Abstract: There is provided an iron arsenate powder which is produced from an arsenic containing solution and wherein the concentration of arsenic eluted or released from the powder is very low. The iron arsenate powder is a powder of dihydrate of iron arsenate, which has a crystal structure of rhombic system and which has lattice constants of a=0.8950 to 0.8956 nm, b=1.0321 to 1.0326 nm and c=1.0042 to 1.0050 nm at room temperatures and atmospheric pressure. The iron arsenate powder can be produced by a method comprising the steps of: adding ferrous ions to an arsenic containing solution to cause the molar ratio (Fe/As) of iron to arsenic in the solution to be not lower than 1; adding an oxidizing agent to the solution; heating the solution to a temperature of not lower than 70° C. while stirring the solution, to allow a reaction; and carrying out a solid-liquid separation to wash the obtained solid part.

Abstract: To provide a method of generating, with good reproducibility and ease and without complicated operations, scorodite which satisfies the elution standard (in accordance with Notification of No. 13 of Japanese Environment Agency) and which has good filterbility and stability for processing arsenic contained in a diarsenic trioxide form. A method of processing diarsenic trioxide, including: a leaching step of adding water to diarsenic trioxide to produce slurry, heating the slurry, and leaching arsenic while adding an oxidant to obtain leachate; a deoxidization step of removing the oxidant so as to obtain an adjusted solution; and a crystallizing step of converting arsenic in the adjusted solution to scorodite crystal.

Abstract: To provide a method of generating, with good reproducibility and ease and without complicated operations, scorodite which satisfies the elution standard (in accordance with Notification of No. 13 of Japanese Environment Agency) and which has good filterbility and stability for processing arsenic contained in a non-ferrous smelting intermediate, particularly, for processing a diarsenic trioxide form. A method of processing diarsenic trioxide, including: a leaching step of adding water and alkali to a non-ferrous smelting intermediate that contains diarsenic trioxide to produce slurry, heating the slurry, and leaching arsenic; a solution adjusting step of adding an oxidizing agent to the leachate to oxidize trivalent arsenic to pentavalent arsenic so as to obtain an adjusted solution; and a crystallizing step of converting arsenic in the adjusted solution to scorodite crystal.

Abstract: Provided is a method of easily producing easily-filterable and stable scorodite that meets the leaching standard (conformance to Japanese Environmental Agency Notice 13) with excellent reproducibility and without using complex operations, when processing arsenic that is included in non-ferrous smelting intermediates, and particularly when processing arsenic in the form of a sulfide. Scorodite is produced by a leaching step of leaching arsenic from a non-ferrous melting intermediate containing arsenic in the weakly acid region, a solution adjusting step of oxidizing trivalent arsenic to pentavalent arsenic by adding an oxidizing agent to the leaching solution, and a crystallizing step of converting the arsenic in the adjusted solution to scorodite crystals.

Abstract: The object is to remove arsenic in a stable form from an arsenic-containing smelting intermediate product. Thus, disclosed is a method for treating an arsenic-containing nonferrous smelting intermediate product, which comprises: a leaching step of subjecting a mixed slurry of a nonferrous smelting intermediate product containing arsenic in the form of a sulfide and a nonferrous smelting intermediate product containing arsenic and metal copper to the oxidation/leaching in an acidic range to produce a leaching solution; a solution preparation step of adding an oxidizing agent to the leaching solution to oxidize trivalent arsenic into pentavalent arsenic, thereby producing a preparation solution; and a crystallization step of converting arsenic contained in the preparation solution into a scorodite crystal.

Abstract: Provided is a method of easily producing scorodite which is stable and has excellent filtering properties with excellent reproducibility and without using complex operations, when processing arsenic that is included in non-ferrous smelting intermediates, and particularly when processing copper arsenic compounds in the form of an intermetallic compound. Scorodite is produced by a leaching step of leaching arsenic from a non-ferrous melting intermediate containing a copper arsenic compound in the form of an intermetallic compound in the presence of a sulfidizing agent and an oxidizing agent, a solution adjusting step of oxidizing trivalent arsenic to pentavalent arsenic by adding the oxidizing agent to the leaching solution, and a crystallizing step of converting the arsenic in the adjusted solution to scorodite crystals.

