How to Select Low-Grade Tantalum-Niobium Ores?

How to Select Low-Grade Tantalum-Niobium Ores? Extraction Methods for Tantalum-Niobium Ores Using Gravity Separation Equipment

How to select low-grade tantalum-niobium ores? The extraction method for tantalum-niobium ores using gravity separation equipment generally involves discarding most of the gangue minerals during gravity separation to obtain a low-grade mixed tantalum-niobium concentrate. The concentrate entering the cleaning process has a complex mineral composition, generally containing multiple useful minerals, making separation difficult. Multiple beneficiation methods are typically used, such as gravity separation, flotation, electromagnetic separation, or combined beneficiation and metallurgical processes, to achieve the separation of multiple useful minerals.

Tantalum-niobium ores have complex mineral compositions and are difficult to separate. How to select low-grade tantalum-niobium ores? It often requires one or two or more methods, such as magnetic separation, gravity separation, flotation-gravity separation, flotation, electrostatic separation, and chemical treatment, to obtain a concentrate. In practice, gravity separation is the most common method for tantalum-niobium beneficiation. Stage grinding and stage separation are the main processes in tantalum-niobium ore gravity separation.

Tantalum-niobium ores are broadly divided into two types: one is placer deposits with high clay content and strong viscosity; the other is rock deposits with very low original ore grade. The extraction methods and equipment for these two types of low-grade tantalum and niobium ore differ significantly and need to be described separately.

1. Extraction Methods for Low-Grade Tantalum and Niobium Placer Deposits

For the beneficiation of tantalum and niobium placer deposits with high mud content and strong viscosity, washing is essential. Large-scale cylindrical washing machines are commonly used for washing tantalum and niobium placer deposits. After washing, the mud in the tantalum and niobium ore is removed. Since the tantalum and niobium ore and waste rock in these placer deposits have a high degree of individual liberation, gravity separation can be used to discard a large amount of waste rock and obtain a gravity concentrate. The gravity separation equipment used is mostly a jig.

After gravity separation, tantalum-niobium ore still requires further beneficiation and purification. Purification can be achieved through gravity separation, flotation, electrostatic separation, or a combination of these processes, depending on the specific circumstances. For example, the Greenbus mine directly uses jigs for roughing of -10mm tantalum-niobium ore, while a Canadian tantalum mine has developed a combined gravity-flotation-gravity separation process. In this process, gravity separation is the primary method, with flotation used only to process fine slime. In short, gravity separation and its equipment play a crucial role in the beneficiation of tantalum-niobium ore.

2. Extraction Methods for Low-Grade Tantalum-Niobium Ore

my country's raw tantalum-niobium ore is generally low-grade, brittle, and dense. To ensure proper grinding particle size and avoid over-grinding, primary grinding often employs a closed-circuit system of rod mills and linear screens to minimize over-grinding. Secondary grinding uses a closed-circuit system of ball mills and high-frequency vibrating screens. This not only strictly controls particle size but also increases processing capacity and grinding efficiency. A single gravity separation process is used, with equipment such as spiral sluices and shaking tables primarily employed.

The rough concentrate obtained from the roughing process is generally a mixed concentrate, requiring further refining to separate various useful minerals. Refining of tantalum-niobium ore can be achieved using processes such as high-intensity magnetic separation, flotation, and electrostatic separation, depending on the specific properties of the ore.

The density of tantalum-niobium minerals is typically above 5500 kg/m³, while the density of gangue minerals is generally around 2700 kg/m³. The ease of separation by specific gravity (e-value) is greater than 2.5, making gravity separation of tantalum-niobium ore relatively easy. Gravity separation is the preferred method for determining tantalum-niobium beneficiation methods.