Project Overview
Location: Salta Province, Argentina
Process Type: Atmospheric or HPAL Leaching (under evaluation)
Annual Production: 1.75 million tonnes (5,000 tpd)
Feed Grade: 0.2144% Cs
Recovery Rate: Not specified
Final Product: 80% Cesium Formate Brine
Project Stage: PEA Trade-off Study
Detailed Process Description
Processing Options
The project is evaluating two main processing routes: atmospheric leaching and High-Pressure Acid Leaching (HPAL). The HPAL option presents higher capital costs but offers advantages in reduced acid and limestone consumption, potentially leading to lower operating costs. The facility is designed to process 1.75 million tonnes annually over a 14-year mine life.
Atmospheric Leaching Circuit
The atmospheric leaching process begins with ROM ore feeding to a rotary breaker for size reduction. Material undergoes ball milling in closed circuit with hydrocyclones to achieve a P80 of 44 microns at 30% solids density. The slurry feeds two atmospheric agitated leach tanks with a 1.5-hour residence time, using sulfuric acid addition at 400kg/t for cesium extraction. Post-leaching, the slurry undergoes thickening and filtration, with solids reporting to a dry stack facility.
HPAL Alternative
The HPAL option maintains similar front-end processing but replaces atmospheric leach tanks with two parallel autoclave circuits operating at high temperature and pressure. This redundancy in autoclave systems provides operational flexibility and maintenance advantages. The process aims to optimize acid consumption while maintaining high cesium recovery rates.
Downstream Processing
Both process options share a common downstream circuit where aluminum sulfate is added to the leach solution before cooling to promote cesium alum formation. The process includes multiple dissolution and crystallization steps, followed by treatment with barium hydroxide to remove impurities. The final product is cesium hydroxide, which is converted to cesium formate using formic acid to produce an 80% cesium formate brine for market sale.
