Study on Resistivity Characteristics and Evaluation Model of Cadmium Contaminated Laterite.

To investigate the influence characteristic of cadmium on the resistivity of laterite, the laterite samples with different water content, dry density and cadmium content were tested to analyze the relationships between the influence factors and the resistivity of laterite using the two-electrode method, and finally the resistivity evaluation model of the cadmium contaminated laterite was proposed. The results showed that the resistivity of cadmium-contaminated laterite decreased with the increasing of dry density, water content and temperature. The resistivity sharply decreased in the range of dry density less than 1.30 g⋅cm^-3, then gradually decreased and further stabilized. On the condition of different cadmium content, the resistivity gradually decreased with the increasing water content, and the most significant decrease was observed when the dry density was 1.20 g⋅cm^-3. Under the same dry density and water content, the effect of temperature above 0 °C on resistivity was not significant. The increasing cadmium gave rise to the decreasing resistivity gradually, and the change in resistivity was significant when the cadmium content was less than 100 mg⋅cm^-1. Considering the characteristics of dry density, water content and temperature comprehensively, the resistivity evaluation model of cadmium-contaminated laterite was established by the introduction of the volume water content, which had high fitting accuracy (R²=0.939 9), and the measured resistivity values were in good agreement with the model calculated resistivity values. The average mean absolute percentage error and root mean square error were 4.77% and 0.07, respectively. It could provided a theoretical model for the rapid electrical detection of heavy metal cadmium pollution in laterite areas, and it was beneficial for the quality evaluation of regional laterite cultivated land as a convenient analytical method. [ABSTRACT FROM AUTHOR]