Abstract: A cylindrical tank (12) is formed from stainless steel plates. Proximate an open top end (17) of the tank (12) are four evenly spaced mixing assemblies (20). An intake pipe (22) is positioned with an open end (38) below the surface of a biological conversion medium (16) to allow a pump (28) to draw the medium (16) into a receiving box (24). A downcomer (26) merges with the receiving box (24) in order to allow the medium (16) to be injected with a biological conversion component such as air through an inlet pipe (34). The medium (16) and the injected component then pass through a static in-line mixer (30) which thoroughly mixes the medium (16) with the component and creates a multitude of finely-divided air bubbles for circulation and feeding of the medium (16) throughout the tank (12).

Abstract: A cylindrical tank (12) is formed from stainless steel plates. Proximate an open top end (17) of the tank (12) are four evenly spaced mixing assemblies (20). An intake pipe (22) is positioned with an open end (38) below the surface of a biological conversion medium (16) to allow a pump (28) to draw the medium (16) into a receiving box (24). A downcomer (26) merges with the receiving box (24) in order to allow the medium (16) to be injected with a biological conversion component such as air through an inlet pipe (34). The medium (16) and the injected component then pass through a static inline mixer (30) which thoroughly mixes the medium (16) with the component and creates a multitude of finely-divided air bubbles for circulation and feeding of the medium (16) throughout the tank (12).

Abstract: A process for the biological oxidation of sulfide in sulfide-containing ore. Preferably, the ore is then subjected to cyanide leaching. The resulting leach tail solution can be subjected to cyanide precipitation, employing ferric sulfate which is generated during the biological oxidation step of the process. Furthermore, a process for efficiently aerating the ore slurry during the biological oxidation step is provided.

Abstract: A method for obtaining a smoking material additive which is a smoke-aroma precursor comprises the steps of removing surface gum, preferably surface gum only, from Nicotinia plant leaves or flowers and subjecting the gum to a partition or purification process whereby a diterpene fraction constituting the said precursor and a fraction containing undesirable lipids are obtained, the latter fraction being discarded. The gum may be removed by solvent washing, suitably with chloroform. The partition or purification step may be a two-phase solvent partition process, for example using a hexane/aqueous methanol system.