This report outlines the proposed processing route for the AZOD Zinc Oxide Project in Cusco, Peru, as defined in the 2011 preliminary economic assessment, incorporating pyrometallurgical and hydrometallurgical design criteria based on pilot, laboratory, and bench-scale testwork.
Report context
The AZOD Zinc Oxide Project is located in Cusco, Peru, and the processing concept described herein forms part of a NI 43-101 Technical Report on a Preliminary Economic Assessment (PEA) completed in October 2011. The process design criteria were developed for the recovery of zinc and lead from run-of-mine ore, with supporting data derived from pyrometallurgical pilot and laboratory tests, as well as bench-scale leach testwork on fume for the initial hydrometallurgical step. The report presents a simplified process flowsheet and major design criteria, but does not include full economic or operational details.
Processing route
Simplified flowsheet
The basis of the processing concept for the AZOD Project used in the AZOD PEA is shown in a simplified process flowsheet (Figure 17-1 in the original report). The flowsheet begins with run-of-mine (ROM) ore and includes both pyrometallurgical and hydrometallurgical stages. The figure is referenced but not reproduced here.
Pyrometallurgical stage
The pyrometallurgical stage is designed to treat the ore through crushing, fine ore storage, and a rotary kiln. Key design criteria include a daily ore throughput of 4,040 tonnes, with 332.5 operating days per year. The kiln is sized at 60 metres in length and 3.8 metres inner diameter, with an availability of 91%. Gas cooling and baghouse systems are included for fume capture. Anthracite ratios are specified at 2.7 and 3.0 kg per kg of zinc content for the Accha and Yanque ore types, respectively. The kiln operates at a temperature of 1,150°C, with no binder addition (reported as "No" for binder use). Residence times are 5 to 6 hours, depending on ore type. Fume production is targeted at 430 tonnes per day, with a blend quality of 69.6% for combined zinc and lead, and 82% for combined zinc oxide and lead oxide. Recovery of zinc and lead into the fume is reported as 92.4% and 97%, respectively. Slag production is estimated at 2,046 tonnes per day.
Hydrometallurgical stage
The hydrometallurgical stage is designed to process the fume product from the pyrometallurgical stage. Initial testwork included bench-scale leach tests on fume for the dehalogenation step, while downstream design criteria were assumed based on Metallicon and AMEC’s experience with conventional zinc refineries processing zinc sulphate solutions. Vendor recommendations were also considered. The stage includes dehalogenation, neutral leaching, acid leaching, cold and hot purification, and electrolysis. The refinery availability is set at 97%. The design includes a dehalogenation feed rate, pH control, and residence time; neutral leach with spent electrolyte flow and residence time; acid leach with defined feed rate and residence time; cold and hot purification stages with specified temperatures and residence times; and electrolysis with a defined number of cells, cathodic current density, and energy efficiency. The ratio of spent to pure solution, power consumption in cells, and slab zinc and residue lead production rates are also specified, though exact numerical values for many hydrometallurgical parameters are not fully listed in the available table.
Key reported parameters
| Parameter | Units | Value |
|---|---|---|
| Annual throughput – ore | t/a | 1,343,145 |
| Annual operating days | days | 332.5 |
| Daily throughput – ore | t/d | 4,040 |
| Crusher availability | % | 70 |
| Fine ore storage capacity | days | 1 |
| Size fine ore P100 | mm | 3 |
| Kiln size, length / inner diameter | m | 60 / 3.8 |
| Kiln availability | % | 91 |
| Gas cooling / baghouse lines | – | 2 |
| Anthracite ratio (Accha / Yanque) | kg anthracite / kg Zn content | 2.7 / 3.0 |
| Kiln temperature | °C | 1,150 |
| Binder | – | No |
| Residence time (Accha / Yanque) | h | 5 / 6 |
| Fume production | t/d | 430 |
| Fume quality (Zn+Pb) | % | 69.6 |
| Fume quality (ZnO+PbO) | % | 82 |
| Recovery in fume (Zn / Pb) | % | 92.4 / 97 |
| Slag production | t/d | 2,046 |
| Refinery availability | % | 97 |
| Overall zinc recovery | % | Not specified in available data |
Project website: https://finance.yahoo.com/news/zincore-announces-completion-filing-positive-012542040.html
*Note: Values for hydrometallurgical parameters such as feed rates, pH, residence times, temperatures, flowrates, cell quantities, current density, and power consumption are referenced in the original table but were not fully populated in the available extract.*
Technical qualifications
The process design criteria incorporate data from pyrometallurgical pilot and laboratory tests, as well as fume bench-scale leach tests for the initial hydrometallurgical step. However, downstream hydrometallurgical design criteria have been assumed based on Metallicon and AMEC’s experience with similar conventional zinc refineries, not on site-specific testwork. This introduces uncertainty in the applicability of these assumptions to the AZOD ore and fume characteristics. Vendor recommendations were also considered, but the report does not specify which equipment or suppliers were involved. The report notes that the PEA is preliminary in nature and does not include full economic analysis, and the flowsheet is simplified, meaning that detailed engineering and optimization have not been performed.
Source: AZOD Zinc Oxide Project, Cusco, Peru, NI 43-101 Technical Report on a Preliminary Economic Assessment, Project No. 167634, October 2011, Section 17.0 Recovery Methods.
