Fluoride of antimony v. tartar emetic

The Textile Mercury, 13.12.1890

The Committee of Chemistry of the Société Industrielle, of Rouen, requested MM. Ed. Koepp and S. Brieere to report upon the merits of Koepp's substitute for tartar emetic. In a report presented to the Committee, they say:—

"We thought it would be interesting to complete our work by the study of two other similar products which have lately been introduced, viz., the liquid fluoride of antimony and antimony salt, the combination of antimony fluoride and ammonium sulphate. Of the three products Koepp's double fluoride of antimony and sodium is the most interesting. It contains theoretically the greatest amount of oxide of antimony, 66 per cent., and on analysis the samples forwarded to the Society gave theoretical numbers. Antimony salt contains only 47 per cent. Sb₂O₃ and the liquid fluoride of 1,655 sp. gr. only 369 per cent., tartar emetic contains 43,6 per cent.Sb₂O₃.

"Having made a series of experiments with each product in the laboratory, we repeated them in the works, so far as antimony salt and Koepp's fluoride were concerned. We considered that the liquid fluoride was too dangerous tube placed in the hands of the workmen, as if it comes in contact with the skin, very serious burnings are the result. The trials were made in baths containing equivalent quantities of Sb₂O₃ of each substance. These baths were made up as follows:—

"For Koepp's salt:
7.05 kilos. of the fluoride,
6.00 „ soda carbonate,
2,200 litres of water.

"For antimony (De Haen's) salt:
1012 kilos. of the salt,
6.00 „ soda carbonate,
2,200 „ water.

"For comparison of results an ordinary tartar emetic bath was made up as follows:
11 kilos. tartar emetic,
6 „ Soda carbonate,
1,200 litres water.

"On comparing samples of pieces treated in these various baths we found the following results: — Methylene blue was sensibly greener and less full when treated in the first two baths than when fixed by means of tartar emetic. Reds, yellows, greens, greys, etc., were certainly duller. After seeking for the cause of this, see believe it is to be found in the strong acidity of the solutions of the Koepp's fluoride and Lie Haen's salt, whatever the prospectuses of the makers may say to the contrary. In consequence we conclude that neither double fluoride of antimony and sodium (Koepp's salt), or antimony salt can advantageously replace tartar emetic as a fixing agent for the coal-tar colours."