This includes the equipment used in the recently developed Pre-Coat conditioning of the clarifier leaves, without which the present perfection of clarification would not be possible. Details of this leaf are shown with a drawing and description of the complete unit. Long experience has shown that such clarification is most effected in low pressure vacuum leaf filters of special design to facilitate handling and changing covers. It should move all suspended solids from the pregnant solution, when those colloidal suspensions invisible to the naked eye. In Merrill Crowe, perfect clarification is probably the most important factor in obtaining efficient precipitation.

OXYGEN AND CARBON DIOXIDE GASES DISSOLVED IN THE SOLUTION.

SCALE FORMING COMPOUNDS, chiefly the carbonates and sulphates of lime.

This formation occurs slowly and is almost completely prevented by clarifying and precipitating simultaneously. SUSPENDED PRECIPITATES, as above defined, which may continue to form in the solution AFTER clarification.These combined solids should be completely removed by efficient clarification.

SUSPENDED SOLIDS, such as ore slime and precipitates of calcium carbonate, with hydrates of aluminum, magnesium and iron, present in the pregnant solution before clarification.The most important of these properties are listed below: Efficient Merrill Crowe precipitation of gold and silver is dependent upon the proper control of certain physical and chemical properties of the solution.

Gold precipitation with copper