摘要:
Disclosed herein is a method for producing potassium fluoroniobate crystals by which highly pure, large-sized potassium fluoroniobate crystals can be obtained in high yield and which is advantageous from the viewpoints of material cost and material-dissolving operation; and potassium fluoroniobate crystals. This production method comprises the first and second steps (a) and (b) of (a) adding a potassium-containing electrolyte to a starting material comprising niobium to precipitate potassium oxyfluoroniobate and/or fluoroniobate as coarse crystals, and separating the coarse crystals by filtration, and (b) dissolving the coarse crystals in a recrystallization solvent that is an aqueous solution comprising 12 to 35% by weight of hydrofluoric acid and that has been heated to a temperature of 50° C. or more, and cooling the solution to 40° C. or lower at a cooling rate of less than 20° C./h to precipitate potassium fluoroniobate as crystals.
摘要:
The object of the present invention is to provide a method of producing low oxygen-containing potassium fluorotantalate crystals or low oxygen-containing potassium fluoroniobate crystals, the crystals obtained by the production method, and a method of analyzing oxygen contained in these crystals.The method of producing low oxygen-containing potassium fluorotantalate crystals comprises generating recrystallized potassium fluorotantalate crystals by controlled cooling of a saturated solution of potassium fluorotantalate containing hydrofluoric acid as an essential component, collecting the generated recrystallized crystals through filtration, and drying the collected recrystallized crystals in a drying apparatus so as to obtain the crystals, and the production method is characterized in that the saturated solution of potassium fluorotantalate containing hydrofluoric acid as an essential component contains hydrofluoric acid in a concentration of 0.5 mol/l to 10 mol/l.
摘要:
In a window of an office of a banking facility, there is disposed a composite apparatus in which a window machine facing the teller is united with an automatic cash handling machine facing the lobby and which is integrally configured in a window counter. During the office hours of the window, the window machine of the composite apparatus is employed by the teller for banking services. In a period of time beyond the office hours, a shutter for prevention of crimes is moved downward onto the window counter, which enables the users to externally access the automatic cash handling machine.