Measuring potential in a pressure oxidation autoclave

压力氧化（POX）用于处理越来越多的金矿石，这些矿石在进行全矿直接氰化时导致金回收率差。这些“难熔”矿石通常由硫化物组成，如黄铁矿（FeS2）和毒砂（FeAsS），这些硫化物包裹着细小的金颗粒，使它们无法被氰化物所接触。然后，POX的作用是分解硫化物，从而将金释放出来供将来的氰化。POX通常在高压氧分压（150至700千帕）和高温（约220°C）下在称为高压灭菌器的压力容器中操作。在POX反应器中普遍存在的条件对下游处理的成功和最终金的回收至关重要。特别是，控制硫化物氧化是非常重要的，以确保氰化过程中硫化物矿物的充分分解和高金的提取。通常用于过程控制的一个变量是氧化浆料从POX反应器排出后的氧化还原电位（ORP）。然而，这种方法的缺点是不能反映反应堆的实际情况，因为测量也反映了与冷却过程相关的重大热化学变化。

Pressure oxidation (POX) is used to treat the increasing number of gold ores that result in poor gold recovery when subjected to whole-ore direct cyanidation. Typically these "refractory" ores consist of sulphides, such as pyrite (FeS2) and arsenopyrite (FeAsS), which encapsulate the small gold particles and render them inaccessible to cyanide. The function of POX then is to break down the sulphide, thus liberating the gold for future cyanidation. POX is typically operated at high oxygen partial pressures (150 to 700 kPa) and high temperature (ca. 220°C) in a pressure vessel known as an autoclave. The conditions prevalent in the POX reactor are critical to the success of the downstream processing and ultimate gold recovery. In particular, it is very important that sulphide oxidation be controlled to ensure adequate break down of the sulphide minerals and high gold extraction during cyanidation. One variable that is often used for process control is the redox potential (ORP) of the oxidized slurry after discharge from the POX reactor. However, this method has the drawback of not reflecting the actual conditions in the reactor, as the measurement is also a reflection of the significant thermo-chemical changes associated with the cooling process.