Beneficiamento de minérios pláceres por concentração gravítica – uma abortagem ao uso de técnicas sustentáveis

Abstract

Mining in Mozambique plays a significant role in the country's economy, contributing to revenue generation, employment, and economic development. However, it is crucial to ensure that this activity is conducted responsibly, respecting environmental and social aspects, and that the benefits are shared equitably with local communities. To address this issue, it is essential to adopt responsible practices and employ cleaner and safer technologies. This work focuses on the beneficiation of placer ores from the Niassa province using the Wilfley table as the primary tool. The study assessed the table's effectiveness in separating gold (including other heavy minerals) from low-density minerals (gangue). The process efficiency was monitored through analyses of the produced concentrates and tailings, based on variations in three table parameters: particle size (−500 + 250 and −1000 + 500μm ); table tilt angle (2° and 6°), and water flow rate ( 0.126 and0.132 L/s). Concentration results were compared in terms of the recovery of the target mineral, and higher recoveries were obtained in both particle size ranges at an angle of 6° and a flow rate of0.126 L/s. The research results indicated a need for improvement in the gold's mineralogical conditions, as metallurgical recovery levels were low compared to other metals of the same nature. This led to the conclusion that the gold's liberation degree was low, thereby affecting the recovery performance.