Mineral suspensions show Newtonian flow properties at lower solid concentration, but change into non-Newtonian regime as the solids content is increased. For Newtonian fluids viscosity is independent of shear rate, but for non-Newtonian fluids it varies with rate of shear. Therefore, measurement of viscosity at a shear rate, different from the process will be futile … Read more
It is important to have Assay Laboratory standards over a range of grades. This alone may preclude the material being sampled from serving exclusively for the preparation of standard material. One of the standards must have as close to an absolute zero value as possible. At least three and if possible five other standards should … Read more
Simplistically, nitrogen species oxidize the sulfide and solubilize some of the metal values. In essence, the silver, copper and less noble metals are dissolved in the leach. The slurry is screened, thickened and filtered. Two different solids are produced. First, sulfur pellets are recovered. Then, the insoluble fine leach residue, consisting primarily of lead sulfate, … Read more
Among the wide variety of modern surface chemistry analytical techniques, contact angle measurements still remain attractive for wetting characterization of solid surfaces. It is demonstrated that the contact angle value depends on the technique used when nonideal, heterogeneous and rough, solid surfaces are examined. Reagents and Materials Three different solid surfaces were used in the … Read more
The cementation of gold on to copper and zinc in ammoniacal solutions has been investigated using electrochemical techniques and conventional cementation experiments: Studies of cathodic reduction of Au(NH3)2+ have shown that the cathodic reaction can be expressed as: Au(NH3)2+ + e = Au + 2NH3 and the standard reduction potential, E°, has been estimated to … Read more