Abstract: Liquid treatment apparatus comprises at least two chambers being first and second chambers through which a fluid can flow. The two chambers are separated by at least one choke nozzle which has an entrance in the first chamber and an exit in the second chamber. The choke nozzle comprises a converging section at its entrance, a throat section, a backward-facing step immediately after the throat section, and an exit section at its exit wherein the exit section diverges from the step. Similarly constructed mixing nozzles may be included in the apparatus. The apparatus is especially useful in processes requiring a gas to be entrained in a fluid so that the gas is in the form of very small bubbles that do not tend to coalesce and flash off such as in the dissolution of gold and other precious metals from ore and in the removal of arsenic from an ore.

Abstract: Liquid treatment apparatus comprises at least two chambers being first and second chambers through which a fluid can flow. The two chambers are separated by at least one choke nozzle which has an entrance in the first chamber and an exit in the second chamber. The choke nozzle comprises a converging section at its entrance, a throat section, a backward-facing step immediately after the throat section, and an exit section at its exit wherein the exit section diverges from the step. Similarly constructed mixing nozzles may be included in the apparatus. The apparatus is especially useful in processes requiring a gas to be entrained in a fluid so that the gas is in the form of very small bubbles that do not tend to coalesce and flash off such as in the dissolution of gold and other precious metals from ore and in the removal of arsenic from an ore.

Abstract: Liquid treatment apparatus comprises at least two chambers being first and second chambers through which a fluid can flow. The two chambers are separated by at least one choke nozzle which has an entrance in the first chamber and an exit in the second chamber. The choke nozzle (1) comprises a converging section at its entrance (3), a throat section (4), a backward-facing step (5) immediately after the throat section (4), and an exit section at its exit (6) wherein the exit section (6) diverges from the step (5). Similarly constructed mixing nozzles (1) may be included in the apparatus. The apparatus is especially useful in processes requiring a gas to be entrained in a fluid so that the gas is in the form of very small bubbles that do not tend to coalesce and flash off such as in the dissolution of gold and other precious metals from ore in the removal of arsenic from an ore.

Abstract: Liquid treatment apparatus comprises at least two chambers being first and second chambers through which a fluid can flow. The two chambers are separated by at least one choke nozzle which has an entrance in the first chamber and an exit in the second chamber. The choke nozzle (1) comprises a converging section at its entrance (3), a throat section (4), a backward-facing step (5) immediately after the throat section (4), and an exit section at its exit (6) wherein the exit section (6) diverges from the step (5). Similarly constructed mixing nozzles (1) may be included in the apparatus. The apparatus is especially useful in processes requiring a gas to be entrained in a fluid so that the gas is in the form of very small bubbles that do not tend to coalesce and flash off such as in the dissolution of gold and other precious metals from ore in the removal of arsenic from an ore.

Abstract: This invention relates to a process for obtaining metal values, typically base metals, platinum or gold from a feed material. In a first step of the process of the invention, feed material containing metal values is ground to a particle size d90 of 100 microns or less to form an ultra fine pulp. In a second step of the process of the invention, the ultra fine ground pulp from the first step is oxygenated by pumping it in multiple passes through an in-line high shear static oxygenation device (30), while re-circulating it on a tank (28) or any other vessel. The process of the invention results in a significant reduction in the required leach time, improved recoveries, reduced cyanide consumptions, a steadier gold tail, as well as reduced capital and operational expenditure.

Abstract: This invention relates to a method of removing cyanide in the form of free cyanide (cyanide ions i.e. CN?) and weak acid dissociable cyanide (WAD) from an aqueous stream. WAD is cyanide complexed with metals such as Cu. The method finds particular application in removing cyanide from a tail stream from a carbon in leach (CIL) mining operation. The method of the invention is carried out by contacting an aqueous stream containing cyanide with carbon, under conditions wherein the Eh (oxygen reduction potential (ORP) measured in mV) of the aqueous stream is O or above. Advantageously the pH of the solution is buffered to from 7-9.

Abstract: This invention relates to a process for obtaining metal values, typically base metals, platinum or gold from a feed material. In a first step of the process of the invention, feed material containing metal values is ground to a particle size d90 of 100 microns or less to form an ultra fine pulp. In a second step of the process of the invention, the ultra fine ground pulp from the first step is oxygenated by pumping it in multiple passes through an in-line high shear static oxygenation device (30), while re-circulating it on a tank (28) or any other vessel. The process of the invention results in a significant reduction in the required leach time, improved recoveries, reduced cyanide consumptions, a steadier gold tail, as well as reduced capital and operational expenditure.