System and methods for providing nitric oxide can include at least one pair of electrodes configured to generate a product gas containing nitric oxide from a flow of a reactant gas, and at least one controller configured to regulate an amount of nitric oxide in the product gas generated by the at least one pair of electrodes using one or more parameters as an input to the controller. One or more sensors are configured to collect information relating to at least one of patient information, the reactant gas, the product gas, and an inspiratory gas into which at least a portion of the product gas flows, the sensors configured to communicate the information to the controller to be used as the one or more parameters. The patient information includes information relating to a methemoglobin (MetHg) measurement collected from a MetHg sensor.

System and methods for providing nitric oxide can include at least one pair of electrodes configured to generate a product gas containing nitric oxide from a flow of a reactant gas, and at least one controller configured to regulate an amount of nitric oxide in the product gas generated by the at least one pair of electrodes using one or more parameters as an input to the controller. One or more sensors are configured to collect information relating to at least one of patient information, the reactant gas, the product gas, and an inspiratory gas into which at least a portion of the product gas flows, the sensors configured to communicate the information to the controller to be used as the one or more parameters. The patient information includes information relating to a methemoglobin (MetHg) measurement collected from a MetHg sensor.

The present invention provides a high-concentration tin sulfonate aqueous solution, in which a divalent tin ion (Sn.sup.2+) concentration is 360 g/L to 420 g/L, a tetravalent tin ion (Sn.sup.4+) concentration is 10 g/L or less, a free methanesulfonic acid concentration is 40 g/L or less, a Hazen unit color number (APHA) is 240 or less, and a turbidity is 25 FTU or less. This aqueous solution is produced such that stannous oxide powder whose temperature is adjusted to a temperature of 10° C. or lower is added to an aqueous methanesulfonic acid solution having a concentration of 60% by mass to 90% by mass when the aqueous solution circulates in a state of being maintained at the temperature of 10° C. or lower, and the stannous oxide powder is dissolved.

The present invention provides a high-concentration tin sulfonate aqueous solution, in which a divalent tin ion (Sn.sup.2+) concentration is 360 g/L to 420 g/L, a tetravalent tin ion (Sn.sup.4+) concentration is 10 g/L or less, a free methanesulfonic acid concentration is 40 g/L or less, a Hazen unit color number (APHA) is 240 or less, and a turbidity is 25 FTU or less. This aqueous solution is produced such that stannous oxide powder whose temperature is adjusted to a temperature of 10° C. or lower is added to an aqueous methanesulfonic acid solution having a concentration of 60% by mass to 90% by mass when the aqueous solution circulates in a state of being maintained at the temperature of 10° C. or lower, and the stannous oxide powder is dissolved.

Methods and systems for dissolving an iron-containing ore are disclosed. For example, a method of processing and dissolving an iron-containing ore comprises: thermally reducing one or more non-magnetite iron oxide materials in the iron-containing ore to form magnetite in the presence of a reductant, thereby forming thermally-reduced ore; and dissolving at least a portion of the thermally-reduced ore using an acid to form an acidic iron-salt solution; wherein the acidic iron-salt solution comprises protons electrochemically generated in an electrochemical cell.

The present invention provides a high-concentration tin sulfonate aqueous solution, in which a divalent tin ion (Sn.sup.2+) concentration is 360 g/L to 420 g/L, a tetravalent tin ion (Sn.sup.4+) concentration is 10 g/L or less, a free methanesulfonic acid concentration is 40 g/L or less, a Hazen unit color number (APHA) is 240 or less, and a turbidity is 25 FTU or less. This aqueous solution is produced such that stannous oxide powder whose temperature is adjusted to a temperature of 10° C. or lower is added to an aqueous methanesulfonic acid solution having a concentration of 60% by mass to 90% by mass when the aqueous solution circulates in a state of being maintained at the temperature of 10° C. or lower, and the stannous oxide powder is dissolved.

The present invention provides a high-concentration tin sulfonate aqueous solution, in which a divalent tin ion (Sn.sup.2+) concentration is 360 g/L to 420 g/L, a tetravalent tin ion (Sn.sup.4+) concentration is 10 g/L or less, a free methanesulfonic acid concentration is 40 g/L or less, a Hazen unit color number (APHA) is 240 or less, and a turbidity is 25 FTU or less. This aqueous solution is produced such that stannous oxide powder whose temperature is adjusted to a temperature of 10° C. or lower is added to an aqueous methanesulfonic acid solution having a concentration of 60% by mass to 90% by mass when the aqueous solution circulates in a state of being maintained at the temperature of 10° C. or lower, and the stannous oxide powder is dissolved.

Disclosed herein are methods and systems that relate to oxidizing a metal ion of a metal oxyanion or a non-metal ion of a non-metal oxyanion from a lower oxidation state to a higher oxidation state at an anode and generate hydrogen gas at the cathode. The metal oxyanion with the metal ion in the higher oxidation state or the non-metal oxyanion with the non-metal ion in the higher oxidation state may be then subjected to a thermal reaction or a second electrochemical reaction, to form oxygen gas as well as to regenerate the metal oxyanion with the metal ion in the lower oxidation state or the non-metal oxyanion with the non-metal ion in the lower oxidation state, respectively.

A method for producing metallic silver by electro-deposition, including electrolyzing an electrolyte solution containing Ce(NO.sub.3).sub.3 in an anode zone and an electrolyte solution containing AgNO.sub.3 in a cathode zone by using an electrolytic cell with a specific diaphragm, wherein the electrolyte solution in the anode zone is not allowed to enter the cathode zone. After the electrolyzing is complete, the metallic silver with a high purity is obtained at the cathode, and a Ce.sup.4+-containing solution is obtained in the anode zone.

A method of recovering active materials from a rechargeable battery comprises placing an active material of a rechargeable battery in a cathode chamber comprising a cathode of an electrochemical cell comprising the cathode chamber, an anode chamber comprising an anode, and a membrane separating the cathode chamber from the anode chamber, contacting the active material in the cathode chamber with an electrolyte comprising an acid, ferric ions, and ferrous ions, and dissolving at least one of lithium and cobalt from the active material into the electrolyte. Related apparatuses for recovering metals from active materials of rechargeable batteries are also disclosed.