Study On The Preparation And Performance Of Red Mud-based Corrosion-inhibiting Snow Melting Agent

The demand for snow melting agents in many countries and regions are increasing with the increase of snowfall.Snow melting agent can quickly melt snow,which is currently the most widely used snow removal technology.Chloride-type snow melting agents are most used due to their low price,rapid snow melting and wide range of sources.However,with the wide range of chlorine salt snow melting agents,chloride ions cause irreversible damage to soil,vegetation,water bodies and roads and bridges.In this paper,a corrosion inhibitor with its own freezing point was prepared.On the basis of retaining the characteristics of rapid melting and melting of the chloride salt type snow melting agent,the impact of chloride ion on the ecological environment and infrastructure was reduced.Simultaneously,it also utilized the solid waste produced by the aluminum industry-red mud.The detailed research contents are as follows:(1)First,the iron-aluminum in the red mud is recovered as a nitrate by a method of hydrochloric acid and nitric acid leaching.The extracted aluminum nitrate and magnesium nitrate were used as raw materials,and then Mg Al-LDHs and Mg Al Fe-LDHs were synthesized under hydrothermal conditions.The optimum Mg/Al molar ratio and hydrothermal temperature were determined on the basis of fixing other reaction conditions.After calcination at a high temperature of 500 °C,Mg Al-CLDH and Mg AFe-CLDH deicing inhibitors are obtained;(2)The structural characteristics were determined by characterization of Mg Al-LDHs and Mg Al-CLDH.After high temperature calcination,CLDH exhibits an adsorption capacity for anions and has a "memory effect".By studying the removal ability of Mg-LDHs and Mg Al-CLDH at room temperature and low temperature,and comparing the corrosion inhibition performance of the two materials,then selecting a corrosion inhibitor with strong corrosion inhibition ability;(3)By characterizing the structural characteristics of Mg Al Fe-LDHs and Mg Al Fe-CLDH,the characteristics,surface morphology and structure of Mg Al Fe-LDHs and Mg Al Fe-CLDH after Fe3+ incorporation were determined,and the effect of CLDH on the anion effect was determined,too.Comparative analysis of theremoval rate of Cl-at room temperature and low temperature by Mg Al Fe-LDHs and Mg Al Fe-CLDH indicates the corrosion inhibition and adsorption capacity of the two materials.By comparing the corrosion inhibition performance of Mg Al-CLDH and Mg Al Fe-CLDH,it is finally determined that Mg Al Fe-CLDH is an additive of mixed snow melting agent;(4)A snow melting agent in which Ca Cl2 and Mg Al Fe-CLDH were mixed in a ratio of 1:1 was prepared under the conditions of low chloride salt content and good freeze resistance.Taking the various specifications of the snow melting agent in the national standard GB/T 23851-2009 as a reference,determine a series of snow melting performance of the mixed snow melting agent p H value,freezing point range and snow melting capacity.At the same time,the optimization of corrosion in the mixed snow melting agent was analyzed by the rotary hanging method and the concrete anti-salt method.The mechanism of snow melting of mixed snow melting agent was analyzed by XRD characterization method.The anti-corrosion mechanism of mixed snow melting agent was further studied.