Showing papers on "Vanadate published in 1968"

Production of vanadium trioxide

Abstract: 1,141,346. Vanadium trioxide. UNION CARBIDE CORP. 7 April, 1966, No. 15511/66. Heading C1A. V 2 O 3 is produced continuously from an ammonium vanadate compound by adding 0A13 lbs. gaseous ammonia per 1b. of vanadate, heating to 580-950‹ C. in water vapour and a reducing atmosphere produced at least partly by thermal decomposition of the vanadate for long enough to reduce the vanadate to V 2 O 3 , and cooling below about 180‹ C. before exposure to an oxygen containing atmosphere. The vanadates used are ammonium metavanadate, ammonium hexavanadate, ammonium vanadyl vanadate, ammonium decavanadate or mixtures of these; preferably ammonium metavanadate. The reducing atmosphere may be ammonia, hydrogen and water vapour, and a concurrent flow of solids and gases through at least the hot reaction zone improves the process. If ammonium metavanadate is used, it may be the sole starting material and no gaseous ammonia is added.

Method of producing vanadium compounds by alkaline leaching

Abstract: VANADIUM COMPOUNDS ARE PRODUCED FROM ORES BY ADDING SODIUM HYDROXIDE OF POTASSIUM HYDROXIDE TO FINELY GROUND RAW MATERIAL WHICH CONTAINS V2O3 OR ANOTHER INSOLUBLE FROM OF VANADIUM, THE CONCENTRATION OF THE SODIUM HYDROXDE OR POTASSIUM HYDROXIDE BEING IN THE RANGE OF 250 TO 400 G./L. NA2O OR K2O, WHEREIN THE REACTION MIXTURE IS HEATED TO A TEMPERATURE OF AT LEAST 250* AND OXYGEN OR COMPRESSED AIR ADDED TO OXIDIZE THE V2O3 TO V2O5, AND THEN FILTERING THE SOLUTION SO AS TO SEPARATE THE CRYSTALLINE ALKALINE VANADATE FORMED. IN ADDITION, PRIOR TO THE CRYSTALLIZATION SLUBLE FLUORIDES OR PHOSPHATES MAY BE ADDED TO THE SOLUTION SO AS TO FURTHER INCREASE THE CRYSTALLIZATION.

Phosphor and method of making

Abstract: IN A PROCESS FOR PREPARING A EUROPIUM ACTIVATED YTTRIUM PHOSPHATE VANADATE PHOSPOR, YTTRIUM OXIDE IS BLENDED WITH STOICHIOMETRIC AMOUNTS OF AN AMMONIUM PHOSPHATE COMPOUND AND A VANADIUM COMPOUND, EUROPIUM OXIDE IS THEN ADDED TO THE BLEND AND THE BLEND IS FIRED IN AIR AT A TEMPERATURE BETWEEN 1100*C. AND 1400*C. AFTER COOLING, THE BLEND IS PULIVERIZED TO A POWDER AND THE POWDER IS WASHED IN A DILUTE ACID.

Europium activated vanadate phosphors with tantalum and/or niobium additive

Abstract: EUROPIUM ACTIVATED YTTRIUM, GADOLINIUM AND YTTRIUMGADOLINIUM VANADATE PHOSPHORS ARE DOPED WITH TA, NB, OR EITHER TA, NB, OR TA-NB OPRIONALLY WITH SI, AND ARE USEFUL AS RED COLOR-EMITTING PHOSPHOR FOR HIGH-PRESSURE MERCURY LAMPS.