Method of preparation of compositions for an amalgam

A process for making dental amalgam for use as a dental filler characterized by the preparation of a mixture comprising a treated silver composition and a silver-mercury compound, comprising:

• preparing the treated silver composition from metallic silver and tin of high purity by the steps of forming a homogeneous alloy of silver and tin, reducing the alloy to form a fine powder, reacting said powder with hydrochloric acid to remove the dissolved tin from the alloy thereby leaving solid particles of treated silver in the acid solution, the process of hydrochloric acid treatment being carried out several times on the solid particles until there is a noticeable color change in the solid particles from a dark grey to a yellowish brown color, filtering the yellowish brown solid particles and washing them several times with warm water to remove all traces of the acid, and drying the particles to form the treated silver composition;
• preparing said silver mercury compound from granules of metallic silver of high purity and mercury by the steps of reacting either a mixture of the granules and the mercury with nitric acid to form a nitrate solution, or reacting the silver granules and mercury separately with nitric acid each to form separate solutions, which two solutions are subsequently mixed to form a combined nitrate solution, diluting the nitrate solution by adding water, and introducing metallic copper of high purity which results in a precipitate of a silver mercury composition, which is filtered and washed several times with warm water to remove traces of acid and is then dried to result in the silver-mercury compound,
• and combining said mixture with mercury to form a dental amalgam that is devoid of harmful free mercury.