Abstract: To provide a recovery agent for recovering arsenic, fluorine, lead, and selenium from a solution containing environmentally hazardous substances including arsenic and fluorine. A porous iron oxide having a particle size of 10 to 100 ?m and a specific surface area of 50 m2/g or larger determined by three-point BET method is introduced into a solution containing the environmentally hazardous substances. Alternatively, a solution containing the environmentally hazardous substances is passed through a column filled with the porous iron oxide. Thus, the environmentally hazardous substances are recovered from the solution.

Abstract: A method of producing an iron-arsenic compound by adding an oxidizing agent to an aqueous solution containing arsenic ions and bivalent iron ions and allowing an iron-arsenic compound precipitation reaction to proceed under stirring of the solution, wherein the precipitation reaction is terminated at a solution pH in the range of 0 to 1. When the arsenic concentration of the pre-reaction solution is 25 g/L or greater, the reaction can be terminated at a solution pH in the range of ?0.45 to 1.2. The pH of the pre-reaction solution is preferably greater than 0 and not greater than 2.0. A ferrous sulfate is can be used as the source of the bivalent iron ions. Even when some amount of impurity elements is present in the arsenic-containing solution, the method is nevertheless capable of forming a scorodite compound excellent in crystallinity in the form of a compact compound barely swollen by moisture and the like, i.e., a niron-arsenic compound excellent in filterability.

Abstract: Provided is an arsenic-containing solid comprising 100 parts by mass of a scorodite-type iron-arsenic compound and at least 1 part by mass of an iron oxide compound added thereto, in which the scorodite-type iron-arsenic compound is produced by adding an oxidizing agent to an aqueous acidic solution that contains a 5-valent arsenic (V) ion and a 2-valent iron (II) ion, then promoting the precipitation of an iron-arsenic compound with stirring the liquid, and finishing the precipitation thereof within a range where the pH of the liquid is at most 1.2. The iron oxide compound includes goethite, hematite and their mixture, preferably having a BET specific surface area of at least 3 m2/g, more preferably at least 20 m2/g.

Abstract: A difference of work functions in different metal thin films is suppressed without causing the increase of the manufacturing steps or the decrease of the optical performance. In a semi-transmissive reflective liquid crystal display apparatus 1 including a reflective electrode 62 and a transmissive electrode 63 in the pixel electrode 64, the surface of the reflective electrode 62 is subject to a plasma treatment, so that the work function of the reflective electrode 62 is controlled by changing by a value of 0.1 eV from the original value. Thus, it is possible to place the work function of the reflective electrode 62 within a difference of ±0.2 eV with respect to the work function of the transmissive electrode 63. As a result, a number of the manufacturing steps is not increased or no optical performance is decreased, unlike conventional liquid crystal display apparatuses.

Abstract: The present invention provides a semi-transmissive liquid crystal display device that can suppress flicker by adjusting an optimum value of a direct-current offset voltage that is applied to offset a bias electric field generated inside liquid crystal without increasing the number of production steps, and also provides a preferable production method of the semi-transmissive liquid crystal display device. The liquid crystal display device of the present invention is a semi-transmissive liquid crystal display device including: a substrate on aback face side, including a transmissive electrode and a reflective electrode; a substrate on an observation face side, facing the substrate on the back face side; and a liquid crystal layer arranged between the substrate on the back face side and the substrate on the observation face side, wherein the reflective electrode has a molybdenum-containing surface on a side of the liquid crystal layer.

Abstract: An active matrix substrate (30) of the present invention includes (i) a plurality of TFT elements (2) provided on an insulating substrate (10), and (ii) pixel electrodes (7) electrically connected to the plurality of TFT elements (2), respectively. The pixel electrodes (7) has (i) a first transparent electrode layer (7a), (ii) a reflective electrode layer (7b) stacked on the first transparent electrode layer (7a), which reflective electrode layer (7b) has a smaller area than that of the first transparent electrode layer (7a), and (iii) a second transparent electrode layer (7c) stacked so as to cover at least the reflective electrode layer (7b). Hence, it is possible to realize a transflective liquid crystal display device which suppresses occurrence of a flicker, thereby having high display quality.

