Gold, as a global hard currency, its purification technology has always been the core issue of the
precious metal processing industry. As a contemporary mainstream gold refining technology,
electrolysis is reshaping the industrial pattern of precious metal purification by virtue of its high
efficiency, environmental protection, high purity and other advantages. In this paper, we will
analyze the technical principle of electrolytic gold extraction, process characteristics and industry
applications, to provide practitioners with systematic technical reference.
Electrolytic gold extraction technology principles and
process framework
The core principle of gold electrolysis is based on electrochemical redox reaction. Through the construction of
a specific electrolysis system, the gold-containing raw materials in the anode oxidation reaction, the gold element
in the form of ions into the electrolyte, and then in the cathode surface reduction for high-purity gold deposits.
The entire process requires precise control of three main elements:
Electrolyte System
Usually, chloroauric acid (HAuCl₄) is used as the main electrolyte, and hydrochloric acid is used as the acidic
medium, and the proportioning concentration directly affects the ion migration efficiency. The new
composite electrolyte can improve current efficiency by more than 15% by adding surfactants.
Electrode material selection
The anode mostly adopts titanium-based platinum-plated electrode, which is both conductive and
corrosion-resistant; the cathode is made of high-purity titanium plate or 316L stainless steel, and
the surface roughness needs to be controlled at Ra ≤ 0.8 μm, which ensures the uniform
deposition of gold layer.
Process parameter control
Current density: conventional range 0.5-1.5A/dm², too high to produce dendritic structure.
Temperature gradient: Maintain 45-65℃ range, cooperate with circulating filtration system.
Pole spacing control: dynamically adjust the 3-8cm spacing to prevent short-circuit
Typical process flow decomposition
Raw material pretreatment stage
The gold-containing waste materials (electronic scrap, jewelry trimmings, mine rough gold, etc.) are graded
and crushed to 80-200 mesh, and then dissolved in nitric acid - aqua regia system, and then initially
enriched by activated carbon adsorption or solvent extraction. The key point is to control the pH value
of the dissolving solution in the range of 1.5-2.5 to ensure that the gold ions are fully dissociated.
Electrolysis refining process
Equipped with special electrolysis tank, adopting multi-stage series power supply mode. The anode area is
loaded with crude gold plates (purity ≥95%), and the cathode area is placed with titanium templates. A
single electrolysis cycle takes about 48-72 hours, and the thickness of the cathode deposition layer can
reach 2-3mm, after stripping, more than 99.99% high purity gold is obtained.
Tail liquid treatment system
Innovative use of ion exchange resin + electrodeposition combination process, so that the concentration of
residual gold ions in the electrolysis waste liquid is reduced to less than 0.1ppm. The recovered precious
metal dust is returned to the previous process after press-filtering and drying, realizing the closed-loop
utilization of resources.
Technical Advantages and Industry Applications
Compared with the traditional fire refining, electrolysis has significant advantages:
Purity breakthrough: the purity of finished gold can reach 99.999%, which meets the aerospace-grade
material standards.
Reduced energy consumption: unit energy consumption is reduced by 40% compared with the thermal
method, and the cost of gold treatment per ton is reduced by 25%.
Environmental protection upgrade: 80% reduction of exhaust gas emission and zero wastewater discharge.
High degree of automation: PLC control system realizes real-time monitoring of process parameters.
Current technology has penetrated into many fields:
Precious metal regeneration: treatment of gold-plated contacts in waste circuit boards, with a recovery rate of over 99.5%.
Jewelry Finishing: Preparation of ultra-thin gold foil (thickness ≤ 0.1μm) to enhance the value of the jewelry process.
Electronic industry: production of semiconductor bonding alloy wire to ensure the reliability of microelectronic devices.
Financial reserves: industrialized mass production of central bank-grade standard gold ingots.
Process optimization direction and risk avoidance
Despite the obvious advantages of the electrolysis method, the following technical bottlenecks still need to be noted:
Impurity interference: silver, copper and other associated metals are easy to co-deposited in the cathode, the
need to develop selective deposition of film technology
Equipment corrosion: the impact of strong acid environment on the life of the electrode, is testing ceramic-based
composite electrode materials
Energy consumption optimization: through pulse electrolysis technology, it is expected to reduce energy
consumption by 20%.
It is recommended that the production unit establish a three-level quality control system:
① Spectral analysis of raw materials → ② On-line monitoring of electrolysis process → ③ Rapid XRF inspection of finished products.
Industry Development Trend Outlook
With the breakthrough of new nano-electrode materials, the future electrolytic gold extraction technology will show three major trends:
Micro-reactor technology: development of modular electrolysis unit to realize distributed purification
Digital twin system: build process parameter database, dynamically optimize current efficiency through AI algorithm
Green process upgrading: bio-electrolysis technology is expected to replace chemical solvents and promote zero-pollution
production.
Gold electrolysis technology not only revolutionizes the traditional purification method, but also promotes the transformation
and upgrading of the precious metal industry chain. For practitioners, mastering the details of the process and continuous
technological innovation will be the key to grasping the market opportunities. With the enhancement of clean production
requirements, the intelligent and low-carbon electrolysis system will surely become the new benchmark of the industry.