CESL process for medium temperature oxidation acid leaching of sulfide ore

1990, Ke Mingke (Cominco) Process Engineering Services Limited proposed a technique called the CESL (CESL the company name abbreviation full) [1], use of two leaching, including processed mineral brass low pyrite And chalcopyrite - bronze ore mixed mine. The first level is 150 °C The lower leaching solution is diluted with dilute sulfuric acid and a small amount of hydrochloric acid, and the leaching solution contains a chloride ion concentration of about 12g /L , 15~ 20g /LCu 2+ , Cu 2+ is a direct oxidant. The amount of acid added is controlled so that the final pH is 2.3 to 3.5 and copper is converted to basic copper sulfate. Second stage atmospheric leaching, leaching temperature 40 ° C Maintain a pH of 1.5~2 to dissolve the basic copper sulfate and minimize the entry of iron into the solution. Since the reaction is exothermic, no heating is required for both reactions. The leaching time of both sections is about 1 h . In the first stage of leaching, iron is converted to hematite, 90% of the sulfur is converted to elemental sulfur, and a small amount is sulfate. After extracting and evaporating a section of leachate, returning to a section of leaching, extracting copper by two-stage leaching solution, and electrowinning after stripping. The process is shown below. The recovery rate of copper in the whole process is about 99% . Extraction 1 and extraction 2 were combined with the extract 3 organic phase and washed together for stripping.

The CESL process is constantly evolving to accommodate different materials, and the flow chart has changed many times. It is estimated that investment in plant CESL process of production capacity of 200,000 t to $ 225 million, with half-scale fire plant. Production costs are estimated at 176~286 USD /t electrolytic copper.
References :
1.Cominco, Copper Hydrometallurgy Forum, 1998,

• Materials:

o Conductor: Cat6A UTP stranded, 24AWG, 7x0.2, bare copper

o Insulation: polyethylene with color marking on white cores

o Unshield: individual foil for each pair, with general ground wire

o Outer jacket and boots: PVC, CMX, CM, CMR, leaded and lead-free as well as LSZH versions are available

• Nominal outer diameter: 6.0 ±0.2mm

• Color code: BL/WH-BL, WH, GN/GN-WH or BR/BR-WH

• Cable colors: grey, others colors from RAL and Pantone are available

• Mechanical characteristics:

o Cable to plug tensile strength: 9kgsf (90n) minimum

o Minimum bending radius: 22mm

o Storage temperature: -20 to +80°C

o Durability: 750 mating cycles

o Plug housing: UL 94-V0, UL 94-V2 and polycarbonate

o Plug contact material: 50μ-inch gold plating over 100μ-inch nickel-plated copper alloy

o Fire performance: IEC 332.1, VW1, IEC 332.3 versions available depends on the jacket type

o Product length: 0.5 to 100m (optional)

• Electrical performance:

o Contact resistance: 20mΩ (maximum)

o Voltage: 75V (maximum)

o Dielectric strength: 1,000V/ 1 minute minimum RMS

o Current: 1.0A (maximum)

o Insulation resistance: 500MΩ minimum at 500V DC

o Performance test: 100% Patch Cord test for Cat6A, Cat6 and optional for Cat5E Patch Cord

• Certificates: ISO 9001:2001, ISO 14001, OHSAS 18001, UL and REACH

• RoHS Directive-compliant

• Packaging: 1 piece/bag

• Production capacity: 20,000 pieces/day

• Unit price: USD 1.5 to 5.0/piece

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