Focused on the issues of red mud utilization and road building material shortage, this paper put forward the research idea of utilizing red mud as the succedaneum of limestone powder to prepare asphalt mixture. Modification methods which included inorganic powder blending (cement, slaked lime) and organic coupling agent surface modification (silane coupling agent KH-550, KH-560) were proposed with the view of solving moisture sensitivity of red mud-bitumen interface, with the influence of modification means on performance of red mud asphalt mixture were also studied. The performance of red mud asphalt mixture before and after modification were systematically evaluated by using dynamic stability test, Marshall test, Hamburg rut test, dynamic modulus test and two-point bending fatigue test. It was found that the red mud could improve the high-temperature performance of asphalt mixture, but had negative effects on the moisture stability, cracking resistance and fatigue life. After red mud modification, the high and low temperature performance, moisture stability and long-term durability of red mud asphalt mixture were improved to varying degrees, and the surface modification effect of silane coupling agent performed better. It was proved the feasibility of using red mud to produce asphalt mixture and provided a new approach for red mud utilization.

In order to study the adsorption characteristics of ball clay, the effect of adsorption time, ball clay dosage, pH values and initial concentration of Cu(Ⅱ) were examined by the batch experiments. The results suggested that the adsorption of Cu(Ⅱ) on ball clay was a fast and then slow process. Which almost achieved adsorption equilibrium after 60 minutes and the adsorption capacity and adsorption rate were increased with the increase of ball clay dosage and initial concentration of Cu(Ⅱ). The pH value had a great impact on the adsorption of ball clay and when the pH value was 6, the adsorption capacity was obtained over 97.93 mg/g. The adsorption of Cu(Ⅱ) on the ball clay followed the Langmiur isotherm model, and the maximum adsorption capacity obtained was 202.383 mg/g. The pseudo-second-order kinetics model was more suitable to describe the adsorption process of Cu(Ⅱ), which indicated that the adsorption rate was controlled by chemisorption. Compared with other pure clay adsorbent materials, the ball clay had a high ability to adsorb copper ions and could be used as a natural mineral adsorbent to treat industrial wastewater containing copper ions.

In order to study the effect of screw extrusion mechanism on the dewatering efficiency of food waste, a micro element discrete model connecting material characteristics and screw extrusion device parameters was constructed, combined with numerical simulation, the four factors affecting the dehydration efficiency of the unit, such as the initial moisture content of materials, the filling degree of materials, the form of spiral blades and the spiral speed, were theoretically calculated. In the process of building the model, the parameter scheme with relatively optimal dehydration efficiency was selected by using the analysis method of orthogonal test. The conclusion provided a theoretical basis for the design and selection of screw extrusion mechanism. The calculation results showed that the screw speed and material filling degree had a significant impact on the dehydration efficiency of the unit, and the maximum dehydration rates were up to 40% and 40.6%. The initial moisture content of materials and the form of spiral blades had little influence on the dehydration efficiency of the unit, and the maximum dehydration rates were only 16.6% and 14.8%. The orthogonal test results showed that the moisture content at the end of the material was 69.7% for variable pitch helical blade structure, under the condition that the initial moisture content of the material was 80%, the material filling coefficient was 75%, and the screw speed was 15 r/min. Considering the factors such as energy consumption, work efficiency and cost performance, the parameter condition had the most advantages in the actual working conditions.