Toda Kogyo Corporation

Junichi Kawano

Kenji Okinaka

Masayuki Uegami

Tomoko Okita

Koji Kakuya

Hideaki Sadamura

Katsumi Yamashita

Yasuhiko Fujii

Minoru Yamasaki

Tosiharu Harada

Haruki Kurokawa

Tomohisa Moriya

Andreas D Jazdanian

Soichi Yatagai

Soichi Yatagi

Kazuhisa Inaba

Iron composite particles for purifying soil or ground water, comprise &#x3b1;-Fe and magnetite, and having a ratio of a diffraction intensity Dof (110) plane of &#x3b1;-Fe to a sum of a diffraction intensity Dof (311) plane of magnetite and the diffraction intensity D(D/(D+D)) of 0.30 to 0.95 as measured from X-ray diffraction spectrum of the iron composite particles, an Al content of 0.10 to 1.50% by weight and an S content of 3500 to 7000 ppm; a process for producing the iron composite particles; a purifying agent containing the iron composite particles; a process for producing the purifying agent; and a method for purifying soil or ground water.

Iron composite particles for purifying soil or ground water, process for producing the same, purifying agent containing the same, process for producing the purifying agent and method for purifying soil or ground water

A purifying agent for purifying soil or ground water which comprises a water suspension containing iron composite particles comprising &#x3b1;-Fe and magnetite, and having an average particle diameter of 0.05 to 0.50 &#x3bc;m, an S content of 3500 to 10000 ppm and an Al content of 0.10 to 1.50% by weight, and polyaspartic acid or a salt thereof. The purifying agent is capable of decomposing aliphatic organohalogen compounds or aromatic organohalogen compounds contained in the soil or ground water in an efficient, continuous and economical manner.

Purifying agent for purifying soil or ground water, process for producing the same, and method for purifying soil or ground water using the same

Iron particles for purifying soil or ground water of the present invention comprise a mixed phase of &#x3b1;-Fe phase and FeOphase, and having a BET specific surface area of 5 to 60 m/g, an Fe content of not less than 75% by weight based on the weight of the iron particles and a sulfur content of not less than 1,000 ppm. The iron particles are capable of decomposing or insolubilizing harmful substances such as organohalogen compounds and/or heavy metals, cyanogen, etc. contained in the soil or ground water in efficient, continuous and economical manners.

Process for purifying contaminated soil or groundwater with iron particles

Iron particles for purifying contaminated soil or ground water

The disclosure describes a process for producing Co-coated acicular magnetite particles each comprising: acicular magnetite particle as the core particle; a lower coating layer of Co-containing spinel ferrite having a spinel structure, which is formed on the surface of said acicular magnetite particle; and an upper coating layer of Co- and Mg-containing spinel ferrite having a spinel structure, which is formed on said lower coating layer.

Process for producing co-coated acicular magnetite particles

Co-coated acicular magnetite particles each comprising: acicular magnetite particle as the core particle; a lower coating layer of Co-containing spinel ferrite having a spinel structure, which is formed on the surface of said acicular magnetite particle; and an upper coating layer of Co- and Mg-containing spinel ferrite having a spinel structure, which is formed on said lower coating layer.

Co-coated acicular magnetite particles and process for producing the same

Disclosed herein are a process for producing acicular goethite particles comprising the steps of: blowing an oxygen-containing gas into a ferrous salt reaction solution containing colloidal ferrous hydroxide or iron-containing colloidal precipitates which is obtained by reacting an aqueous ferrous salt solution with less than one equivalent of an aqueous alkali hydroxide solution and/or an aqueous alkali carbonate solution based on Fe.sup.2 + in said aqueous ferrous salt solution so as to oxidize said colloidal ferrous hydroxide or iron-containing colloidal precipitates and to produce acicular goethite nucleus particles, adding to the resultant aqueous ferrous salt reaction solution containing said acicular goethite nucleus particles not less than one equivalent of an aqueous alkali carbonate solution based on Fe.sup.2 + in said aqueous ferrous salt reaction solution, and blowing an oxygen-containing gas into the mixed aqueous ferrous salt reaction solution so as to grow said goethite nucleus particles; and a process for producing acicular magnetic iron oxide particles by reducing the acicular goethite particles obtained in the above process to produce acicular magnetite particles, and if necessary, oxidizing the acicular magnetite particles to obtain acicular maghemite particles, and if necessary, modifying the acicular magnetite or maghemite particles with Co or Co and Fe.sup.2 +.

Process for producing acicular goethite particles and acicular magnetic

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Onoda, Japan

Junichi Kawano