Tantalum niobium deposits are mainly tantalum iron and burnt greenstone. Tantalum niobium iron ore contains a lot of tantalum is called tantalite, niobium iron ore contains a lot of niobium.
Tantalum niobite and pyrite can be collected by cationic collector or anion collector. It is better to use complexing collector (such as sodium hydroxamic acid) for flotation.
With oleic acid as the collector, tantalum niobium ore has the best planktonic property at pH value of 6-8, tantalite and niobite are inhibited in acidic medium, while quartz, feldspar and dolomite have poor planktonic property at any pH value. Therefore, when pH=6~8, oleic acid is used as the collector to separate tantalum ingots from quartz and other vein rocks.
When tantalum niobium is treated with 10% acid (sulfuric acid), it becomes simply suspended. As the amount of acid increases, the floatability of tantalum niobium ore increases. With 1% treatment, the degree of activation is similar to sulfuric acid. When oleic acid is used as a collector at a concentration of 10-20 mg/l, tantalum ingots and some vein rocks can be controlled. When cationic collector is used, some mineral deposits such as tantalum and niobium ore are activated, but the recovery of tantalum and niobium ore decreases with the addition of its dosage. When oleic acid is used to harvest tantalum niobium, a small amount of sodium can keep all deposits in check.
According to the ratio of niobium and tantalum content in the extraction process, two extraction methods were used: separation extraction and reverse extraction. When the content difference between niobium and tantalum is large, the separation extraction method is mostly used. Figure 1 shows the curve of extracting niobium and tantalum by MIBK. As can be seen from the figure, niobium was firstly extracted under low acidity, and tantalum was extracted under high acidity. The co-extraction method is to extract niobium tantalum into the organic phase together, and then separate and back-extract niobium and tantalum from the supported organic phase of niobium tantalum, i.e. high-acidity back-extraction of niobium and low-acidity back-extraction of tantalum. The extraction method is simple and easy to operate, which is widely used in niobium and tantalum plants in the world. When niobium tantalum is extracted into organic phase, it becomes the key step to separate niobium tantalum from organic phase by washing and backextraction. Suitable scrubbing agents and reverse extractant should be selected according to the selected extractant and aqueous phase liquid. For example, in the sec-octanol-hf-h2so4 extraction system, the supported organic phase is usually washed with sulfuric acid solution, and H2SO41mol/L is used.
