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

Abstract

Iron composite particles for purifying soil or ground water, comprise α-Fe and magnetite, and having a ratio of a diffraction intensity D 110 of (110) plane of α-Fe to a sum of a diffraction intensity D 311 of (311) plane of magnetite and the diffraction intensity D 110 (D 110 /(D 311 +D 110 )) of 0.30 to 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.

1 .- 18 . (canceled) 
     
     
         19 . A method for purifying soil or ground water, comprising:
 mixing and contacting the iron composite particles comprising α-Fe and magnetite, and having a ratio of a diffraction intensity D 110  of (100) plane of α-Fe to a sum of a diffraction intensity D 311  of (311) plane of magnetite and the diffraction intensity D 110  (D 110 /(D 311 +D 110 )) 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 with soil or ground water, which are contaminated with organohalogen compounds, heavy metals or the like, or both thereof.   
     
     
         20 . A method for purifying soil or ground water, comprising:
 mixing and contacting the iron composite particles comprising a water suspension containing iron composite particles as an effective ingredient which comprise α-Fe and magnetite and have a ratio of a diffraction intensity D 110  of (110) plane of α-Fe to a sum of a diffraction intensity D 311  of (311) plane of magnetite and the diffraction intensity D 110  (D 110 /(D 311 +D 110 )) of 0.20 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, an S content of 3500 to 7000 ppm, an average particle diameter of 0.05 to 0.5 μm and a particle diameter of coarse particles of usually 0.5 to 5.0 μm with soil or ground water, which are contaminated with organohalogen compounds, heavy metals or the like, or both thereof.   
     
     
         21 . A method for purifying soil or ground water, comprising:
 comprising a water suspension containing iron composite particles as an effective ingredient which comprise α-Fe and magnetite, and have a ratio of a diffraction intensity D 110  of (110) plane of α-Fe to a sum of a diffraction intensity D 311  of (311) plane of magnetite and the diffraction intensity D 110  (D 100 /(D 311 +D 110 )) of 0.20 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, an S content of at least 3500 ppm, a saturation magnetization value of 60 to 155 μm 2 /kg, a crystallite size of (110) plane of α-Fe of 200 to 400 Å, an Fe content of not less than 65% by weight based on the weight of whole particles, an average particle diameter of 0.05 to 0.5 μm and a particle diameter of coarse particles of usually 0.5 to 5.0 μm, mixing and contacting the iron composite particles as defined in claim  7  with soil or ground water, which are contaminated with organohalogen compounds, heavy metals or the like, or both thereof.