Preparation For A Flue Gas Desulfurizer With White Mud From Soda Plant And Red Mud From Steel Plant

Based on increasing SO₂ pollution in China and the industry waste pollution caused by White Mud(W for short)from Soda Plant and Red Mud(R for short)from Steel Plant, the preparation for a flue gas desulfurizer with W from Soda Plant and R from Steel Plant is studied. Drying, crushing and sieving the W and M, joining a few body aids, to prepare molding desulfurizer which is strong, then Flue Gas Desulfurizion(FGD) activity tests are carried out in fixed bed reactor. In order to improve the preparation technics of desulfurizer and SO₂ capacity, the ratio of W and M, body aids content and preparation methods et al are reviewed. XRD is studied to review desulfurizer components, TG is studied to review desulfurizer capability, and thereby the desulfurizion mechanism is studied thoroughly. The uses of desulfurizion production are researched too.The components and content of raw materials are analyzed: The W from Qingdao Soda Plant contains CaCO₃ 53.21%; The M from Qingdao Steel Plant contains iron-oxide 66.57% in all, some CaCO₃ and MgO as well.The result shows that effective components of both are rich, that is fit for preparing fule gas desulfurizer.According to the components and character of W and M, the function and need quantity of every body aids as well, the feasible content that main materials are 90% and the body aids are 10% is ascertained. The best ratio of main materials is W:M=2:1(wt%), that is to say, W 60%, M 30%. The main materials are the finer the better, the molding desulfurizer is strong and effective when particulates more than 40 mesh. The best components and feasible content of body aids are binders-kaoline 5%, pore-making agents-starch 4.9%, lube-graphite 0.1%. According to the above chosen desulfurizer components and content, desulfurizer is made intoφ3mm and 2～5cm in length after mixing well-proportioned in water and crushing it strip-shaped in extrusion press. The desulfurizer which dried at 105℃for 6h,then calcined at 400℃in muffle, has best desulfurizion effect. It has been found that there is no influence on desulfurizion when desulfurizer is calcined for 1～5h.The optimal reaction conditions of desulfurizer are reviewed. Those shows:the desulfurizer must react in a high temperature, the desulfurizion effect is very good in 350～600℃,and the higher the better.The airspeed has a great effect on desulfurizion, the less the greater in 600～1400 h-1. The SO₂ Content in fule gas has a certainty effect on desulfurizion, the more the better. The H2O Content in fule gas also has a great effect on desulfurizion, the best content is 4%, more or less is not well. The O₂ Content in fule gas has a great effect on desulfurizion too, the more the better, until 6% in best.XRD shows: in course of preparing desulfurizer, Calcining in 400℃makes FeO and Fe3O4 in material into active Fe₂O₃, which is favourable for desulfurizion reaction. The reaction temperature of dusulfurizer made with W is the higher the better in 350～600℃as well as dusulfurizer added with M, and the addition of M is more beneficial to defulfurizion. In the same desulfurizion temperature(400℃),the desulfurizion effect of desulfurizer [B₆C₃]⁴⁰NaZ_bR-G₄₀₀² is the best when the ratio of W and M is 2:1.TG shows: in 20～600℃, the quality of desulfurizer made with W and M has a little change, which implies that the desulfurizer has high heat-stability. The heat-stability of desulfurizer after-desulfurizion is better than that before-desulfurizion, so the used desulfurizer can be applied in filling groundsill, construsting road, building sea dam and so on.By many angles such as XRD, accounting and comparing practice saturation SO₂ capacity with theory saturation SO₂ capacity, chemistry analysis, the truth that desulfurizion production is not Fe2(SO4)3 at all is confirmed. Moreover, desulfurizion mechanism is speculated, namely, the iron-oxide in M has a stimulative effect on desulfurizion,it can be explained with catalyse oxidation mechanism and activity focus mechanism. The desulfurizion mechanism is not clear thoroughly, some problems still need further investigation.The aim of this paper is to carry out united FGD with W from Soda Plant and M from Steel Plant, and the good effect is conformed. This task"treat waste by waste", makes the economy and environmental protection win-win. It has a very practical significance in China.