The present invention relates to a method of preparing an iron-chromium oxide using an ion-exchange resin. Moreover, the present invention relates to a method of preparing an iron-chromium oxide that can be used as a cathode material for lithium-ion batteries. According to one aspect of the present invention, it has the effect of providing a cathode material for lithium-ion batteries with a high capacitance, while exhibiting a voltage similar to that of a transition-metal oxide (2-4.5 V vs Li.sup.+/Li).

The present disclosure provides a method for separating iron element in brine and application thereof. The method for separating iron element in brine comprises: adding a pH adjusting agent to brine, to adjust pH of the brine to 6.0-7.0, and controlling the temperature of the brine to 75° C.-90° C.; introducing an oxygen-containing gas into the brine, to covert the iron element in the brine into magnetic iron oxide; and separating the magnetic iron oxide from the brine by magnetic adsorption to obtain an iron-removed brine.

Techniques including methods and apparatuses for selective measurement and monitoring of halide concentrations in processing solutions for iron triad metals and their alloys are provided. Methods include monitoring of a halide ion, for example, based on a first analytical method such as conductivity with a compensation of the results for a main metal concentration such as a second analytical measurement of concentration of an iron triad metal (e.g., nickel (Ni)). From such measurements, a concentration of certain halide ions can be selectively determined.

The present invention relates to a method of purifying waste hydrochloric acid, and more particularly, to a method of purifying waste hydrochloric acid which includes preparing an extraction solution by dissolving an extractant in an organic solvent (S1), extracting metallic components with the organic solvent by adding the extraction solution to the waste hydrochloric acid (S2), separating a waste hydrochloric acid layer and the organic solvent containing the metallic components (S3), and obtaining purified hydrochloric acid by recovering the separated (fractionated) waste hydrochloric acid layer (S4), wherein the extractant is used in an amount of 40 moles or more based on 1 mole of iron (Fe) included in the waste hydrochloric acid, and the waste hydrochloric acid and the extraction solution are mixed in a volume ratio of 1:0.1 to 1:1.

A method for purifying ferric chloride, the method including: 1) adding an oxidant to an aqueous solution of an iron-containing chloride for oxidation of Fe.sup.2+, to yield a ferric chloride solution; 2) adding industrial hydrochloric acid and butyl acetate to the ferric chloride solution, shaking and resting a mixture of the ferric chloride solution, the industrial hydrochloric acid, and butyl acetate for phase separation, to yield an organic phase and an aqueous phase; 3) adding a stripping agent to the organic phase, shaking, and resting a mixture of the stripping agent and the organic phase; and collecting an aqueous phase including ferric chloride; and 4) evaporating and concentrating the aqueous phase including ferric chloride, removing butyl acetate, to yield purified ferric chloride.

A magnetic recording medium includes: a substrate; and a magnetic layer including a ferrimagnetic particle powder. A product (V×SFD) of a particle volume V and a holding force distribution SFD of the ferrimagnetic particle is equal to or less than 2500 nm3.

Provided is a method for inhibiting extractant degradation in the DSX process through the metal extraction control, the method comprising steps of: (a) adding limestone to a copper solvent extraction-raffinate to precipitate iron (Fe) and aluminum (Al) as a slurry, recovering a clarifying liquid; and (b) adding sulfuric acid to the recovered clarifying liquid to adjust the pH thereof.

A preparation method of pearlescent pigment coating materials is provided. The method of the present invention lies in that titanium-iron ions in ilmenites are dissolved by using a hydrochloric acid at a certain temperature and pressure, and then ferrous chloride in the acidolysis solution is precipitated by adding hydrogen chloride gas, the remaining titanium-iron ions are separated from other colored ions by means of co-extraction using an extractant upon oxidation, and an enriched titanium oxydichloride solution and ferrous hydrous oxide are obtained by employing a fractional back extraction and enrichment method, the titanium oxydichloride solution can be used for mica-titanium based pearlescent pigment coating materials, and can also be used for preparing titanium dioxide; and the acidified ferrous hydrous oxide and the oxidized ferrous chloride can be used as iron based pearlescent pigment coating materials or used for preparing iron oxide pigments.

The invention relates to sulfonated aminomethylated chelate resins, to a method for producing same, to the use thereof for obtaining and purifying metals, in particular rare earth metals, from aqueous solutions and organic liquids, and for producing highly pure silicon.

A method for purifying ferric chloride, the method including: 1) adding an oxidant to an aqueous solution of an iron-containing chloride for oxidation of Fe.sup.2+, to yield a ferric chloride solution; 2) adding industrial hydrochloric acid and butyl acetate to the ferric chloride solution, shaking and resting a mixture of the ferric chloride solution, the industrial hydrochloric acid, and butyl acetate for phase separation, to yield an organic phase and an aqueous phase; 3) adding a stripping agent to the organic phase, shaking, and resting a mixture of the stripping agent and the organic phase; and collecting an aqueous phase including ferric chloride; and 4) evaporating and concentrating the aqueous phase including ferric chloride, removing butyl acetate, to yield purified ferric chloride.