Study On High Alkaline Red Mud As Resoures And Its Application

In this paper, reuse of red mud was partition into three brances:First, directive reuse of high alkaline red mud. Second, high alkaline red mud of the safe disposal and reuse. Third,red mud by the removal of sodium ions from red mud to reuse.The paper studies red mud by the interdisciplinary advantages. Red mud with high Fe2O3,by magnetic separation of red mud, through doping CuO,NiO, can be prepared with the infrared emissivity of the powder material more than 0.9 by sintering process. And through joint weak and intensity magnetic separation after the tailings into the case without grinding grade, and results obtained 47.29%, 20.09% of the recovery of fine iron powder; if after grinding, results obtained a grade of 51.32%,22.56% of the recovery of fine iron powder.In the paper, the physical properties of red mud is studied that red mud with pH 9.0 which can reduce the curing time, and red mud has a significant early strength properity.ln the red mud-hard rubber composite materials anti-corrosion, the maximum rate of weight change is only-0.4%. the state of anti-corrosion is much smaller than the standard anti-corrosion with red mud as the filling. In the reinforced rubber filler, the mixing amount of red mud in the 30 or so is appropriate. Red mud as an additive to rubber, with excellent corrosion resistance, compared to other corrosion resistant material; So it can be carried out in the corrosion industry, replacing the addition of red mud of light calcium. However, the disadvantages of red mud as a filler is, the larger proportion of red mud, and as the inorganic mineral filler basically subject to the volume filling ratio, so the red mud as the proportion of filling material advantage in terms of obvious disadvantages; Second, the relatively poor wear resistance of red mud.The third, color of red mud is quite conspicuous for performance of products; Fourth, the expansion of moisture absorption of red mud relatively strong, as a filling material, the red mud in a wet environment the problem of expansion in the case of the more prominent wetlands; Fifth, red mud as a filler, in the mechanical extrusion, the mixing process of wear and tear on equipment is relatively high. The paper verified red mud products alkaline back to surface,which can be divided into two parts, Firstly, alkali-aggregate reaction is silicate, portland cement main ingredient is calcium silicate CaSiO3. In the hydration conditions, the clinker will generate a large of Ca(OH)2, C3S, C2S and generated C-S-H at the same time a large number of free Ca2+in the water free and chek occurrence of red mud in the Na+ substitution reaction of NaOH alkali cement mortar and aggregate materials in the activity of SiO2 in enough oxygen and suitable temperature infiltration catalyzed chemical reaction, resulting in product damage. alkali aggregate reaction gel condensed matter, portland cement mortar cementing experience in the absorption of water and produce localized swelling stress, damage to the combination of cement, and furthermore the cracks, resulting in damage to portland cement materials. The main reaction:CaO+H2O→Ca(OH)2Ca(OH)2+NanC2S→C-S-H+NaOH2NaOH+SiO2→Na2SiO3+H2OMgSiO3+2NaOH→Mg(OH)2+Na2SiO3CaSiO3+2NaOH→Ca(OH)2+Na2SiO3Na2CO3+Ca(OH)2→2NaOH+CaCO3By the EDS analysis clearly identified in the sodium silicate components increased significantly, from 4.51% of cement increased to 10.28%.In red mud silicate Na+base material with water to migrate to the surface of the main driving force are capillarity. Kinetic formula is H=2fcosθ/(p.r). Then portland cement as a binder for non-conducted study found that use of early strength cement during the curing process and can be due to hydroxyl radicals and sodium alkali curing molecular reaction isNaOH+MgO+H2O→Mg(OH)2+NaOH5Mg(OH)2+MgCl2+13H20→5Mg(OH).MgCl2.8H2O. NaOHEarly strength cement with red mud is able to solidify the sodium base which is the important reasons; early strength cement curing time is short due to the rapid mobility of the slurry will be consolidated down, reducing the flow properties of the slurry; curing time is short, can quickly put the harmful substances in the consolidation of slurry reduce the flow of the main performance. EDS from the early strength of cement can be clearly seen in the physical phase of early strength cement, sodium content of 4.51% alkali, and the original red mud in the alkali content of sodium without any change in the sodium alkali early strength cement in a stable curing down.Bayer Red Mud'alkaline is the most damaging, red mud off the alkaline of the types of agents were studied on four contrast agents sodium. sodium mixed salt removal efficiency is the highest. The complexation properties of both a magnesium salt, but also has strong electrolyte ammonium salt hydrolysis class performance, red mud can quickly break the balance, removing Na+efficiency. Removing Na+removal time is not the main factors affecting the efficiency of the heating temperature, PH value of slurry of sodium removal efficiency greatly. With the removal of red mud in cement alkali content increases, the surface of the sample that returned to base, the pan-cream phenomenon belonging to a minor, showing that alkaline sodium silicate remaining reduce the impact of cement products.