Abstract: A method for producing high-purity manganese sulfate monohydrate from a low-grade composition includes acquiring a primary leached manganese solution by adding sulfuric acid and a reductant to a low-grade manganese-containing composition and leaching manganese therefrom; acquiring a secondary leached manganese solution from which primary impurities have been eliminated by adding calcium hydroxide to the primary leached manganese solution; acquiring a tertiary leached manganese solution from which secondary impurities have been eliminated by adding sulfides to the secondary leached manganese solution; acquiring manganese oxide from precipitating manganese by using sodium hydroxide in the tertiary leached manganese solution so as to control the pH thereof; adding sulfuric acid to the manganese oxide and redissolving; and drying the redissolved manganese oxide and acquiring high-purity manganese sulfate monohydrate.

Abstract: A device for removing ammonia from a gas stream has a plurality of conduits that divide the gas steam into a plurality of separate gas streams. Spray nozzles located in each of said conduits spray a dilute acid solution into the streams. The acid solution is aqueous sulfuric acid and ammonium sulfate is produced. The conduits are substantially unobstructed enabling the device to create less than 10 Pa back pressure to the gas stream.

Abstract: An apparatus for evaporating waste water and reducing gas emissions includes an evaporator device (7, 31) configured to receiving a portion of flue gas emitted from a boiler unit (1) and waste water to directly contact the flue gas with the waste water to cool and humidify the flue gas and to dry solid particulates within the waste water. In some embodiments, the waste water may be a component of a mixture formed by a mixer device (25) prior to being contacted with the flue gas to humidify and cool the flue gas and dry solids within the waste water. An alkaline reagent as well as activated carbon can be mixed with the waste water prior to the waste water contacting the flue gas. Solid particulates that are dried within the cooled and humidified flue gas can be separated from the flue gas via a particulate collector (9).

Abstract: A system including a reductant source storing reductant, an ammonia generation system configured to generate gaseous ammonia via cavitation, and a gaseous ammonia delivery device in fluid communication with the ammonia generation system and an exhaust system. The system may selectively activate the ammonia generation system responsive to a detected temperature of an exhaust gas of an exhaust system being equal to or below a predetermined value. The ammonia generation system may utilize ultrasonic cavitation or laser cavitation to generate gaseous ammonia to be delivered to the exhaust system responsive to the temperature of the exhaust gas of the exhaust system being equal to or below the predetermined value. If the temperature of the exhaust gas of the exhaust system above the predetermined value, a dosing module to dose reductant to the exhaust system may be activated.

Abstract: The present disclosure is directed to the use of elemental or speciated iodine and bromine to control total mercury emissions.

Abstract: A one-pot approach for preparing ArSH capped Cu2ZnSnS4, Cu2ZnSn(S(1-x)Sex)4, Cu2SnS3, CuInS2, and CuIn(S(1-x)Sex)2 nanocrystals is provided. Examples involving reacting copper (II) acetylacetonate and indium chloride with thiourea and 2-mercapto-5-n-propylpyrimidine in the presence of an organic solvent are described. Monodispersed CuInS2, nanocrystals having a size of about 100 nm were prepared. Examples involving reacting copper (II) acetylacetonate, zinc chloride, and tin chloride with thiourea and 2-mercapto-5-n-propylpyrimidine in the presence of an organic solvent are described. Monodispersed Cu2ZnSnS4 nanocrystals having a size of about 2 nm were prepared. Nanociystals obtained were found to have excellent crystallinity, stoichiometry, and high collective photovoltaic activity without the need for postprocessing such as high temperature annihilation in a sulfur atmosphere.

Abstract: The invention relates to the use of at least one compound of formula (1): R—Sn—R???(1) wherein R and R? are each a hydrocarbon radical containing between 1 and 12 carbon atoms and n is a whole number between 1 and 8, for maintaining the viscosity of liquid sulfur at a value lower than 60,000 mPa·s, preferably lower than 30,000 mPa·s, especially preferably lower than 10,000 mPa·s. The invention also relates to a method for preparing low-viscosity liquid sulfur and to liquid sulfur compositions comprising at least one compound of formula (1).

