5 results about "Selenous acid" patented technology

The application discloses a treatment method for efficiently removing selenium from waste acid, and specifically comprises the following steps: preheating waste acid to be treated for removing selenium, adding sulfuric acid to adjust the H + concentration of 4-6 mol / L, then adding a reducing agent sodium sulfite Na2SO3, and fully stirring and mixing; controlling the temperature to be 55-70 DEG C to perform a first-stage reaction, then adding a composite catalyst prepared by mixing sodium thiosulfate Na2S2O3 and iodine I2, stirring and mixing, continuing to perform a deep reaction, and performing solid-liquid separation after filtration when the reaction is completed. The application uses sodium sulfite reduction, iodine and sodium thiosulfate catalysis as a substitute for the traditional SO2 reduction mode, solves the problem that the traditional SO2 reduction method is limited by pH liquid, accelerates the reaction rate through iodine and sodium thiosulfate catalysis, simultaneously solves the problem that the traditional sulfite cannot reduce selenium-containing substances other than selenite, and improves the reduction effect of selenium.

This invention discloses a selenite crystal and its preparation method. X-ray powder diffraction of the selenite crystal, measured using Cu-Kα radiation, yielded diffraction angles (expressed as 2θ) of 17.7°±0.2°, 19.5°±0.2°, 20.0°±0.2°, 22.9°±0.2°, 24.5°±0.2°, 24.9°±0.2°, 26.2°±0.2°, 29.8°±0.2°, 30.2°±0.2°, 31.4°±0.2°, and 33°. Characteristic peaks are observed at 0°±0.2°, 34.3°±0.2°, 35.8°±0.2°, 36.6°±0.2°, 37.4°±0.2°, 37.5°±0.2°, and 38.4°±0.2°. A characteristic endothermic peak is observed at 73.4℃ in the differential scanning calorimetry (DSC) spectrum of the crystal. This invention features a simple preparation route, mild reaction conditions, convenient operation, low cost, and good process reproducibility. The prepared selenite has a stable crystal form, making it suitable for large-scale industrial production of pharmaceutical raw materials.

The application provides a method for preparing 6N selenium from 2N selenium, and belongs to the field of high-purity metal preparation.The method comprises the following steps: oxidizing and roasting 2N selenium to obtain selenium dioxide vapor; mixing the selenium dioxide vapor with water to perform a combination reaction to obtain a selenite solution; mixing the selenite solution with a reducing agent to perform a reduction reaction to obtain 3N and / or 4N selenium; melting the 3N and / or 4N selenium, and then immersing a crystallizer into the obtained melt to perform rotary crystallization to obtain 6N selenium.The application roasts selenium with oxygen to generate selenium dioxide to remove high-boiling impurities; the selenium is enriched by using the property that selenium dioxide is easily soluble in water, the impurities (such as selenium dioxide) that are difficult to dissolve in water are removed to realize the purification of selenium; the 3N and / or 4N selenium is further purified by rotary crystallization to realize the further purification of selenium.

The application discloses a selenium catalytic synthesis method of polylactic acid in the technical field of material chemistry. L The amount of the substituted selenous acid as the catalyst precursor added into the lactic acid is 0.02-0.08% of the mass of the lactic acid. L The amount of the substituted selenous acid as the catalyst precursor added into the lactic acid is 0.02-0.08% of the mass of the lactic acid. L The amount of the substituted selenous acid as the catalyst precursor added into the lactic acid is 0.02-0.08% of the mass of the lactic acid. 3 The polylactic acid can be obtained by blowing the material into a flow of 0.4-1.0 cm / s air and heating at 160-180 DEG C. The method is simple, and the use of metal catalysts can be avoided, so that metal residues in the product are eliminated, and medical-grade polylactic acid material can be directly prepared.

This invention provides a method for preparing a selenite-sulfide nanocomposite material. Nickel selenite is grown in situ on nickel-plated carbon cloth using a hydrothermal method, followed by electrodeposition of transition metal sulfides onto its surface. Selenite, as a reinforcing phase in the positive electrode material of a supercapacitor, improves the conductivity of the composite material and releases selenate ions, which, along with sulfate ions released from the sulfides, adsorb onto the material surface, promoting redox kinetics in the electrochemical process. The prepared selenite-sulfide composite nanoelectrode material exhibits excellent supercapacitor performance at a current density of 1 A g. ‑1 At that time, its specific capacity was 3509 F g. ‑1 An asymmetric supercapacitor composed of commercially available activated carbon at 844 W / kg ‑1 The power density reached 141Wh / kg. ‑1 High energy density. This supercapacitor exhibits good cycle stability at 5A g. ‑1 Under these conditions, after 25,000 cycles, the capacity retention rate was 100.2%.