High-rate Gold Loaded Carbon Stripping Column and Electrowinning Cell Plant
1.1 Elution
CN- or OH- dissolved in desorption solution is easier than Au(CN)2- to be absorbed by the activated carbon which causes Au(CN)2- absorbed on loaded carbon is replace by CN- or OH- and the reversible balance of of gold adsorption is broken. This processing is named as gold desorption (elution, stripping). The reaction formula is below:
Gold is stripped out of loaded carbon by increasing cyanide concentration, alkalinity, temperature, pressure or adding organic solvents, etc. Comparing other methods, it is the lower production cost that temperature and pressure are improved. If the working temperature is 150oC and working pressure is about 5.5 bar, the elution rate is improved by several times and the cycle time is reduced to be fraction of that one of normal pressure cycle.
1.2 Electrowinning
Gold exists as Au(CN)2- in the pregnant solution produced in the adsorption circuit. The pregnant solution is sent to the electrowinning cell for electrochemical reactions. The reactions are as below:
Cathode formula:
Au(CN) 2-+ e → Au+2CN-
Ag(CN) 2-+ e → Au+2CN-
2H2O +2e → H2+2OH-
Anode formula:
4OH- - 4e → O2+2H2O
CN-+2OH- - 2e → CNO-+H2O
2CNO- +4OH- - 6e → 2CO2+N2+2H2O
When the electrowinning solution temperature grows up, the deposition speed of gold becomes faster and the deposition efficiency is increasing as well.
1.3 Elution - Electrowinning Circuit
Elution and electrowining circuits form a packaged integrated pressure strip (IPS) system which works under high temperature and pressure so the elution circuit cancels the heat exchanger which is used in Zadra system. The pregnant solution ahs high temperature which is favorable to the electrowinning cell.
- High temperature, high pressure, cyanide-free and elution controlled automatically bring out the advantages of high efficiency, low consumption, and quick cycle.
- High efficiency: the elution rate can be more than 96% while the gold grade of the loaded carbon reached more than 3000g/t. The grade of barren carbon can be reduced by 3-4 times than that of the conventional system.
- Quick cycle: the working temperature of the system is 150ºC so that elution is quick and the stripping duration is shorter that total cycle time is about 10 to 13 hours.
- Low consumption: the elution devices and electrowinning equipment compose a integrated system. The temperature of every section of the whole system is same so that the heat exchanger is no need. The total power consumption is only 1/2-1/4 of the value of the conventional system because heat energy is recycled fully.
- Cyanide-free: no sodium cyanide is fed to prepare stripping solution to realize low costs and no pollution.
- Gold recovery: high grade of gold sludge, no reverse electrowinning, easy to collect gold sludge.
- Automation: special liquid level control unit, temperature control unit and automatic control center.
- Safety: triple safety protection devices, i.e., self intelligent system, automatic rated pressure release system and safety valves.
- Long life: the material type of equipment, pipes, valves and instruments is stainless steel.
- Modular plant: the system is a modular plant which is easy for installation on the site. The small scale elution plant is containerized.
FAQ
1.What is the main business scope of your company?
HZE is a company with R&D center, design institute, manufacturing factories, installation and commissioning teams.Our customers are in the mining and mineral processing fields.Our major businesses include mineral processing EPC (engineering, procurement and construction), project consultation, engineering design, mineral processing equipment manufacturing, on-site installation, commissioning, staff training, customer project operation management, spare parts supply and technical support.Customers are free to choose any one or any combination of our services.
2.What are the outstanding advantages of your company?
The one-stop service of mineral processing engineering project and equipment is our core competitiveness.
The most important feature that HZE distinguishes itself from other engineering companies, design companies or consulting companies is that we are also an equipment manufacturer with a production plant of 50,000 square meters, and we have complete manufacturing rout and the related equipment.
HZE distinguishes itself from other equipment manufacturers by owning its own R&D center and engineering design institute.
HZE distinguishes itself from many mining machinery enterprises by possessing an expert team with members including not only senior engineers of the company, but also top Chinese technical experts, university professors and researchers.
3.What are the characteristics of your company's 3D design?
HZE not only uses 3D software to design equipment, but also uses 3D software to design process flow, pipeline, steel structure, auxiliary facilities, etc.Of the whole mineral processing project.We even use 3D design for equipment packaging, container packing and equipment instructions manual.This greatly improves the quality of equipment and engineering, shortens the construction period, facilitates technical discussion and evaluation, facilitates project management, improves construction safety and reduces project cost.
4.What are the service features of your company?
- Customers who whether buy our equipment, or entrust us with EPC, or require us to provide a certain service, cooperate closely with us to carry out specific operations and supervise our implementation throughout the process.
- HZE will try to understand the basic situation and needs of customers as detailed as possible before the sale, formulate a preliminary plan according to the specific situation of customers, and get unanimous opinions after communications and discussions with customers to determine the plan.
- We set up customer files for every customer who signed the contract with us and upload them to the Cloud where customers can also get an account and password.Customers can have all the documents, videos and pictures, technology, services, execution, operation, management and control, maintenance and so on related to the business.
- Whether it is in the process of general contracting, equipment manufacturing or providing some kind of service, we welcome customers to know about our implementation on the spot or through the network, and put forward requirements and opinions.
- We assist users who have used our products to formulate operation specifications and make suggestions on maintenance plans and spare parts inventories.In addition to routine on-site installation, commissioning and training, during the production period after we handing over equipment to customers for use, we often understand the equipment using situations through the network and provide guidance and training to customer management and operators.
- For the clients who have just start the mining business, we provide the opportunity of training and practice in China's mines for the clients' employees, until they are skilled in operation and maintenance.
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