Abstract: An exhaust gas aftertreatment system and a method of use reduces the amount of N2O produced in at least one of: (1) a selective catalytic reduction (SCR) catalytic converter and (2) an ammonia slip catalyst (ASC) in the exhaust gases from a combustion engine. The system includes an SCR catalytic converter arranged in an exhaust gas line upstream of an optional ASC. The exhaust gases pass through the SCR catalytic converter and any ASC before they are released by the exhaust gas outlet. An injector injects a reducing agent into the exhaust gases in the exhaust gas line upstream of the SCR catalytic converter at a dosing frequency F. A control unit generates a control signal to adjust the dosing frequency F so that the amount of N2O produced in at least one of: (1) the SCR catalytic converter and (2) the ASC is minimized while maintaining the amount of reducing agent added.

Abstract: One aspect of the invention relates to a method comprising a single-stage conversion of an atmospheric pollutant, such as NO, NO2 and/or SOx in a first stream to one or more mineral acids and/or salts thereof by reacting with nonionic gas phase chlorine dioxide (ClO20), wherein the reaction is carried out in the gas phase. Another aspect of the invention relates to a method comprising first adjusting the atmospheric pollutant concentrations in a first stream to a molar ratio of about 1:1, and then reacting with an aqueous metal hydroxide solution (MOH). Another aspect of the invention relates to an apparatus that can be used to carry out the methods disclosed herein. The methods disclosed herein are unexpectedly efficient and cost effective, and can be applied to a stream comprising high concentration and large volume of atmospheric pollutants.

Abstract: Methods for removing sulfur dioxide front a gas stream are disclosed. A method may include passing a gas stream comprising SO2 through a gas scrubbing apparatus. A scrubbing liquor comprising hydroxide ions and at least one oxidation catalyst may be flowed into the gas scrubbing apparatus, thereby contacting the gas stream with the scrubbing liquor. In response to the contacting, at least 90 wt. % of the sulfur dioxide may be removed from the gas stream. Concomitant to the contacting, at least some of the sulfur dioxide may react with at least some of the hydroxide ions, thereby forming sulfite ions in the scrubbing liquor. Some of the sulfite ions may be oxidized, via the oxidation catalyst, thereby forming sulfate ions in the scrubbing liquor. A used scrubbing liquor may be discharged from the scrubbing apparatus.

Abstract: The present invention allows low-concentration hydrogen sulfide gas to be recovered and supplied to a processing plant that uses hydrogen sulfide gas. The hydrogen sulfide gas production plant is provided with a first supply pipe that supplies hydrogen sulfide gas obtained from a sulfur recovery facility to a processing plant, and a second supply pipe that is branched at a predetermined point in the first supply pipe and supplies the hydrogen sulfide gas from the sulfur recovery facility to the processing plant. The first supply pipe has a concentration meter that is provided on the upstream side than the branch point and measures the concentration of the hydrogen sulfide gas. The first supply pipe and the second supply pipe have ON/OFF valves that are provided on the downstream side of the branch point and perform ON/OFF control of the supply to the processing plant through the supply pipe.

Abstract: Process for preparing an aqueous cobalt sulfate solution having a pH in the range from 5 to 8, wherein (a) metallic cobalt is dissolved in aqueous sulfuric acid in an atmosphere of low-oxygen air, of hydrogen or of inert gas and (b) the resulting acidic cobalt sulfate solution is purified in an ion exchanger.

