There are mainly three decomposition methods for tantalum concentrate in industry: alkali melting method, acid decomposition method and chlorination decomposition method. In the process of producing compounds from tantalum concentrate, the separation of tantalum and niobium from each other and the separation of tantalum, niobium from impurities are among the most difficult tasks. The main methods for separating and extracting tantalum and niobium are: liquid-liquid extraction method; Step crystallization method of fluoxite Ion exchange method Select the reduction method; Chloride distillation method. The above-mentioned methods each have their own technological characteristics, but those with industrial significance are: liquid-liquid extraction method, partial crystallization method and chloride distillation method. Liquid-liquid extraction is currently the most important process method for the extraction and separation of tantalum and niobium due to its advantages such as large extraction capacity, high product purity and continuous production process.
Tantalum has excellent plasticity and is extremely easy to undergo plastic processing. Various industrial profiles (tubes, bars, wires, strips) can be produced by conventional processing techniques (extrusion, forging, rolling and drawing). Tantalum and tantalum alloy ingots all have coarse grain structures. They must first be extruded or hot forged to break the grains (initial processing) before they can be further processed into materials. Pure tantalum can be forged and opened at room temperature. The opening temperature of tantalum alloy is generally 1100 to 1200 ℃. During the processing, the surface of tantalum alloy oxidizes to form loose oxides, which can penetrate into the alloy matrix and form a hard permeable layer, causing cracks during processing. Therefore, throughout the entire processing, efforts should be made to protect the metal surface from oxidation. At present, the protection methods for tantalum billets include salt bath heating, coating, cladding, and inert gas protection, etc. The extrusion method can produce metal tubes, rods and profiles of different specifications. The ingots of tantalum can be directly forged into rolled slabs. Glass coating can be used as a lubricant; The rolling of tantalum alloy sheets usually employs two-high or four-high rolling mills, with a pass deformation of 10% to 15%. When rolling 2.5mm thin plates, the total shape is 70% to 80%. When rolling 2.5mm thin plates, kerosene or palm oil is used as the lubricant.
