Patent ID: 7482384

Claim:
A purifying agent for soil or ground water, comprising a water suspension containing as an effective ingredient iron composite particles comprising α-Fe and megnetite, 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 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 at least 3500 ppm, a saturation magnetization value of 85 to 155 Am 2 /kg, a BET specific surface area of 5 to 60 m 2 /g, a crystallite size of (110) plane of α-Fe of 200 to 400 Å, an Fe content of not less than 75% by weight based on the weight of whole particles.