Abstract: A process for producing a complex oxide containing the valuable metal and an alkali (earth) metal salt, which comprising co-milling a mixture of the valuable metal oxide and/or a precursor thereof, or a mixture of a substance containing the valuable metal oxide and/or a precursor thereof, with an alkali (earth) metal salt to a particle size of the valuable metal oxide or a substance containing the oxide, of 10 ?m or less, and heating the co-milled product to a temperature of at least 200° C. so as to induce a solid-phase reaction of the valuable metal oxide with an alkali (earth) metal salt.

Abstract: A method for recovering high purity nickel, cobalt, molybdenum and vanadium from a waste catalyst in high yield by convenient means is provided. The method includes a step of heating a waste catalyst containing valuable metals in a non-oxidizing atmosphere, thereby deoiling an adhered oil content by thermal decomposition, a step of co-milling the deoiled waste catalyst and a chloride to form a chloride of nickel and/or cobalt, a step of water-leaching the co-milled waste catalyst to dissolve nickel and/or cobalt in water, a step of oxidizing leaching residue containing molybdenum and/or vanadium after water leaching to form an oxide of molybdenum and/or vanadium; and a step of subjecting the leaching residue containing the oxide of molybdenum and/or vanadium to alkali leaching to dissolve the molybdenum and/or vanadium in an alkali solution.

Abstract: To simultaneously overcome a drawback in that proceeding of a solid phase carbonization reaction requires high temperature and a drawback in that the reaction requires use of expensive materials. A method for producing a carbide of a Group IVA, VA, or VIA transition metal in the periodic table and/or a composite carbide of the transition metal and iron, the method including the step of co-milling a ferroalloy containing a Group IVA, VA, or VIA transition metal in the periodic table and incidental impurities and a carbon material mainly composed of carbon in a vacuum or an atmosphere of an inert gas to effect a solid phase reaction between the ferroalloy and the carbon material.

Abstract: A process for producing a complex oxide containing the valuable metal and an alkali (earth) metal salt, which comprising co-milling a mixture of the valuable metal oxide and/or a precursor thereof, or a mixture of a substance containing the valuable metal oxide and/or a precursor thereof, with an alkali (earth) metal salt to a particle size of the valuable metal oxide or a substance containing the oxide, of 10 ?m or less, and heating the co-milled product to a temperature of at least 200° C. so as to induce a solid-phase reaction of the valuable metal oxide with an alkali (earth) metal salt. The process improves the solid-phase reaction rate and the selectivity of the value metal complex oxide, which results in the enhancement of the productivity for the complex oxide.

Abstract: The pressure in the coking chamber of a coke oven is held at about atmospheric pressure, and the temperatures at the opposite longitudinal ends of the combustion chamber are independently controlled. Fuel gas is supplied to hold the temperature at the opposite longitudinal ends to be at least about 1000.degree. C. separately from a main burner for the combustion chamber, and the pressure in the coking chamber during the first part of coking is kept in a range from 5 mmH.sub.2 O below atmospheric to 10 mmH.sub.2 O above atmospheric pressure. This allows efficient coke production even with low moisture content coking coal, and coal crumbling near the oven doors is not a problem. The process is typically carried out in a coke oven having a pressure control system for each coking chamber including plural piping devices for supplying a pressure fluid and switching valves for selectively applying the pressure fluid to the nozzle in the rising pipe through any selected one of the piping systems.