Columbite - tantalite decomposition

The purpose of the decomposition of raw materials is to convert tantalum and niobium compounds into a soluble form and prepare the solution for use in subsequent procedures. Fig. 116 presents the process flow chart. The most typical and frequently used raw materials are columbite-tantalite concentrates with the general formula (Fe, Mn)(Nb, Ta Cfo. 

Columbite - tantalite chlorination, 5-6 composition, 4 decomposition by H2S04, 6, 259-263 HF, 6,256-263... 

This approach explains the experimental fact that the complete decomposition of columbite or tantalite by sulfuric acid yields hydroxides of tantalum and niobium according to the first step of Equation (127). 

Another method of raw material decomposition is based on the fluorination of the raw material by the hydrofluoride method. No published data exists on hydrofluoride decomposition of columbite or tantalite concentrates. The interaction can, nevertheless, be discussed based on available information on the decomposition of lithium tantalate, LiTaC>3, and lithium niobate, LiNb03, using the hydrofluoride method [113,118,122]. 

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