In the field of precious metal refining, silver electrolysis process, as the core means of obtaining
high purity silver (99.99% or above), has a direct impact on the utilization rate of resources and
added value of products. With the deep integration of industrial Internet of Things (IoT), advanced
sensing technology and automation equipment, modern silver electrolysis refinery is experiencing
the transformation and upgrading from “experience-driven” to “data-driven”. In this paper, from the
process optimization, intelligent control, equipment upgrading and other dimensions, systematic
analysis of silver electrolytic refining automation technology path and implementation strategy.
Reconstruction of silver electrolytic refining process
1. Electrolyte system innovation
Dynamic formula control: adopting silver nitrate-nitric acid two-component electrolyte, real-time
control of nitric acid concentration (3-8g/L) and silver ion concentration (80-120g/L) through on-line
conductivity meter (accuracy of ±0.5μS/cm) and pH sensor (±0.05), to ensure that the current
efficiency stabilizes at more than 98%.
Impurity removal system: integrated cyclone electrowinning device and membrane filtration unit,
the removal rate of lead, bismuth and other impurities is increased to 99.7%, and the silver content
of anode mud is reduced to below 0.8%.
2. Breakthrough in electrolyzer structure
Multi-stage countercurrent electrolysis design: 8 tanks in series configuration, single tank voltage
gradient control (0.3-0.5V), cathode deposition rate up to 1.2mm/h.
Magnetic field assisted technology: permanent magnet array (0.2-0.5T) embedded in the bottom
of electrolyzer, optimizing silver ion migration path through Lorentz force, DC power consumption
reduced by 18%.
3. Intelligent Polar Plate Processing
Fully-automatic silver stripping unit: six-axis manipulator equipped with flexible suction cups,
positioning accuracy ±0.05mm, cathode silver stripping efficiency up to 50 pieces/hour, silver
powder loss rate <0.3%.
Intelligent cleaning line for anode frame: high-pressure water jet (350Bar) with visual inspection
system, residual electrode processing time is shortened to 20 minutes/batch.
Core structure of automation control system
1. Central control platform
Build a two-tier architecture of SCADA (data acquisition and monitoring system) + MES (manufacturing
execution system) to realize:
Real-time monitoring: 2000+ sensors collect parameters such as current density (200-400A/m²),
temperature (30-45℃), liquid level, etc., with data refreshing frequency of 1 second/time.
Dynamic regulation: automatic adjustment of rectifier output based on fuzzy PID algorithm, voltage
fluctuation range compressed from ±5% to ±0.8%.
2. Intelligent electrolysis management
Short-circuit warning system: Distributed current sensors (accuracy ±0.1A) can locate the
short-circuit point within 0.3 seconds, increasing fault response efficiency by 90%.
Deposition quality prediction: LSTM model integrating electrolyte composition, current efficiency
and temperature data, realizing precise control of silver crystal size (20-50μm).
Energy optimization module: automatically increase current density by 15% during valley power
hours, reducing overall power cost by 22%.
3. Digital twin application
Process simulation: establish a three-dimensional fluid dynamics model of the electrolyzer, optimize
the liquid distribution method so that the difference in silver ion concentration is <2g/L.
Equipment health management: Predicting pump and valve failures through vibration spectrum
analysis, and changing the maintenance cycle from passive overhaul to predictive maintenance.
Technical upgrading of key equipment
1. Intelligent electrolytic cell set
Titanium-based coating anode: IrO₂-Ta₂O₅ composite coating is adopted, extending the service life
to 5 years and lowering the overpotential of oxygen precipitation by 300mV.
Flexible cathode system: Stainless steel cathode plate surface laser weaving treatment (roughness
Ra 0.4μm), silver adhesion strength increased by 40%.
2. Electrolyte purification equipment
Continuous filtration unit: multi-layer sintered titanium cartridge (precision 0.5μm) to achieve the
removal rate of suspended solids >99.9%.
Electrochemical regeneration unit: selective oxidation of organic additives, nitric acid replenishment
is reduced by 60%.
3. Environmental protection treatment unit
NOx treatment: two-stage alkali washing + SCR catalytic reduction, exhaust gas NOx emission <30mg/Nm³.
Silver recovery system: cyclone electrowinning + electrostatic adsorption combination process, the
concentration of silver ions in wastewater is reduced to below 0.05mg/L.
Production efficiency and environmental value
1. Economic efficiency enhancement
Optimization of straight rate: silver electrolysis straight rate increased from 97.5% to 99.2%, with an
annual output of 1,000 tons, the annual revenue increase of more than 25 million yuan.
Energy consumption index: DC power consumption for tons of silver has been reduced to 1100kWh,
down 25% compared with the traditional process.
Labor cost: the automation of the whole process reduces the number of operators by 70%, and the
per capita production capacity exceeds 8 tons/year.
2. Environmental benefits breakthrough
Hazardous waste reduction: the amount of anode sludge generated is reduced by 55%, and the annual
hazardous waste disposal cost is reduced by 5 million RMB.
Carbon emission reduction: the proportion of green power application reaches 40%, and carbon emission
per ton of silver is reduced to 0.8t (industry benchmark 1.5t)
Resource recycling: the utilization rate of electrolytic waste liquid regeneration reaches 98%, and the
consumption of new water is reduced by 85%.
Future technology evolution direction
1. Deep integration of technology
Development of “electrolysis-finishing casting-inspection” integrated unit, realizing continuous
production of 9999 silver ingots.
Experimenting with super gravity field electrolysis technology to increase the deposition rate
to 2mm/h.
2. Intelligent sensing upgrade
Deploying fiber optic silver ion concentration sensors to shorten the detection response time to 5 seconds.
Introduced X-ray diffraction on-line analyzer to monitor silver crystallization orientation in real time.
3. Green Energy Coupling
Constructing a flexible power supply system of photovoltaic, energy storage and electrolysis, and
increasing the penetration rate of green power to 60%.
Developed a proton exchange membrane electrolysis hydrogen cogeneration plant, with by-product
hydrogen used in the reduction process.
4. Digitalization of the whole chain
Apply blockchain technology to realize the traceability of the whole process of “mine-electrolysis-terminal”.
Developed a digital passport system to record 200+ process parameters of each silver ingot.
Conclusion
The intelligent transformation of silver electrolysis and refining is essentially to reconstruct the material flow
and energy flow through the data flow, and to realize a qualitative breakthrough in the three dimensions of
purification efficiency, resource utilization and environmental friendliness. With the deep penetration of 5G
communication, digital twin, clean energy and other technologies, the future silver electrolysis plant will
present a new form of “process self-adaptation, zero-intervention production, and zero-emission”. Driven
by the scarcity of precious metal resources and the global carbon neutrality goal, intelligent electrolytic
refining technology is becoming the core engine to promote the high-quality development of the
non-ferrous industry.