Th. Goldschmidt Ag

Dirk Naumann

Joachim Giersberg

Hartmut Gomm

Frank Honselmann

Glass vessels are coated by spraying a solution containing 86 to 1,290 g/L of (HO).sub.x Sn(C.sub.2 O.sub.4).sub.y on the 500.degree. to 600.degree. C. hot outer surface of the vessels. The solution may contain oxalic acid, HCl and a portion of the (HO).sub.x Sn(C.sub.2 O.sub.4).sub.y compound may be substituted by a compound (OH).sub.2 SnCl.sub.2. The coatings are uniform.

Preparation and method for coating glass vessels

Glass vessels are coated by spraying a solution containing 100 to 1,000 g/L of (OH).sub.2 SnCl.sub.2 on the 500.degree. to 600.degree. C. hot outer surface of the glass vessels. The solution may contain oxalic acid and a portion of the (OH).sub.2 SnCl.sub.2 compound may be substituted by a compound (HO).sub.x Sn(C.sub.2 O.sub.4).sub.y, wherein y is 0.2 to 3.8, y is 1.9 to 0.1 and (2y+x)=4. The coatings are uniform.

A method is disclosed for the preparation of finely divided, electrically conductive tin(IV) oxide. In a first step tin(IV) oxalate and/or oxalates of polymeric tin(IV) compounds are obtained by electrolysis, in which the anode consists of tin or a tin alloy which contains a doping metal, and the cathode consists of a metal or graphite. The two electrodes are separated by a diaphragm or an organic membrane which is permeable to hydrogen ions and oxalic acid solution is used as electrolyte. Tin(IV) oxide is prepared in the second step by calcining the oxalates obtained from the solution of tin(IV) oxalate and/or oxalates of polymeric tin(IV) compounds, to which known doping agents have been added in conventional amounts.

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Essen-Kupferdreh, Germany

Dirk Naumann