Experimental Evaluation of PM Emission from Red Mud Basins Exposed to Wind Erosion

Abstract

The disposal of industrial and mineral processing residues represents a major concern for human health and the environment as a whole. In order to reduce the impact on soil and groundwater due to the waste leachability, the implementation of environmental regulations worldwide has favored the conversion of the disposal techniques from wet to dry (i.e., dry stacking or dry disposal). Such a change in the storage practice may cause the increase of particulate matter (PM) emission from the dry surfaces of the tailings exposed to wind erosion. Considering the significance of the environmental issue on a global scale and the increasingly stricter orientation of environmental policies, the need for modeling tools capable of estimating the contribution of tailing basins to air pollution becomes apparent. The paper deals with the disposal of red mud resulting from the bauxite processing in the alumina industry. An experimental research was carried with an environmental wind tunnel to estimate the Emission Factor (EF) of the basin surfaces as a function of the main affecting variables (i.e., residue water content and wind velocity). The article reports the results of the experimental test carried out on the red mud from a major basin located in Sardinia (Italy).

Emission of Fine Dust from Open Storage of Industrial Materials Exposed to Wind Erosion

“…, which is commonly used to describe the results of experimental tests performed on a variety of granular materials exposed to wind erosion [3,9,11,[41][42][43][44][45]. The correlation factor (R 2 ) was found between 0.98 and 0.99, which proves the power law function to be accurate in the description of the F D -u * relationship.…”

“…The threshold friction velocity (u *t ) obtained by means of experimental tests performed in the DICAAR environmental wind tunnel [11,37] is lower for the PbS samples (Table 1).…”

“…The probabilistic approach, as alternative to the empirical algorithms already proposed by the technical and scientific literature [9][10][11][12][13][14][15][16][17]; -…”

“…In that case, determination of the overall dust flow (F D ) requires the preliminary partialization of the complex surface (S) into homogeneous elementary surfaces (S i ), each characterized by a specific emission factor (F Di ). That methodology, recently discussed for the wide and inhomogeneous surfaces of a red mud basin [11], allows us to determine the overall emission flow (F D ) as sum of the elementary contributions (F Di ): the overall flow (F D ) associated to a complex emitting surface is a key input data in the simulation of PM dispersion performed with numerical codes.…”

Synergistically Using Bauxite Residue (Red Mud) and Other Solid Wastes to Manufacture Eco-Friendly Cementitious Materials

“…Currently, the annual disposal amount of RM has reached over 60 million tons, and over 1.3 billion tons in total are stacking in China, but with a recycling rate lower than 5% [1]. In Europe, dry stacking storage of RM was started about 50 years ago, and even at present, there are still many stacking storage places existing in Europe [2,3], and the negative effects of RM stacking have created significant environmental concerns.…”