Zacatecas (Mexico) Companies Extract Hg from Surface Soil Contaminated by Ancient Mining Industries
2003
Ogura, Tetsuya | Ramírez-Ortiz, Jorge | Arroyo-Villaseñor, Zenaida Maria | Hernández Martínez, Sergio | Palafox-Hernández, Jesús Pablo | García de Alba, Luis Hugo | Fernando, Quintus
In Zacatecas, Mexico, four plants are operating to extract Ag, Au, and Hg using CaS₂O₃solution from surface soil containing tailings from the amalgamation method used during 1550–1900. The metal ions extracted are cemented by scrap Cu wires. Hg is separated by evaporation from the cemented amalgam and Ag and Au are obtained from the residue. A part of the soil to be leached was separated and leached as in the industrial process. Only 121 ppm of Hg was freed from 168 ppm of extractable Hg. About a half of the remaining Hg in the soil evaporated during 18 months. This confirms that the Hg in the soil is metallic. Pb and As are also freed in the same process. It is estimated that 13 000–34 000 t of Hg had been discarded in the extraction of Ag.
显示更多 [+] 显示较少 [-]