2565. To Remove Aniline Colors

2565. To Remove Aniline Colors. There are various ways proposed to remove aniline colors, the following being the simplest and most practical. Goods dyed with aniline colors may easily be rendered white by the use of zinc gray; the metallic zinc contained in this powder reduces the colors, forming soluble colorless products. To apply the principle, triturate 100 grains zinc gray with 50 grains mucilage marking 20° Baum6, until the mixture is homogeneous; incorporate with this 20 grains of a solution of hyposulphite of soda marking 20° Baum'e, apply this mixture directly to the goods, let it dry and vaporize. After this operation it is best to wash the goods with water slightly acidulated with hydrochloric acid. Cotton goods may be bleached by chlorine or bleaching liquor, but this is not applicable to other than cotton fabrics. Another simple method consists in digestANILINE COLORS ing the fabrics for a sufficient length of time in 90 per cent, alcohol, which usually completes the decolorization in a short space of time. The same alcohol can be used several times in succession, and can afterward be purified by rectification or redistillation, so as to involve but little loss. The work is best done in a well-covered copper kettle, which is to be set in boiling water. A little hydrochloric acid may be added if the articles are not too delicate, thereby increasing the solubility of the aniline colors.

If all other methods fail, cyanide of potassium is absolutely certain. A stone vessel is to be selected, in which a small quantity of cyanide of potassium is to be introduced, and hot water poured upon it, so as to make a solution of 1/2° to 1° Baum'e. The whole is to be stirred well with a long and strong glass rod, and the operation conducted in the open air, so that no harm may result from the condensation of the vapor. The fabric in question, previously well cleaned, is now placed in the vessel, and pushed under the liquid with the glass rod, and the top of the vessel laid on. It is advisable to keep the solution warm, by immersing the stone vessel in a wooden tub properly supplied with steam or hot water. After a short time the lid should be removed by taking it off at the end of a long handle, allowing the vapors to pass off before the operator comes near. By means of the glass rod the cloth is to be lifted, and if not entirely white, is to be replaced and the process continued still longer. "When finished the cloth is to be transferred by means of the glass rod to a large vessel containing hot water, and stirred around for a time, then removed and rinsed off. The solution of the cyanide of potassium can be used several times without losing its power. Cyanide of potassium is a deadly poison; contact with any sore or cut is extremely dangerous, and inhaling its vapor is sudden death.

2566. To Remove Stains of Aniline from the Hands

2566.    To Remove Stains of Aniline from the Hands. The best way to remove such stains from the hands is to either wash them with strong alcohol, or what perhaps is more effectual, to wash them with a little bleaching powder, and finally with alcohol.