A metal titanium production apparatus includes: a reductor that subjects titanium tetrachloride to a reduction process in presence of bismuth and magnesium to obtain a liquid alloy containing titanium and the bismuth; a segregator that subjects the liquid alloy to a segregation process to obtain a precipitate; and a distillator that subjects the precipitate to a distillation process to obtain metal titanium, and the distillator sets an atmosphere so as to preferentially vaporize the bismuth attached to the precipitate and then sets the atmosphere so as to vaporize the bismuth forming the precipitate.

Provided is a method for preparing a reduced titanium powder by a multistage deep reduction, including the following steps of: uniformly mixing a dried titanium dioxide powder with a magnesium powder to obtain a mixture, adding the mixture in a self-propagating reaction furnace, triggering a self-propagating reaction, obtaining an intermediate product of which low-valence titanium oxides Ti.sub.xO are dispersed in an MgO matrix, leaching the intermediate product with a hydrochloric acid as a leaching solution, performing filtering, washing and vacuum drying to obtain a low-valence titanium oxide Ti.sub.xO precursor, uniformly mixing the low-valence titanium oxide Ti.sub.xO precursor with a calcium powder, performing a pressing to obtain semi-finished products, placing the semi-finished products in a vacuum reduction furnace for a second-time deep reduction, and leaching a deep reduction product with a hydrochloric acid as a leaching solution so as to obtain the reduced titanium powder.

A cold crucible structure according to an embodiment of the present invention includes a cold crucible structure according to an embodiment of the present invention includes: a cold crucible unit including hollow top and bottom caps, a plurality of segments connecting the top cap and the bottom cap, slits disposed between the segments, and a reaction area surrounded by the segments; and an induction coil unit disposed to cover the outer side of the cold crucible unit and disposed across the longitudinal directions of the segments and the slits, in which the diameter of the reaction area is defined as a crucible diameter, the crucible diameter is 100 to 300 mm, and a width of each of the slits is defined by $d_{\mathrm{slit}}\le 0.3\times \frac{\varnothing }{50}$
(mm)(where d.sub.slit is the width of each of the slits and Ø is the crucible diameter).

A method for extracting metal values from a low grade primary metal oxide ore feedstock is provided. The method includes providing a low grade primary metal oxide ore containing a primary metal and scandium; subjecting the ore to acid leaching, thus yielding an acidic leachate; extracting the primary metal and scandium from the leachate, thereby yielding an acidic barren leachate; and using the acidic barren leachate in a subsequent iteration of the acid leaching step.

The present invention provides a method for selective recovery of a valuable metal from a waste denitrification catalyst through alkali fusion, the method comprising the steps of: (a) adding an alkali metal to a waste denitrification catalyst, followed by mixing and alkali fusion, to generate a calcination product; (b) subjecting the calcination product to water-leaching to recover an alkali leachate and a residue; (c) adding a precipitator to the alkali leachate, followed by stirring, to recover calcium metavanadate (Ca(VO.sub.3).sub.2) or calcium tungstate (CaWO.sub.4) through precipitation; and (d) subjecting the recovered calcium tungstate to acid decomposition to prepare tungstic acid. Therefore, vanadium and tungsten can be recovered at high efficiency by a method in which a precipitator is added to a leachate, which is obtained by adding an excess amount of an alkali metal to a waste denitrification catalyst and carrying out calcination and water-leaching, and then a reaction rate is controlled.

Provided is sponge titanium produced by the Kroll method, in which the total of a chlorine content and a magnesium content is 350 ppm by mass or lower, and a filling density is 1.65 g/cm.sup.3 to 1.95 g/cm.sup.3. The present invention can provide sponge titanium for large ingot production that is difficult to cause problems due to chloride inclusion at the time of melting production of the large ingot by a melting method not associated with compression molding and has easy component control and also provide a method for industrially efficiently producing the sponge titanium.

Provided is sponge titanium produced by the Kroll method, in which the total of a chlorine content and a magnesium content is 350 ppm by mass or lower, and a filling density is 1.65 g/cm.sup.3 to 1.95 g/cm.sup.3. The present invention can provide sponge titanium for large ingot production that is difficult to cause problems due to chloride inclusion at the time of melting production of the large ingot by a melting method not associated with compression molding and has easy component control and also provide a method for industrially efficiently producing the sponge titanium.

A method of producing titanium cobbles includes: a preparation step of preparing a scrap material containing 50% by mass or more of metal titanium; a first crushing step of roughly crushing the scrap material using a first crusher; a second crushing step of crushing the scrap material, which has been roughly crushed in the first crushing step, using a second crusher; a dust collection step of collecting fine dust of the scrap material generated in the second crushing step; and a first classification step of classifying products obtained by crushing the scrap material, which have been generated in the second crushing step, into medium particles with particle sizes within a predetermined particle size range, large particles with particle sizes larger than the particle size range, and small particles with particle sizes smaller than the particle size range.

The invention is a microwave gun and arc plasma torch furnace used to refine titanium, Ti, from titanium dioxide, TiO.sub.2, powder. The furnace includes high frequency microwave emitters that create a high temperature zone strongly vibrating the titanium dioxide powder, TiO.sub.2, and lengthening and weakening the valence bonds in the titanium dioxide powder, TiO.sub.2, titanium, Ti, and oxygen, O, atoms. The furnace also uses nitrogen arc plasma torch generators to generate a N.sup.+ plasma to completely disassociate the titanium, Ti, and oxygen, O, atoms into titanium ions, Ti.sup.+ and oxygen ions, O.sup., and permitting the formation of nitrogen dioxide, NO.sub.2, and melted titanium, Ti.

The invention relates to a method for starting up a fluidized bed boiler, such as a circulating fluidized bed (CFB) or a bubbling fluidized bed (BFB) boiler, for operation with a predetermined concentration of ilmenite particles in the bed material. The invention also relates to a method for pre-oxidizing ilmenite, to pre-oxidized ilmenite and to the use of pre-oxidized ilmenite in a fluidized bed boiler.