Abstract: Methane is removed from ventilation air by cycling metal or metal oxide particles in a chemical looping process in one or more reactors where the metal particles are alternately reduced and oxidized, and passing ventilation air through one or more of reactors to convert the air plus methane into reduced air, water and carbon dioxide. In one variation, a hydrogen generator and a regenerator are used to alternatively reduce and oxidize the particles such that ventilation air methane introduced into a combustor provided with hydrogen from the hydrogen generator can be processed in the regenerator to produce air, water and carbon dioxide. Other variations involve using three reactors in the chemical looping process, or an array of parallel inclined plates forming lamellas between upper and lower reactors to keep lighter particles in the upper oxidizer reactor and heavier particles in the lower reducer reactor.

Abstract: A hydrogen chloride removal process includes (i) contacting in a reactor an aqueous solution, which includes one or more Fe2+-compounds, with a fluid, which includes an oxidizing agent, hydrochloric acid gas and optionally chlorine gas; and (ii) oxidizing the Fe2+-compounds to Fe3+-compounds, thereby converting the fluid to an exhaust gas, which has a reduced hydrochloric acid content.

Abstract: A waste gas is contacted with a mercury removal agent to remove mercury and a flue gas conditioning agent to alter a resistivity and/or cohesivity of particulates. The flue gas conditioning agent can be substantially free of SO3 and/or comprise more than about 25 wt. % SO3, and/or the mercury removal agent can be substantially unaffected by the flue gas conditioning agent. An amount of mercury removed from the waste gas in the presence of the flue gas conditioning agent can be the same or more than that removed from the waste gas in the absence of the flue gas conditioning agent. An amount of the acid gas removed, by an acid gas removal agent, from the waste gas in the presence of the flue gas conditioning agent can be the same or more than that removed from the waste gas in the absence of the flue gas conditioning agent.

Abstract: A flue-gas purification system includes a flue-gas cycling system, a reacting means, and an absorbent adding system having at least a catalytic absorbent, wherein the catalytic absorbent is being gasified for reacting with the flue-gas in the reacting means in a homogenous gas-gas phase reacting manner. Therefore, the purification system has fast reaction rate between the pollutants of the flue-gas and the catalytic absorbent, which is preferably ammonia, to efficiently remove pollutants, so as to effectively purify the flue-gas.

Abstract: A mixing element positioned at an exhaust inlet of a Selective Catalytic Reduction (SCR) module is provided. The mixing element includes a base plate having a plurality of perforations thereon. The mixing element also includes a plurality of vanes connected to the base plate. Each of the plurality of vanes is spaced apart from one another. The plurality of vanes includes a plurality of flaps extending radially from the base plate. Each of the plurality of flaps has a planar configuration. The plurality of vanes also includes a plurality of blades attached to the plurality of flaps. Each of the plurality of blades extends axially with respect to an axis of the exhaust inlet. The blade has a curved configuration.

Abstract: Described is a selective catalytic reduction catalyst comprising an iron-promoted 8-ring small pore molecular sieve. Systems and methods for using these iron-promoted 8-ring small molecular sieves as catalysts in a variety of processes such as abating pollutants in exhaust gases and conversion processes are also described.

Abstract: Disclosed is a method and system for reducing the nitrogen oxide off-gas concentration in a nitric acid plant operated under pressure and equipped with a residual gas purification first reactor configured to remove nitrogen oxides from the off-gas during steady-state operation of the plant, and a second reactor configured to remove nitrogen oxides from the off-gas during a start-up and/or shut down of the plant. The method includes, during start-up and/or shut-down of the nitric acid plant, passing pressurized nitrogen-oxide-containing off-gas from the nitric acid plant and a gaseous reducing agent for the nitrogen oxides into the second reactor charged with a catalyst, to reduce the NOx content in the off-gas by at least catalytic reduction. Using the process and system, a colorless start-up and shut-down of nitric acid plants is possible and the nitrogen oxide content in the off-gas during start-up and/or shutdown can be substantially lowered.

Abstract: The invention relates to a method for upgrading a gas by separation of carbon dioxide therefrom, which method comprises the steps of introducing a stream of gas to a wet bed of ion exchange resin, and desorbing the adsorbed carbon dioxide from the resin by increasing the temperature and/or lowering the pressure in said wet bed.