Abstract: There is provided an iron arsenate powder which is produced from an arsenic containing solution and wherein the concentration of arsenic eluted or released from the powder is very low. The iron arsenate powder is a powder of dihydrate of iron arsenate, which has a mean particle diameter of not smaller than 8 micrometers, preferably not smaller than 10 micrometers, and a BET specific surface area of not greater than 2 m2/g, preferably not greater than 0.5 m2/g, and wherein the percentage of particles having particle diameters of not greater than 5 micrometers of the powder is not greater than 10%, preferably not greater than 5%. The amount of each of calcium and magnesium contained as impurities in the iron arsenate powder is preferably not greater than 2% by weight.

Abstract: In a semi-transmissive liquid crystal display device (50a) including an active matrix substrate (20a), the active matrix substrate (20a) includes a plurality of source lines (2), a first transparent electrode (2c) connected to each source line (2) through a TFT (5), an interlayer insulating film (12) provided on the first transparent electrode (2c) and having an opening (12a), a reflective electrode (6) provided on the interlayer insulating film (12) and connected to the first transparent electrode (2c) through the opening (12a), and a second transparent electrode (7a) overlapping the reflective electrode (6a) and the first transparent electrode (2c) and connected to the reflective electrode (6a) and the first transparent electrode (2c). In each pixel, respective outer peripheral ends (E) of the reflective electrode (6a) and the second transparent electrode (7a) are aligned with each other.

Abstract: A method of producing an iron-arsenic compound by adding an oxidizing agent to an aqueous solution containing arsenic ions and bivalent iron ions and allowing an iron-arsenic compound precipitation reaction to proceed under stirring of the solution, wherein the precipitation reaction is terminated at a solution pH in the range of 0 to 1. When the arsenic concentration of the pre-reaction solution is 25 g/L or greater, the reaction can be terminated at a solution pH in the range of ?0.45 to 1.2. The pH of the pre-reaction solution is preferably greater than 0 and not greater than 2.0. A ferrous sulfate is can be used as the source of the bivalent iron ions. Even when some amount of impurity elements is present in the arsenic-containing solution, the method is nevertheless capable of forming a scorodite compound excellent in crystallinity in the form of a compact compound barely swollen by moisture and the like, i.e., a niron-arsenic compound excellent in filterability.

Abstract: There is provided a method for recovering a powder of a compound of iron and arsenic, which has a very low concentration of arsenic eluted from the powder, by treating an arsenic containing solution, e.g., a high purity and high concentration arsenic containing solution obtained by treating an arsenic containing substance which contains various elements other than arsenic, such as an intermediate product in a non-ferrous metal smelting or refining process. Ferrous ions are added to an arsenic containing solution, which contains 10 g/L or more of arsenic, so as to cause the ratio (Fe/As) of iron to arsenic in the solution to be not less than 1, and an oxidizing agent is added to the solution to allow a reaction at a temperature of not lower than 70° C. while stirring the solution. Then, a solid-liquid separation is carried out, and a solid part separated by the solid-liquid separation is dried.

Abstract: Aluminum sulfate that is less colored is prepared by adjusting the concentration of hydrogen peroxide in sulfuric acid to 0.1% by weight or less, and contacting the sulfuric acid with an alumina-containing compound.

Abstract: It has been believed that the Claus reaction in water without additive gives no more than very low conversion and some additive such as buffer or catalyst must be used to attain satisfactory H.sub.2 S conversion.However, it was discovered that when H.sub.2 S and SO.sub.2 are introduced in water simultaneously and continuously for hours, the conversion increased gradually and became steady at high level. The present invention was accomplished base on this inventive knowledge.

Abstract: An aerator comprises an air diffuser rotor for receiving air and forcing out the air through small perforations formed in its peripheral wall, and an agitator-pump unit rotatably disposed immediately above the rotor. When the aerator is installed on the bottom of a waste water purifying tank, the agitator-pump unit raises water from the bottom of the tank and produces a circulating flow of water through the interior of the tank, while the air diffuser rotor forces out air bubbles into the circulating flow, whereby an improved aeration efficiency can be achieved.