Study on Properties of Copper-Contaminated Soil Solidified by Solid Waste System Combined with Cement

Abstract

Three industrial solid wastes including red mud, carbide slag, and phosphogypsum combined with ordinary Portland cement were used as curing agents to solidify/stabilize loess polluted by a high concentration of copper ions. The unconfined compressive strength, resistivity, permeability coefficient, copper ion leaching concentration, pH value, and other engineering application evaluation indexes were analyzed to preliminarily assess the applicability of the curing agent in the remediation of soil contaminated with a high concentration of copper ions. The mineral phases and functional groups of solidified soil were detected using XRD and FTIR, showing that the strength, electrical resistivity, and pH value of solidified soil decrease following the addition of copper ions. Moreover, the strength and resistivity of solidified soil increase with the curing age, and the pH value decreases with age. For solidified contaminated soil, when the total content of curing agent increases from 10 to 20%, the maximum 28 d strength increases from 1.35 to 5.43 MPa, and in this study, its permeability coefficient, copper ion leaching concentration, and pH value were found to be within the limits set by relevant national standards. In conclusion, red mud-carbide slag-phosphogypsum combined with cement has a good stabilizing effect on sites polluted with a high concentration of copper ions.

Strength Characteristics and Micro-Mechanism of Silty Soil Modified by Red Mud Co-Cement

“…A German Bruker D8 Advance X-ray diffractometer was used in the test. The test parameters were set as follows: the working voltage is 20 to 60 kV, the working current is 10 to 300 mA, the constant step size is 0.002 • to 90 • , the scanning rate is 0.002 to 100 • /min, and 2θ the angle test range is 5 • to 80 • [16].…”

Fiber Solidification Treatment of River and Lake Wastewater and Sediments: Deformation Characteristics and Microscopic Mechanism Research

“…Common solidifying agents for solidified soil include cement, quicklime, and fly ash. Numerous scholars have conducted experiments employing various methods, with a primary emphasis on saline soil [3][4][5][6][7][8], loess [9][10][11][12][13][14], and other typical soil types [15][16][17]. The existing studies show a comparatively limited focus on the solidification of dredged sediment from rivers and lakes.…”