Essais chimiques d’eckartshausen

Consecutive Experiments on the Decomposition of Metals

Wet decomposition of noble metals

We take a noble metal that has been made spongy in a reverberatory furnace or that has been made suitable for decomposition by any other means, such as fine trituration, amalgam, then we cover it with our sulfur, prepared philosophically.

So after watering it with our , we put it at a gentle heat and we let it digest for some time.

The first phenomenon that follows is that the metal covered with its sulfur loses its luster and polish and appears as a colored, resinous body, which resolves on heat to a tenacious and sticky slurry, but which evaporates completely, in a vacuum, over medium heat.

If the transformation has been carried out properly, one can proceed to the separation of the constituent parts.

The operation changed the constituent parts of the metal by the difference in proportions; what was "bound" in the metal united with the solvent and separated it from binding parts. It is only by their affinity that these hold together and they must, therefore, like other bodies, be separated according to the laws of affinity.

But first of all it is necessary to separate the acid solution and the metallic sulfur again, so that the constituent parts, binding and bound, are freed from each other, according to their order.

The binding parts can be separated from the metals when the part bound or dissolved by the appropriate separation means is removed from the mixture.

The extraction is obtained as follows: when the pure metal is dissolved by the metallic sulfur with which it has been covered, it is poured into distilled water with salt, ammonia which absorbs what is sulfur and phosphorus. The residue contains the binding parts of the metal, ie. to d. talciform and coloring earth. This must be leached and often desugared with distilled water.

On the noble metals, which have in their fundamental mixture the coloring earth and similar to talc, a solution of spirit of salt and spirit of saltpeter is poured which absorbs the earth.

In any metal which contains only talc-like earth, such as zinc, tin, etc., only a solution of nitric acid is needed; talciform earth, by its decomposition into an alkaline salt, is rejected. When the deposit is dried and sugared, a white earth is obtained which is slightly oily and soapy to the touch, which is very flammable.

When the desugar residue of the talciform coloring earth is put in a solution of mercury, in nitrogen acid, this earth dissolves in the acid. The salt unites with the mercury and settles with it at the bottom of the container.

The salt of this earth is obtained by extracting the mercury by distillation; the salt settles to the bottom of the container in the form of a red, flammable sediment. If one wants to separate phosphoric acid and metallic sulfur - or actual phosphorus - from the metal, both of which are dissolved, this solution must be slowly evaporated and the remaining urine salt covered with soot or dust. coal; by subjecting the whole to distillation we obtain the quantity of phosphorus which was in the metal and that which has been added to it. -The final residue is urine salt.