Abstract: There is disclosed a wet-processing method for combustion ashes of petroleum fuels, comprising a slurry preparation step of preparing a slurry of the combustion ashes; a metal oxidation step of preparing a slurry containing ammonium metavanadate; a solid/liquid separation step of removing solids from the slurry containing ammonium metavanadate; a double decomposition step for ammonium sulfate, of adding a magnesium compound to an aqueous ammonium sulfate solution recovered from the solid/liquid separation step; and an ammonia recovery step of recovering ammonia from a reaction solution recovered from the double decomposition step. The above metal oxidation step is conducted while controlling an ammonium sulfate concentration of the aqueous solution to 20 to 45% by weight and the temperature of the aqueous solution to not more than 50° C., and the above solid/liquid separation step is conducted using a specific solid/liquid separator while controlling the temperature of the slurry to not more than 40° C.

Abstract: A method is provided for treating ashes from the combustion of petroleum fuels by mixing the combustion ashes with water to produce a slurry; injecting either calcium oxide or calcium hydroxide into the slurry and reacting the calcium oxide or calcium hydroxide with the ammonium sulfate within the ashes to produce a slurry containing gypsum and ammonia; flowing the slurry containing gypsum and ammonia down from the top portion of packed column and air or steam up from the bottom portion of the packed column so that the air or steam strips the ammonia from the gypsum slurry; and separating the gypsum from the resulting ammonia-free slurry using a solid/liquid separator.

Abstract: The present invention relates to a liquid-circulating type redox flow battery which comprises(a) said battery being defined by a ratio (H/L) where (H) is the average height of each of said porous electrodes in a flow direction of each of said electrolytic solutions, and (L) is the length of each of said porous electrodes in a direction perpendicular to the flow direction of each of said electrolytic solutions, the ratio (H/L) being in the range of 0.18 to 1.95; and(b) said battery being defined by ratios (.SIGMA.s.sub.ai /S.sub.a) and (.SIGMA.s.sub.ci /S.sub.c) where (.SIGMA.s.sub.ai) is the sum of the cross-sectional area of an inlet for introducing said positive electrolytic solution into said positive cell, (.SIGMA.s.sub.ci) is the sum of the cross-sectional area of an inlet for introducing said negative electrolytic solution into said negative cell, (S.sub.

Abstract: The present invention provides a liquid-circulating battery including a positive electrode, a negative electrode, a permeable membrane interposed between the positive and negative electrodes to hold the same in separated relation to each other and to partition the same into a positive chamber and a negative chamber, two porous liquid-permeable carbon electrodes disposed respectively in the positive and negative electrolytic solutions being circulated respectively into the positive and negative chambers such that an oxidation-reduction reaction occurs and causes charging and discharging, wherein the permeable membrane is an ion-exchange me membrane including as an ion exchanger layer a polymeric pellicle which results from crosslinking of a halogenated alkylated product of an aromatic polysulfone type polymer with use of a polyamine and which has an ion exchange capacity of 0.3 to 8.0 milliequivalent/gram of dry resin and a thickness 0.1 to 120 .mu.

Abstract: The present invention provides a redox battery using two layer, liquid permeable, porous electrodes, each having a porous electrode layer having high surface area comprising carbon fiber at the septum side and a porous electrode layer having low surface area comprising carbon fiber at the bipolar plate side. The battery has excellent properties such as high current density, low pump pressure loss, and high output.

Abstract: A method for producing an electrolytic solution containing vanadium as positive and negative electrode active material, the electrolytic solutions being suitable for a redox battery which comprises: the steps of (1) a vanadium compound is dissolved in a solvent under an alkaline or neutral condition, a polyvanadate compound is precipitated and isolated by thermal polymerization of vanadium ions under an acidic condition; (2) a part of the polyvanadate compound is baked in an inert or oxidizing gas atmosphere so as to remove ammonium ions; (3) a trivalent vanadium compound is formed by treating another part of the polyvanadate compound under a reductive atmosphere; (4) a trivalent vanadium electrolytic solution is formed by dissolving the trivalent vanadium compound in an acid solution; and (5) vanadium pentoxide and a part of the trivalent vanadium compound are reacted by mixing so that mixed electrolytic solutions of V.sup.4+ and V.sup.3+ are formed.

Abstract: Tri- and tetravalent vanadium solutions suitable for a redox battery are produced as follows. Vanadium pentaoxide or ammonium vanadium is reduced in the presence of a concentrated sulfuric acid and a reducer, thus producing a solution containing tetravalent vanadium. At least a portion of the trivalent vanadium solution is heated to 180.degree.-250.degree. C., thus producing a trivalent vanadium compound. If the trivalent compound produced is a solid, it is collected and solubilized in water and/or sulfuric acid. Then, unreacted sulfur is filtered out, thus obtaining a trivalent vanadium solution.

Abstract: In a redox battery including an electrolytic cell which has a circulating type electrolytic solution and an intermittent circulating type electrolytic solution which has a membrane and which employs an electrolytic solution permeable porous electrode, a solution of vanadium (II/III) dissolved in sulfuric acid is used as an active material on the negative electrode of a redox couple, and an oxidizing substance in a gas (such as oxygen) or in electrolytic solution is used as an active material on the positive electrode of the redox couple. The redox battery of the invention shows high energy density, and has a small size and a high output, thus it can be used for an electric vehicle or as a portable battery.

Abstract: A vanadium electrolytic solution containing highly concentrated and dissolved vanadium is produced by a method wherein a vanadium compound selected from the group consisting of ammonium metavanadate and vanadium pentaoxide is subjected to a reduction operation in the presence of inorganic acids. At this time, by repeating the addition of the concentrated inorganic acids and the vanadium compound, a tetravalent and pentavalent vanadium solution of 3.4 mol/l is obtained.In addition, the resulting vanadium electrolytic solution is electrolyzed, whereby tetravalent vanadium is reduced to be trivalent on the negative electrode and is oxidized into pentavalent vanadium on the positive electrode, and then pentavalent vanadium is reduced into tetravalent vanadium by a reducing agent to form a discharged couple of trivalent and tetravalent vanadium, and an electrolytic solution is obtained which is capable of being charge-discharged.