METHOD OF PROCESSING QUARTZ LEUCOXENE CONCENTRATE Russian patent published in 2005 - IPC

FIELD: metallurgy of rare-earth metals; methods of processing quartz leucoxene concentrates containing high concentrations of secondary rutile quartz aggregates; production of artificial rutile.

SUBSTANCE: proposed method includes leaching-out concentrate at size of 0.02 mm by solution of hydrofluoric acid at concentration of 7.5-8.0% and solid-to-liquid ratio=1 : (0.91); cake is subjected to washing, repulping and washing-off sludge followed by separating quartz and leucoxene for obtaining artificial rutile performed by floatation in alkaline medium at conversion of quartz into foam product and concentration of leucoxene in chamber product. Chamber product is subjected to test floatation in alkaline medium performed at three stages: at two first stages quartz changes to foam product and at third stage of test floatation, titanium dioxide at content of main substance of 90-91% changes to chamber product and enriched quartz leucoxene concentrate at content of titanium dioxide of 70-71% changes to foam product. Main and test floatation processes are performed with the use of diacetate alkyl propylene diamine at radical C₁₆-C₁₈ as floatation reagent. After leaching-out the initial concentrate, solution containing hydrofluosilicic acid and fluorides of metals is evaporated at stripping and condensation of hydrofluosilicic acid. Silicon dioxide is precipitated from condensate; after separation of sediment, sodium fluoride is introduced into filtrate and it is evaporated for obtaining complex sodium salt of hydrofluosilicic acid which is calcined at temperature of 300-310°C for obtaining hydrogen fluoride and sodium fluoride in gas phase. Hydrogen fluoride is condensed and is directed for leaching-out new portion of concentrate and sediment of sodium fluoride is directed for precipitation of new portion of complex sodium salt of hydrofluosilicic acid for subsequent regeneration.

EFFECT: low cost of artificial rutile due to simplified technology; possibility of performing closed reagent regeneration cycle.

2 cl, 1 ex