A sulfidic complexing agent is disclosed that includes a suspension or a solution formed by a reaction between a water-soluble metal compound and a water-soluble sulfidic compound. The sulfidic complexing agent has a pH of from about 5 to about 11 and a molar ratio of metal to sulfur of from about 0.1 to about 1,000. The sulfidic complexing agent is useful for removing elemental mercury from a hydrocarbon fluid by contacting the hydrocarbon fluid with the sulfidic complexing agent. The molar ratio of sulfur in the sulfidic complexing agent to mercury in the hydrocarbon fluid is from about 50 to about 2,500. Also disclosed is a method for concurrently transporting and removing a trace amount of volatile mercury in a CO.sub.2-containing natural gas stream extracted from a subterranean formation. The natural gas stream is transported in a pipeline into which the sulfidic complexing agent is injected. Also disclosed is a method for capturing gas phase elemental mercury from a gas stream in the overhead section of a crude oil distillation unit by contacting the gas stream with the sulfidic complexing agent in the overhead section of the distillation unit to form a treated gas stream.

Disclosed are various methods for reducing levels of elemental sulfur within gypsum products such as wall board. Gypsum sometimes includes increased levels of elemental sulfur. Such sulfur can be corrosive and otherwise harmful at elevated levels. The disclosure contemplates reacting the elemental sulfur with copper to copper sulfide. This reaction has the benefit of reducing the levels of elemental sulfur present within the final gypsum product. The copper can be added at any of a variety of locations in the manufacturing process. This is a very efficient method for reducing elemental sulfur in the production of gypsum products.

Disclosed are various methods for reducing levels of elemental sulfur within gypsum products such as wall board. Gypsum sometimes includes increased levels of elemental sulfur. Such sulfur can be corrosive and otherwise harmful at elevated levels. The disclosure contemplates reacting the elemental sulfur with copper to copper sulfide. This reaction has the benefit of reducing the levels of elemental sulfur present within the final gypsum product. The copper can be added at any of a variety of locations in the manufacturing process. This is a very efficient method for reducing elemental sulfur in the production of gypsum products.

Provided is a method of manufacturing high-purity, high-quality manganese sulfate which can be immediately used for manufacturing a lithium ion secondary battery from manganese sulfate waste liquid of a wasted battery. Since impurities are removed from the manganese sulfate waste liquid by using sulfides causing no secondary contamination in the manganese sulfate waste liquid and the manganese sulfate is manufactured by performing evaporation concentration through heating, the manufacturing method is very environment-friendly and economical. Since the manganese recovering process improving the manufacturing yield of the manganese sulfate and the waste water treatment process capable of recycling the source materials and discharging waste water are integrated, the manufacturing method is very efficient and environment-friendly. The manufacturing method is applied to the recycling industry, and thus, it is possible to obtain effects of preventing environmental pollution and facilitating recycling the resources.

The present disclosure relates to a semiconductor nanoparticle composite film including semiconductor nanoparticles and diamond-like carbon (DLC), the composite film satisfying at least one selected from the group consisting of: i) the composite film includes mainly the semiconductor nanoparticles; and ii) at least a portion of the semiconductor nanoparticles are arranged in line. The composite film can be obtained by, for example, irradiating a semiconductor nanoparticle-containing film including semiconductor nanoparticles and a carbon source with an ion beam to generate DLC. The carbon source includes an organic compound other than a polymer.

The present disclosure relates to a semiconductor nanoparticle composite film including semiconductor nanoparticles and diamond-like carbon (DLC), the composite film satisfying at least one selected from the group consisting of: i) the composite film includes mainly the semiconductor nanoparticles; and ii) at least a portion of the semiconductor nanoparticles are arranged in line. The composite film can be obtained by, for example, irradiating a semiconductor nanoparticle-containing film including semiconductor nanoparticles and a carbon source with an ion beam to generate DLC. The carbon source includes an organic compound other than a polymer.

A method for separating arsenic and heavy metals in an acidic washing solution which contains both arsenic and heavy metal, more particularly in a washing solution which is formed in copper smelting and contains sulphuric acid, comprises a separation process section, in which arsenic and at least one primary heavy metal are separated from one another. The separation process section comprises a processing step, in which hydrogen peroxide H2O2 is added to the washing solution, and the separation process section comprises a precipitation stage, in which the washing solution is admixed with a sulphide precipitation reagent, causing the at least one primary heavy metal to precipitate in the form of a metal sulphide. The processing step in this system is carried out before the precipitation stage.

A method for separating arsenic and heavy metals in an acidic washing solution which contains both arsenic and heavy metal, more particularly in a washing solution which is formed in copper smelting and contains sulphuric acid, comprises a separation process section, in which arsenic and at least one primary heavy metal are separated from one another. The separation process section comprises a processing step, in which hydrogen peroxide H2O2 is added to the washing solution, and the separation process section comprises a precipitation stage, in which the washing solution is admixed with a sulphide precipitation reagent, causing the at least one primary heavy metal to precipitate in the form of a metal sulphide. The processing step in this system is carried out before the precipitation stage.

This method for leaching an electrode material is a method for subjecting an electrode material of a lithium ion secondary battery to acid leaching, the method including a leaching step of reacting the electrode material of a lithium ion secondary battery with sulfuric acid to obtain a leachate in which metals contained in the electrode material are leached, in which the leaching step includes a sulfuric acid adding step of adding the sulfuric acid to the electrode material to obtain a sulfuric acid-added electrode material, a kneading step of kneading the sulfuric acid-added electrode material to form a leaching paste, and a diluting step of diluting the leaching paste with water.

This method for leaching an electrode material is a method for subjecting an electrode material of a lithium ion secondary battery to acid leaching, the method including a leaching step of reacting the electrode material of a lithium ion secondary battery with sulfuric acid to obtain a leachate in which metals contained in the electrode material are leached, in which the leaching step includes a sulfuric acid adding step of adding the sulfuric acid to the electrode material to obtain a sulfuric acid-added electrode material, a kneading step of kneading the sulfuric acid-added electrode material to form a leaching paste, and a diluting step of diluting the leaching paste with water.