A mixer for recirculating ash from solid fuel combustion with hydrated lime and water and to feed the mixture into a desulfurization reactor. The mixer includes a housing having a front wall, two outer vertical sidewalls, a rear wall, a top, and a bottom, the top includes a feed chute configured for the entry and addition of product to the mixer, and the front wall includes an opening for the mixture of product to exit. The mixer also includes a rotatable vertical shaft having an impeller, the impeller having a plurality of blades disposed on the vertical shaft in the same horizontal plane and distributed equidistantly about the circumference of the vertical shaft. The mixer also includes a vertical wall disposed within the housing forming a mixing region and a feeding region that is operably connected to the opening of the front wall.

A method for the reduction and prevention of mercury emissions into the environment from combusted fossil fuels or other off-gases with the use of peracetic acid is disclosed. The peracetic acid is used for the capture of mercury from the resulting flue gases using a flue gas desulfurization system or scrubber. The method uses peracetic acid in conjunction with a scrubber to capture mercury and lower its emission and/or re-emission with stack gases. The method allows the use of coal as a cleaner and environmentally friendlier fuel source as well as capturing mercury from other processing systems.

The disclosure provides seven integrated methods for the chemical sequestration of carbon dioxide (CO.sub.2), nitric oxide (NO), nitrogen dioxide (NO.sub.2) (collectively NO.sub.x, where x=1, 2) and sulfur dioxide (SO.sub.2) using closed loop technology. The methods recycle process reagents and mass balance consumable reagents that can be made using electrochemical separation of sodium chloride (NaCl) or potassium chloride (KCl). The technology applies to marine and terrestrial exhaust gas sources for CO.sub.2, NOx and SO.sub.2. The integrated technology combines compatible and green processes that capture and/or convert CO.sub.2, NOx and SO.sub.2 into compounds that enhance the environment, many with commercial value.

The present invention discloses a process for preparing sulfur from reduction of sulfate/nitrate by iron-carbon and recovering desulfurization/denitration agents. High-concentration SO.sub.2 flue gas produced by calcination of a sulfate and NOx produced by heating decomposition of a nitrate can be directly reduced to elemental sulfur vapor and N.sub.2 through reaction with an iron-carbon material at a high temperature. Then, after dust removal, cooling and fine dust removal, sulfur is recovered by a sulfur recovery device, and metal oxides can replace alkaline mineral resources such as limestone as raw materials of desulfurization (denitration) agents. This process can recycle the desulfurization and denitration agents.

The present invention discloses a method for preparing iron ore concentrates by recycling copper smelting slag tailings, and belongs to the technical field of metallurgy and tailings recycling. In the present invention, copper slag tailings obtained after copper pyrometallurgy and flotation and water are used as raw materials, and low-concentration sulfur dioxide flue gas is used as a leaching agent for leaching of metals such as iron, zinc, copper, arsenic, and silicon in the slag tailings; the leachate is purified step by step through processes such as replacement by metal iron powder and sulfide precipitation control, to separate zinc, copper, arsenic, etc.; a purified solution is mainly composed of FeSO.sub.4 or can be used for producing a ferric salt flocculant; obtained tailings are used to obtain iron ore concentrates through magnetic separation, and the obtained iron ore concentrates can be used for further producing ultra-pure iron ore concentrates.

The removal of acid gases (e.g., non-carbon dioxide acid gases) using sorbents that include salts in molten form, and related systems and methods, are generally described.

A mixer for recirculating ash from solid fuel combustion with hydrated lime and water and to feed the mixture into a desulfurization reactor. The mixer includes a housing having a front wall, two outer vertical sidewalls, a rear wall, a top, and a bottom, the top includes a feed chute configured for the entry and addition of product to the mixer, and the front wall includes an opening for the mixture of product to exit. The mixer also includes a rotatable vertical shaft having an impeller, the impeller having a plurality of blades disposed on the vertical shaft in the same horizontal plane and distributed equidistantly about the circumference of the vertical shaft. The mixer also includes a vertical wall disposed within the housing forming a mixing region and a feeding region that is operably connected to the opening of the front wall.

Marine engine exhaust includes pollutants such as CO.sub.2, NO.sub.x and SO.sub.x. An onboard system and method for the simultaneous removal of these pollutants includes obtaining seawater from the water on which the marine vessel travels, purifying the seawater to remove a portion of hard ions, concentrating the seawater to yield a concentrated brine solution, treating the concentrated brine solution with a chemical softener to yield a treated brine solution, acidifying the treated brine solution, and utilizing the acidified brine solution in a chlor-alkali process to yield sodium hydroxide. The sodium hydroxide can be used in an acid gas scrubber to remove CO.sub.2, NO.sub.x, and SO.sub.x from the marine engine exhaust gas.

A method and a facility for wet-scrubbing sulfur dioxide to produce, for example, potassium thiosulfate or ammonium thiosulfate. The facility includes a multi-section vessel having multiple horizontally disposed stages where a preceding stage passes partially-scrubbed waste gas to a succeeding stage. Each stage has a scrubber mechanism to scrub waste gas with circulating fluid that successively reduces waste gas concentration before atmospheric discharge. The scrubber mechanism may include a packing to facilitate absorption of waste gas by the fluid, a sump disposed at the output of the stage to receive fluid as it drains from the packing, and a circulation pump to circulate fluid from the sump to its packing and to cascade at least a portion of the fluid back to a preceding stage. A portion of the fluid is extracted from the facility and reacted in a reaction vessel with a cation to produce ammonium thiosulfate or potassium thiosulfate.

The present invention discloses a process for preparing sulfur from reduction of sulfate/nitrate by iron-carbon and recovering desulfurization/denitration agents. High-concentration SO.sub.2 flue gas produced by calcination of a sulfate and NOx produced by heating decomposition of a nitrate can be directly reduced to elemental sulfur vapor and N.sub.2 through reaction with an iron-carbon material at a high temperature. Then, after dust removal, cooling and fine dust removal, sulfur is recovered by a sulfur recovery device, and metal oxides can replace alkaline mineral resources such as limestone as raw materials of desulfurization (denitration) agents. This process can recycle the desulfurization and denitration agents.