Hydrometallurgy
DETACLAD in Hydrometallurgy Hydrometallurgical processes are replacing many of the less efficient pyrometallurical methods for extracting valuable metals from ore. Detaclad® Plate makes construction of the new process equipment economically and technically viable.
Titanium Clad, High Pressure Acid Leach Autoclave
Acid leaching of minerals has typically been open to the environment. Frequently, heap leaching is simply achieved by distributing a leaching acid solution over a pile of crushed mineral and collecting the pregnant liquor runoff.
More sophisticated techniques have been laboratory tested, piloted and commercially used for decades. Some large scale, pressure acid leach systems designed to dissolve metal from ore have been successful for many years. They may use a brick lined and lead membrane protected steel pressure vessel to withstand the heat and acid attack at elevated pressures needed to support high throughput ore leaching production. This system is common in gold ore processing in Nevada. A solvent extraction process and electro-winning are generally used to complete the metal recovery. The gold autoclaves are Pressure Acid/Oxygen Leach.
Nickel ore has typically been smelted in furnaces. Pressure Acid Leaching (PAL) has proven to be a more energy efficient beneficiation technique for the extraction of nickel and other metals. Further, environmental impact is more easily managed with PAL technology. One commercial PAL plant, located in Cuba, has been successfully producing nickel since the late 1950s.
Several projects were developed in the 1990s to use the PAL system for beneficiation of laterite/limonite ores. All three projects are located in Australia. Temperatures and pressures are higher than in the gold autoclaves, creating significant problems for the traditional lead-brick system. The Australian, PAL autoclaves, all use explosion clad steel fabrication. Titanium is required in all parts of the system to resist the hot sulfuric acid. In high-pressure areas the equipment is fabricated from steel plate integrally clad to titanium.
A chart of the projects currently using titanium explosion clad, fabricated equipment follows. In addition to the large heavy wall autoclaves other equipment fabricated from Detaclad® include: heaters, flash tanks and mixers.
The most recent project to specify and order Detaclad® equipment is the Goro Project developed by Inco International, located in New Caladonia. The three autoclaves for this project are 4.3 m diameter, 26 m long and 118mm thick.
Other high pressure acid leach circuits using Detaclad® are being considered for gold and copper ore beneficiation. Concerns about the use of titanium in an oxygen rich environment have been addressed and most pundits are satisfied.
Detaclad® is not restricted to PAL circuits but can have technical and economical benefit anywhere bi-metallic properties can serve multiple demands. Related areas of interest can be found in “Primary Metal Melting” and “Electrochemical Processing”.
Additional Resources
Data Sheets & Brochures
Specifications for clad plate
Publications and References
Metal Types
| NASDAQ: BOOM
