Tantalum powder production method and equipment; The method is carried out by reducing the alkali metal fluorine niobium and/or tantalate, in which the temperature of reduction reaction is 300-1050℃, the reducing agent is selected from alkali metal and at least one halide selected from Mg, Ca, Sr, Ba, Li, Ce reacts with the alkali metal fluorine niobium and/or tantalate to produce niobium and/or tantalate powder; When the niobium powder and tantalum powder are prepared according to the method of the invention, the reduction recovery rate is high. The niobium powder and tantalum powder are large in specific surface area, large in porosity and low in oxygen content. When the anode is made of capacitor, the niobium powder and tantalum powder have the characteristics of large porosity, low leakage current and high specific volume. The invention is convenient for industrial production.
In the existing technology, the tantalum powder prepared by reducing potassium flutantalate with alkali metals is widely used. The tantalum powder produced by this method is composed of aggregate particles composed of many primary particles. The tantalum powder particles have large porosity, which is especially suitable for electrolytic capacitors. This method can be improved in a variety of ways, for example: us patent 4,149,876 uses alkali metal halide as diluent, reduces K2TaF7 by stirring at 760℃ ~ 1000℃, controls the rate of sodium injection, and forces cooling the reactor to obtain tantalum powder.
Theoretically speaking, with the same method, the alkali metal can reduce potassium flonobate (K2NbF7) to make niobium powder. However, because when making potassium flonobate, it is often not easy to get pure potassium flonobate, but the mixture of potassium flonobate (K2NbOF5) and potassium flonobate containing niobium oxide. In addition, it is well known that tantalum oxide and niobium oxide cannot be reduced by alkali metals. Therefore, using alkali metals to reduce potassium fluomobate and/or potassium fluomobate containing niobium oxide cannot obtain pure niobium powder and/or tantalum powder, and will cause the loss of precious tantalum and niobium.
In addition, niobium powder may be contaminated when potassium fluorobate is reduced by alkali metals in reaction vessels and stirrers made of nickel-based alloys. Therefore, there is no successful industrial example of using alkali metals to produce capacitor grade niobium powder so far.
The invention relates to a method for preparing metallic niobium and/or tantalum powder by reducing the alkali metal fluorobium and/or tantalate containing oxides with alkali metals and at least one halide selected from Mg, Ca, Sr, Ba, Li and Ce, and simultaneously reducing the fluoride and oxides therein.
