The present invention relates to essentially chromate free cements and to a process for preparing them. The removal of soluble chromates is carried out during cement preparation by means of the action of reductant aldehyde derivatives.

The present invention provides improved techniques for metallizing ceramic substrates. The method comprises providing a ceramic substrate (20) and depositing a layer of reducible material (30) on the ceramic substrate. The layer of reducible material includes a reducible ceramic such as copper oxide. The ceramic substrate having the layer of reducible material disposed thereon is heated and the reducible material is contacted with a reducing agent to create a conductive region. The conductive region is either a metallized region formed by reduction, or it is a conductive ceramic formed through surface reduction. The present invention further provides a metallized ceramic substrate. The metallized layer comprises ceramic regions (40) having at least one constituent in common with the ceramic substrate. The ceramic substrate and the ceramic regions of the metallized layer are sintered to each other such that the metallized region (42) is interspersed between the sintered ceramic regions. In this fashion, the metal is firmly held to the ceramic substrate due to the presence of the bonded ceramic within the metallized layer.

The present invention provides improved techniques for metallizing ceramic substrates. The method comprises providing a ceramic substrate (20) and depositing a layer of reducible material (30) on the ceramic substrate. The layer of reducible material includes a reducible ceramic such as copper oxide. The ceramic substrate having the layer of reducible material disposed thereon is heated and the reducible material is contacted with a reducing agent to create a conductive region. The conductive region is either a metallized region formed by reduction, or it is a conductive ceramic formed through surface reduction. The present invention further provides a metallized ceramic substrate. The metallized layer comprises ceramic regions (40) having at least one constituent in common with the ceramic substrate. The ceramic substrate and the ceramic regions of the metallized layer are sintered to each other such that the metallized region (42) is interspersed between the sintered ceramic regions. In this fashion, the metal is firmly held to the ceramic substrate due to the presence of the bonded ceramic within the metallized layer.

The present invention relates to essentially chromate free cements and to a process for preparing them. The removal of soluble chromates is carried out during cement preparation by means of the action of reductant aldehyde derivatives.

Hydraulisch abbindender Klebemörtel bestehend aus

A) 10 bis 70 Gew.-% eines hydraulischen Bindemittels,

B) 1 bis 70 Gew.-% Zusatzstoffen auf Basis von puzzolanischen und/oder latent hydraulischen Zusätzen,

C) 10 bis 80 Gew.-% Füllstoffen,

D) 0,01 bis 5 Gew.-% eines polymeren Fließmittels auf Basis von ungesättigten Mono- und/oder Dicarbonsäuren oder Derivaten hiervon und Oxyalkylenglykol-Alkenylethern und/oder -estern,

E) 0,01 bis 15 Gew.-% eines redispergierbaren Polymerisatpulvers und/oder einer Kunststoffdispersion auf Basis von Vinyl- oder Acrylat-Polymeren,

F) 0,01 bis 10 Gew.-% eines Wasserretentionsmittels,

G) 0,01 bis 5 Gew.-% von sonstigen Additiven ausgewählt aus der Gruppe Beschleuniger, Verzögerer, Verdicker, Dispergiermittel, Farbpigmente, Reduktionsmittel, Luftporenbildner und Verarbeitungshilfsmittel sowie

H) als Rest Wasser.

Der erfindungsgemäße Klebemörtel weist hierbei hervorragende Verarbeitungseigenschaften, wie zum Beispiel Aufziehverhalten, Korrigierbarkeit, klebeoffene Zeit, sowie sehr gute physikalische Eigenschaften, insbesondere Bruchbild und Haftzugfestigkeiten, auf. Außerdem werden bei diesem Klebemörtel keine Ausblühungen beobachtet.

Die Erfindung betrifft ein hydraulisches Bindemittel mit dem Hauptbestandteil Zement, dem eine Mischung aus feuchtem Grünsalz und inertem Trägermaterial zugefügt wird. Die Mischung weist erfindungsgemäß eine Körnung mit einem Siebrückstand auf einem 0,2 mm Sieb auf, der kleiner oder gleich 30 % ist. Die Mischung kann zudem zumindest einen der Zuschlagstoffe Zink, Aluminium, Phosphor oder Titanoxid enthalten und wird in einer Menge zwischen 0,01 Gew.-% bis 5 Gew.-% bezogen auf die Zementmenge zugefügt. Der Anteil an inertem Trägermaterial in der Mischung liegt zwischen 5 Gew.-% und 15 Gew.-% bezogen auf die Grünsalzmenge. Als Trägermaterial kommt vorzugsweise ein Silicagel zum Einsatz.

Present invention relates to the method of producing a cement with reduced content of chromium, where 0.01 to 10% by weight of mechanically and/or thermally treated iron carbonates are used as iron correction component for the raw meal, with its subsequent burning at the temperature from 1400 °C to 1500 °C, thus achieving primary reduction of Cr^VI in cement between 0.5 and 20 ppm of Cr^VI. Such prepared cement receives during and/or after grinding chemically treated - activated iron carbonates in amount of 0.01 to 1% by weight, thus achieving final reduction of Cr^VI in cement less than 0,5 ppm.

Disclosed herein is a waste-treating material which comprises cement and at least one reducing metal, effective for stabilizing industrial wastes containing harmful metals like a heavy metal and the like and cyanides. A preferred example of the reducing metal is iron. Additionally the waste-treating material may also contain at least one member selected from a group consisting of a reducing agent, aluminum sulfate, allophane, and bentonite as the auxiliary. The use of this waste-treating material makes it possible to stabilize the hazardous heavy material and the cyanides contained in the industrial wastes, thereby remarkably contributing to a stabilizing treatment of the industrial wastes.