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Click to add WeChatIn the previous article, we introduced the process, equipment, mineral processing process and advantages of desorption electrolysis. In this article, we will introduce the problems and solutions encountered in the desorption electrolysis of gold mines, such as how to control the reaction temperature and pressure to increase the gold extraction rate during the desorption electrolysis of gold mines?
In fact, in the desorption electrolysis process, controlling the reaction temperature and pressure to increase the gold extraction rate requires comprehensive consideration of many factors and taking a series of precise control measures. Some specific methods are introduced as follows:
Steam heating: The desorption electrolysis equipment can be heated by steam jacket or steam coil. Steam has the characteristics of large heat capacity and stable temperature, and can provide heat for the reaction more evenly. By adjusting the flow and pressure of steam, the heating speed and temperature can be accurately controlled. For example, in some large gold ore dressing plants, the high-pressure steam generated by the boiler is used to control the amount of steam entering the jacket or coil through the steam regulating valve, so that the desorption electrolysis temperature is stably controlled between 120℃-150℃.
Electric heating: For small desorption electrolysis systems or those with extremely high temperature control accuracy requirements, electric heating elements such as heating rods and heating wires are good choices. Electric heating has the advantages of fast heating speed and high temperature control accuracy, and the temperature can be accurately set and adjusted by the temperature controller. If an intelligent PID temperature controller is used, the power of the electric heating element can be automatically adjusted according to the deviation between the set temperature and the actual temperature, so that the temperature fluctuation range is controlled within ±1℃, ensuring that the gold extraction process is carried out in a stable high-temperature environment.
Thermocouples: Thermocouples are installed at different positions of the desorption electrolysis cell to monitor the temperature of the solution and the wall of the equipment in real time. Thermocouples can convert temperature signals into electrical signals and transmit them to the temperature display instrument and control system. Once the temperature exceeds the set range, the control system will immediately issue a command to adjust the power or steam flow of the heating equipment to achieve precise temperature control.
Temperature sensor: In addition to thermocouples, temperature sensors such as thermal resistors can also be used as auxiliary monitoring means. Thermal resistors have the characteristics of high precision and good stability, and can more accurately reflect temperature changes. Multiple temperature sensors are distributed at different depths and positions in the electrolytic cell, which can obtain more comprehensive temperature information and provide more accurate data support for temperature control.
Heating stage: In the initial stage of desorption electrolysis, it is necessary to quickly increase the temperature to a certain range to promote the desorption reaction. At this time, the heating power or steam flow rate can be appropriately increased to make the temperature rise rapidly. However, it should be noted that the heating rate should not be too fast to avoid thermal shock to the equipment, affecting the equipment life and gold extraction effect. Generally speaking, it is more appropriate to control the heating rate at 5℃-10℃/min.
Stable stage: When the temperature reaches the set working temperature, the temperature should be kept stable. According to the thermal effect of the reaction, adjust the heating amount in time. If the reaction is an exothermic reaction, the heating power may need to be appropriately reduced; if it is an endothermic reaction, the heating amount may need to be increased. Through precise temperature regulation, ensure that the temperature fluctuation does not exceed ±2℃ during the entire desorption electrolysis process to maintain the optimal thermodynamic conditions of the gold extraction reaction and improve the gold extraction rate.
Cooling stage: After the reaction is completed, the temperature needs to be slowly cooled to avoid gold re-adsorption or equipment damage due to a sudden drop in temperature. The heating power can be gradually reduced or the steam valve can be closed to allow the equipment to cool naturally. It can also be cooled by passing cooling water, etc., but the cooling rate must be controlled within a reasonable range, generally not exceeding 5℃/min.
Pressure regulating valve: installed on the pipeline of the desorption electrolysis system, automatically adjusts the valve opening according to the set pressure value, controls the flow of gas or liquid, and thus stabilizes the system pressure. For example, a pneumatic diaphragm pressure regulating valve is used to accurately adjust the amount of gas or liquid entering the system by receiving the signal of the control system, and the pressure is controlled within the range of 0.3MPa-0.5MPa to meet the pressure requirements of gold extraction.
Safety valve: As a safety protection device, when the system pressure exceeds the set safety pressure value, the safety valve automatically opens to release part of the gas or liquid to prevent the system pressure from being too high and causing a safety accident. The starting pressure and return pressure of the safety valve need to be reasonably adjusted according to the design pressure and working pressure of the desorption electrolysis system. Generally, the starting pressure is set to 1.1-1.2 times the working pressure.
Pressure gauge: Install pressure gauges at key positions of desorption electrolyzers and pipelines to display system pressure in real time. Operators can observe the readings of the pressure gauge to detect abnormal pressure in time. At the same time, the readings of the pressure gauge can also be used as feedback signals of the pressure control system to provide a basis for pressure regulation.
Pressure sensor: A pressure sensor is used to convert the pressure signal into an electrical signal and transmit it to the control system. The pressure sensor has the characteristics of high precision and fast response speed, and can more accurately monitor small changes in pressure. The control system automatically adjusts the opening of the pressure regulating valve according to the signal from the pressure sensor to achieve precise control of pressure.
Desorption stage: During the desorption process, appropriately increasing the pressure is conducive to promoting the replacement reaction between anions and Au(CN)₂⁻ on the gold-loaded carbon, thereby increasing the desorption rate of gold. Generally speaking, the pressure in the desorption stage can be controlled between 0.4MPa-0.5MPa. By adjusting the pressure regulating valve, the system pressure is gradually increased so that the desorption reaction can be carried out under a suitable pressure environment.
Electrolysis stage: During the electrolysis process, the stability of pressure is crucial to the deposition and extraction of gold. Excessive pressure may cause problems such as solution splashing and electrode damage, while too low pressure may affect the migration and deposition efficiency of gold ions. Therefore, the pressure in the electrolysis stage should be maintained within a relatively stable range, usually 0.3MPa-0.4MPa. During the electrolysis process, pay close attention to pressure changes, adjust the pressure regulating valve in time, ensure pressure stability, and create good conditions for the electrolytic deposition of gold.
In the desorption electrolysis process of gold ore, the accurate control of temperature and pressure is like installing a "stabilizer" for the effective operation of gold ore refining. By scientifically and rationally implementing the above methods, gold mining companies can not only improve gold production and quality, but also achieve a leap in resource utilization efficiency and economic benefits.
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