A new method of chromate production by applying a new reaction system of KOH-KNO3-H2O (binary submolten salt system) is proposed and proved feasible. Under conditions of temperature 350 degrees C, KOH-to-chromite ore ratio 2:1, stirring speed 700 rpm, KNO3-to-chromite ore ratio 0.8:1, oxygen partial pressure 50%, and gas flow 1 L/min, chromium conversion ratio obtained is >98% with reaction time around 300 min. The decomposition of chromite ore in the system is a typical process of solid-liquid-gas reaction, which is coordinately controlled by mass diffusion in product layer and interface reaction. Apparent activation energy of decomposition in the temperature range from 280 to 370 degrees C is 55.63 kJ/mol. During reaction, oxygen dissolves into KOH-KNO3-H2O melt system first and some cluster, e.g. O-2(2-), is formed and the mass diffusion 2 coefficient of the cluster was calculated. The system can be considered as both a media of oxygen transportation and reactant donator. Potassium nitrate plays a role of catalyst in the oxidation decomposition reaction of chromite ore and potassium hydroxide. (C) 2009 American Institute of Chemical Engineers AIChE J, 55: 2646-2656, 2009

A New Method of Potassium Chromate Production from Chromite and KOH-KNO3-H2O Binary Submolten Salt System

Green metallurgical processing of chromite

Oxidative leaching of a Vietnamese chromite ore in highly concentrated potassium hydroxide aqueous solution at 300 °C and atmospheric pressure

The invention discloses a method for extracting vanadium and chromium from converter vanadium chromium slag. The method comprises the following steps: 1) adding Na2CO3 into the vanadium chromium slag, mixing uniformly and carrying out oxidizing roast on the mixture, wherein the addition of Na2CO3 is controlled according to a molar ratio of V2O3/Na2CO3 in the vanadium chromium slag being 0.1-0.4; grinding the roasted clinker, and leaching with water to obtain a primary roasted leaching solution and residue; 2) drying and grinding the residue to serve as a raw material from which vanadium and chromium can be extracted in the second step, adding Na2CO3 in the residue, mixing uniformly and carrying out oxidizing roast on the mixture, wherein the addition of Na2CO3 is controlled according to a molar ratio of (V2O3+Cr2O3)/Na2CO3 in the residue being 0.1-0.4; grinding the roasted clinker, and leaching with water to obtain a secondary roasted leaching solution; and 3) separately separating and extracting the vanadium and chromium from the primary roasted leaching solution and the secondary roasted leaching solution. The method disclosed by the invention is simple in process and high in vanadium and chromium immersion ratio and brings convenience for separating vanadium from chromium subsequently.

Method for extracting vanadium and chromium from converter vanadium chromium slag

A photoconductor containing an optional supporting substrate, a photogenerating layer, and at least one charge transport layer, and wherein the photogenerating layer contains a titanyl phthalocyanine prepared, for example, by dissolving a Type I titanyl phthalocyanine in a solution comprising a trihaloacetic acid and an alkylene halide; adding the mixture comprising the dissolved Type I titanyl phthalocyanine to a solution comprising an alcohol and an alkylene halide thereby precipitating a Type Y titanyl phthalocyanine; and treating the Type Y titanyl phthalocyanine with a monohalobenzene.

Titanyl phthalocyanine photoconductors

A method for the decomposition of chromium ore in a directly heated revolving tube is described, in which oxygen-containing gases are introduced into the revolving tube by means of below-bed nozzles.

Method for manufacturing alkali chromates from chromium ore

Process for recovering the vanadium present in the chromium ore chromite, as vanadium pentoxide, as a by-product from the vanadium-containing sodium chromate solution produced in the process of preparing sodium chromate and sodium dichromate from said ore, by precipitation of calcium vanadate from the sodium chromate solution, treatment of the precipitate with water and sodium carbonate, sodium bicarbonate, carbon dioxide or sodium carbonate and carbon dioxide, to precipitate calcium carbonate and electrolysis of the solution remaining after separation of the calcium carbonate precipitate, to produce vanadium pentoxide.

Process for the utilization of vanadium bound in chromium ore as vanadium(V) oxide by electrolysis

Process wherein the vanadium present in the chromium ore chromite is recovered as vanadium pentoxide during the course of the fusion of the chromium ore with alkali and its work-up to produce sodium chromate solution and sodium dichromate.

Process for the utilization of vanadium from chromium ore as vanadium (V) oxide

A process for recovering vanadium as ammonium metavanadate by: (a) precipitating calcium vanadate by adding a calcium compound to the chromate solution obtained from the ore; (b) treating the separated calcium vanadate with water and (i) sodium carbonate, (ii) sodium bicarbonate or (iii )CO Þ and NaOH to precipitate calcium carbonate (c) treating the solution remaining after removing the CaCO ý with an ammonium salt to form ammonium metavanadate (d) separating the vanadate precipitate from the remaining solution which is heated whilst at a pH of 10.5 or more to drive off ammonia and recycled to the production of the chromate solution.

Recovering vanadium from chromium ore

The invention relates to a novel process for preparing fluorosulfonic acid having low contents of low-boiling compounds in which hydrogen fluoride and sulfur trioxide are combined in stoichiometric amounts in a reaction vessel or by means of a reaction nozzle, the hot, gaseous fluorosulfonic acid that is formed is fed directly into a distillation column, and the fluorosulfonic acid is taken off at the bottom of the column or in the stripping section of the distillation column

Michael Batz

Papers

Method for manufacturing alkali chromates from chromium ore

Process for the utilization of vanadium bound in chromium ore as vanadium(V) oxide by electrolysis

Process for the utilization of vanadium from chromium ore as vanadium (V) oxide

Recovering vanadium from chromium ore

Process for preparing fluorosulfonic acid having low contents of low-boiling compounds