Design Of A Dissolved Oxygen Monitoring Instrument In Cyanide Process

Oxygen dissolved into the water by the chemical reaction or biochemical effects is called dissolved oxygen (DO). In the cyanide process nowadays, Oxygen is one of the main essential factors. It directly affects the leaching rate of gold, cyanide consumption and the damages of the environment and so on. However, not any dissolved oxygen monitor currently exists for this harsh environment which is full of complex effects. Therefore, it is necessary to design the instrument of high-sensitivity and real-time for continuous oxygen monitoring for a long time.Based on fluorescence quenching detection principle, a new DO monitoring technology is designed by integrating the electronics, mechanics, optics and computer technology. The instrument includes optical and electrical detecting module, precise amplification and signal processing module, and real-time communication module and so on, resistant to corrosion and wear. The instrument achieves functions of detection of weak fluorescence signal and real-time communication for monitoring.The results of experiments in the lab show that:the system response time was about30s, the detecting accuracy was up to0.06mg/L in the range of0～11mg/L. The results are less than2%change during2months detected. Test results basically unchanged during the change of the pH value in the range of0～12. Carbon dioxide, hydrogen sulfide, sulfur dioxide and other gases has effects within0.05%. The instrument has advantages of high accuracy, fast response, good stability and strong anti-interference.The results of experiments in mine field in Shandong province show that:It can work in the harsh environment for a long time, and the results are reliable. It has good applicability and stability. Besides, it is small in size, which has great application prospects in fields of long time oxygen monitoring.