Impact of Cl- on Environment When Industrial Soda Residue is Applied in Highway Project

摘要

In China, a great amount of soda residue is brought out annually by enterprises which make soda production by ammonia-soda process. The free chloride ion in the residue may bring secondary pollution into the surrounding environment, when the residue is used for the construction of highway project. For that reason, the impact of free chloride ion on the surrounding environment and ground water had been studied through measuring chemical composition of soda residue, analyzing physical and chemical interaction mechanism of free chloride ion with soda residue-lime stabilized soil and the solidified additive agent, and also considering the practice of highway construction. The results show free chloride ion dissolution in soda residue-lime stabilized soil in road base and sub-base is limited and it is produce local pollution to the base soil other than produce the pollution to a large area of soil and groundwater. Because free chloride ion in soda residue can interact with active composition in stabilized soil and can be absorbed and transformed when the ratio of the soda residue is less than 16%. The concentration can be below 18g/kg (dry base). The maximum absorbability of soil to chloride ion is 1.6g/kg. When the level of the ground water is 2m higher than sub-base, the chloride ion in highway base can dissolve, subsequently can be completely absorbed by base soil even though the destroyed highway cannot be repaired in time. The conclusion can be draw from above that it is able to meet Chinese highway construction trade standards and environmental standards, when industrial soda residue is applied in highway project instead of calcareousness.