Yoko Pranolo

Separation of Cobalt and Zinc from Manganese, Magnesium, and Calcium using a Synergistic Solvent Extraction System Consisting of Versatic 10 and LIX 63

Abstract The Boleo leach solution contains large amounts of manganese (45 g/L), magnesium (25 g/L) and small amounts of cobalt (0.2 g/L) and zinc (1 g/L) in sea water. Due to the high manganese concentration, it is very difficult to separate cobalt and zinc from manganese, magnesium, and calcium using conventional solvent-extraction processes, which has led to the development of a synergistic solvent extraction (SSX) system consisting of Versatic 10 and LIX®63. By adding 0.4 M LIX 63 to 0.5 M Versatic 10, large synergistic shifts were obtained for cobalt (max. ΔpH50 4.24) and zinc (max. ΔpH50 1.62). After a single contact at pH 4.5, the extraction of cobalt was almost complete and that of zinc 80%. The extraction of manganese was 1.55%, and almost no magnesium and calcium were extracted, indicating excellent separation of cobalt and good separation of zinc from manganese, magnesium, and calcium. The SSX system was further optimized to reduce the co-extraction of manganese with the synthetic Boleo demonstration plant solution. It was found that with 0.33 M Versatic 10 and 0.30 M LIX 63, the SSX system composition approached optimum. After a single contact at pH 5.5, the extractions of cobalt and zinc were 93% and 70%, respectively, while the manganese concentration in the loaded organic solution was only 0.28 g/L. The extraction and stripping kinetics of cobalt and zinc were rapid. The SSX system was tested in two integrated pilot-plant trials with excellent results. Baja Mining has planned to implement the SSX circuit in their future Boleo plant.

The Recovery of Zinc and Manganese from Synthetic Spent‐Battery Leach Solutions by Solvent Extraction

Recycling zinc‐carbon spent batteries is receiving growing interest due to environmental concerns and also the large quantity involved. It would therefore be advantageous to develop a solvent‐extraction (SX) process for the recovery of zinc and manganese from spent zinc‐carbon battery leach solutions. Among the two systems considered, D2EHPA and Ionquest 801, the latter is a better choice in terms of metal separation and stripping. It was shown that two theoretical stages are needed for the extraction of iron and zinc with the system containing 30% (v/v) Ionquest 801 and 5% (v/v) TBP in Shellsol D70 at an A/O ratio of 1:1, pH 3.0, and 40°C. The extraction kinetics of iron and zinc were very fast, and their extractions reached 99% and 93% within one minute, respectively. Less than 1% of the manganese was extracted in two minutes. The stripping kinetics of zinc was very fast, with over 97% being stripped in 30 seconds. The selective stripping of zinc from iron could be achieved at pH 0.5. Iron cannot be stripped effectively with the stripping solution containing 40 g/L zinc and 170 g/L H2SO4. Thus, an organic bleed stream could be needed to strip the iron with 400 g/L sulphuric acid. A process flowsheet has been proposed for the recovery of zinc and manganese from spent zinc‐carbon battery leach solutions using the Ionquest 801/TBP system. The advantage of this process is that both pure zinc and manganese product solutions could be obtained.

Uranium Solvent Extraction and Separation From Vanadium in Alkaline Solutions

Quaternary amine could be used to extract uranium from alkaline leach solutions, but third phase formation prevented its application. In this paper, isodecanol was used as the modifier for Aliquat 336 in Shellsol D70 to extract uranium from a carbonate leach solution. The formation of third phase was eliminated. More than 98% of uranium was extracted using 3% (w/v) Aliquat 336 and 3% (w/v) isodecanol in Shellsol D70 from a carbonate leach solution containing 95 mg/L U and 25 mg/L V at pH 10.3 and room temperature in a single contact. The separation factor of uranium over vanadium increased with increasing pH of the auqueous solution and reached 280 at pH 11, indicating a good separation of the two metals. The co-extracted vanadium was scrubbed from the loaded organic solution at pH 11 using a solution containing 50 g/L Na2CO3. Over 90% of uranium was stripped from the loaded organic soluiton using an acidic solution containing 150 g/L ammonium sulphate in a single contact. It was also found that to obtain high uranium extraction, the chloride concentration should be controlled to less than 1 g/L in the aqueous phase.