摘要:
Provided are a method for producing sodium tungstate by supplying an oxidant (4) made of sodium nitrate or sodium nitrite to bring a tungsten containing material (3) and the oxidant (4) into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product (9); a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt (9) containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.
摘要:
Rare metals are recovered in high yields by contacting a strongly acidic solution containing at least one rare metal selected from the group consisting of gallium, uranium, molybdenum, rubidium, cesium, strontium, yttrium, niobium, tantalum, tungsten, ruthenium, osmium, rhodium, iridium, palladium, platinum, thallium and europium with a chelate resin having at least one phosphorus atom-containing functional group selected from phosphine group, phosphonium salt group, phosphinic acid group, phosphinic acid ester group, phosphonic acid group, phosphonic acid ester group and metal salts of these acids.
摘要:
A process is disclosed for separation and recovery of vanadium, molybdenum, iron, tungsten, cobalt and nickel from alumina-based materials, mattes, ores, manufacturing by-products and waste. These elements are oxidized. The oxides are reacted with gaseous HCI to form volatile chloride- bearing compounds that subsequently sublimate. The volatile compounds are condensed in a downward-stepped thermal gradient that allows collection of moderate to high purity compounds of individual elements with exception of a nickel-cobalt co-condensate. Nickel is separated from cobalt by precipitation of nickel chloride from concentrated HCI pressurized with gaseous HCI.
摘要:
Procédé d'extraction de tungstène et/ou de molybdène de solutions en mettant ces solutions en contact avec un oxyde de fer hydraté de surface spécifique élevée et qui peut être préparé en précipitant du nitrate ferrique ou un sel de fer analogue complètement dissocié avec de l'hydroxyde d'ammonium ou une autre base faible, en séchant et en broyant le précipité résultant pour obtenir un oxyde hydraté sous forme d'une poudre noire grossière, dans des conditions où le tungstène et/ou le molybdène sont absorbés sur l'oxyde hydraté de surfaces spécifiques élevées. Le procédé consiste à faire passer une solution contenant du tungstène et/ou du molybdène, par exemple une saumure (11) dans une colonne (10) contenant l'absorbant d'oxyde de fer hydraté et à extraire la saumure dépourvue de tungstène et/ou de molybdène par un orifice de sortie (12) au fond de la colonne. L'absorbant peut être régénéré en le mettant en contact avec une solution aqueuse possédant un pH supérieur à celui de la saumure dans la colonne.
摘要:
A method for reclaiming molybdate or tungstate from an aqueous solution, in which molybdate or tungstate from the aqueous solution is bound to a cationized inorganic carrier material which is insoluble in water at a pH value in the range between (2) and (6), the charged carrier material is separated, and the bound molybdate or tungstate is released back into aqueous solution at a pH value between (6) and (14). The cationized inorganic carrier material is, for example, a cationized layered silicate, preferably a bentonite which is ion-exchanged with a quaternary ammonium salt or a similar clay material. The method is suitable for reclaiming molybdate or tungstate during the delignification of cellulose using hydrogen peroxide, which is catalyzed using molybdate or tungstate. The reclaimed molybdate or tungstate can be returned into the delignification.