Hydrometallurgical treatment of metal bearing materials, such as copper ores, concentrates, and other metal bearing materials, has been well established for many years. Typically, conventional hydrometallurgical processes for copper recovery involve leaching metal bearing materials with an acidic solution, either atmospherically or under conditions of elevated temperature and pressure. The resultant process stream—the pregnant leach solution—is recovered, and a processing step such as solution extraction is used to form a highly concentrated and relatively pure metal value containing aqueous phase. One or more metal values may then be electrowon from this aqueous phase.
Leaching under atmospheric conditions in a heap leaching operation may comprise placing an acidic leaching solution into a collection of ore referred to as a heap to liberate metal values from the ore. Heap leaching may thus involve the use of a leaching solution distribution system, which is typically a large network of pipes or other conduits. The pipes or other conduits may have nozzles or other orifices that are designed to emit leaching solution at a particular target rate.
Leaching solution may be sourced from a variety of locations. Fresh acid and/or water may be used as well as acid and/or water that is recycled or reclaimed from other metal value recovery processes. Accordingly, particulates or other solid phase impurities and/or liquid organic phase containments (also referred to as “crud”) may be contained within the leaching solution. Over time, crud may occlude or otherwise obstruct the nozzles and/or orifices of the leaching solution distribution system. Such obstruction restricts leaching solution flow. Improper leaching solution flow is detrimental to metal value recovery processes.
Nozzle and/or orifice occlusion (also referred to as “plugging”) may cause an increase in pressure in the pipes of a leaching solution distribution system.