 - sinks.

With the difference in the composition of refractory clays with With a high content of aluminum oxide, fixed rules can be set for the quantitative measurement of the surcharges do not set up. The necessary clues for practical implementation of the present invention result from the communicated regulations for the values of the silicate modulus and the alumina modulus obtained when the raw mixture is prepared must at least be achieved. Only as an example may it apply that at Processing of a fireproof clay that is almost free of iron oxide, var and der to 50 parts of silica contained about 30 parts of alumina, about 212 to 40.10 iron oxide and about 3 to 5% quartz sand had to be introduced into the raw mix in order to achieve a to bring about smooth sintering and a cement of excellent properties deliver.

Of course, the lime content of such a corrected raw mixture must according to the well-known rules of cement production, the total content of hydraulic factors be adjusted.

Since the iron oxide is in can replace wide limits by manganese oxide, so can also with the present Procedure the introduction of iron oxide or iron oxide-containing additives by the The introduction of manganese oxide or additives containing manganese oxide are to be replaced.

Claims (2)

PATENT CLAIMS: 1. Method of processing refractory (i.e. high-alumina and low-iron oxide clays on cement, characterized in that in a through the addition of iron oxide (Maugan oxide) or of iron oxide (manganese oxide) Materials prepared raw mixture of limestone and refractory clay of entry premature melting or excessive softening of the mass due to the introduction prevented by silica or siliceous material and thus the sintering interval is widened so far that a smooth process of the sintering and thus the production a cement with good technical properties is assured. 2. Procedure according to Claim 1, characterized in that in a raw mixture of limestone and refractory Clay in which the clay module (A12 03: Fee 03) is added by adding iron oxide (manganese oxide) down to 2.5 - better still down to 1.3 - is reduced, the strong associated with it Decrease in the silicate module- [Si 02: (A12 03 Fe203)] due to the introduction of silica or silicic acid-containing material is balanced again and thus has the effect that the silicate modulus does not fall below r, o - better not below 1.3.