Gold in Sea Water.

New Zealand Graphic, Volume XXXVI, Issue 23, 9 June 1906, Page 7

Gold in Sea Water.

M. P. de Wilde. Professor at the University of Brussels, has taken up the study of the gold which is contained in sea-water. He proposes a new method of extracting it. A ton of sea-water is treated with four or live cubic centimetres of an acid and concentrated solution of chloride of tin. The whole of the gold is thus concentrated in the complex body known as purple of Cassius, which contains gold, tin, and oxygen. It is found that the purple body is fixed very strongly upon the flaky hydrate of magnesium which is set free in sea water when we pour in lime water. The hydrate falls to the bottom with the gold attached to it. The gold is set free by a cyanide of potassium solution (about 1 in 2900), thus forming a cyanide of gold. The metal can then be extracted by a number of well-known methods. Liversidge shows that when sea-water is sent in casks the wood causes the gold to precipitate, and thus none is found in the water. M. de Wilde made experiments at the seashore in France on the west coast, and found traces of gold in the water. He considers that much of the gold is thrown down to the sea bottom. and thus it escapes us. It will be remembered that Liversidge, Professor at the University of Sydney, found from Agr to Igr of gold per ten of sea-water from the coast of New South Wales.— "Scientific American.”