Xstrata Technology are specialists in leaching, oxidation and engineering design, and have considerable operating experience gained within Xstrata’s own leaching operations.
The HyperSparge™ has been developed by Xstrata as part of an extensive research and development effort to improve the robustness and efficiency of oxygen and air injection in their own operations. HyperSparge™ units are installed in several of Xstrata’s own operations.
The HyperSparge™ is a gas sparging technology, designed for the injection of gases such as air or oxygen into a process slurry. In contrast to low pressure sparge rings or sparge pipes, the HyperSparge™ operates under mild pressure, and uses an alloy steel injection lance fitted with a hard wearing ceramic nozzle to inject a concentrated supersonic jet of gas into the process solution or slurry. The supersonic gas jet enters the process stream at velocities in excess of 400 m/s, creating a region of very high local shear, resulting in very efficient mass transfer.
The HyperSparge™ is a complete gas injection technology, consisting of several sub assemblies that are designed for safe live insertion and removal of the sparger, so that process downtime is minimised. The HyperSparge™ is inserted into the process through a nozzle in the side of the vessel, at waist height, so that the main components of the The HyperSparge™ are located outside the vessel for ease of access and maintenance. The HyperSparge™ can be removed for routine maintenance without any need to stop the process or empty the process vessel, and maintenance takes less than 15 minutes.
Xstrata Technology engage in ongoing research and development to continuously improve all of their process technologies, and have dedicated testing and pilot plant facilities to help clients in evaluating their oxidation and aeration requirements.
Xstrata Technology can provide a wide range of support engineering services, commissioning, training and post commissioning operational support.
Gas Injection at Supersonic Velocity
The HyperSparge™ injects air or oxygen into the process slurry or solution at supersonic velocities. This is achieved using a hard wearing ceramic jet nozzle designed to maximise the thrust of the gas stream at the point of injection. The unique nozzle profile differs from other sparging technologies by accelerating the gas stream to supersonic velocities, resulting in very high rates of shear at the pint of injection. These high local shear rates dramatically improve the gas-liquid interfacial area, resulting in efficient and reliable gas mass transfer.
The HyperSparge™ is designed to be inserted through multiple locations on the circumference of the process vessel. Supersonic gas injection at multiple points results in a series of concentrated gas jets that contact the process slurry in severals zones of very high shear. Oxygen mass transfer within these high shear zones is rapid and efficient, with minimal loss of oxygen to exhaust gases, and full use is made of the process vessel.
The HyperSparge™ nozzle operates under conditions of choked flow. The gas flowrate within the HyperSparge™ is self regulating, maintaining a constant volumetric flow profile at varying line pressures. Variations in gas delivery pressure will not adversely affect the operating performance of the sparger. Process control is simple, with line pressure the only variable that requires monitoring or control.
High gas injection velociities ensure the sparger nozzle is self cleaning, and the ceramic nozzle construction ensures a long nozzle life, with extremely low wear rates.
The nozzle has a robust ‘slip in’ design, which eliminates any treaded components within the slurry, ensuring a trouble free change out of nozzles when required. The external mounting arrangement for the HyperSparge™ means that maintenance is simple, with no process downtime and no requirement to empty or enter the process vessel.