DISSOLUTION BEHAVIOR OF HARMFUL ION IN MARINE SAND

To verify the effectiveness of marine sand desalination and the accuracy of testing methods for chloride ion content from marine sand, submarine sand, desalted sea sand and seabeach sand immersed were respectively in three solvents that were deionized water, saturated calcium hydroxide, and filtrate of cement paste. The mass ratio of marine and solvent was 0.2. When the soaking time arrived at 3 h, 1 d, 7 d and 28 d, the dissolved quantities(DQ) of Cl^-、SO₄^2-、K⁺、Mg²⁺ and Na⁺ were measured. The experimental results showed that the DQ of five kinds of ion was related to the types of soaking solvents. As the soaking time went by, the DQ of Cl^- in three solvents tended to stable, and it was hard to discover the continuous dissolution, while the test value in 24 h was 14%~25% higher than that in 3 h. If marine sand was grinded into power (<75 μm), the DQ of Cl^- would decline. The dissolved mass of SO₄^2- in the filtrate of cement paste and saturated calcium hydroxide was observed to decrease with the increase of soaking time, and it was not necessary to pay close attention to the influence of SO₄^2- of sea sand concrete. Finally, the DQ of K⁺、Mg²⁺ and Na⁺ in deionized water would tend to stable with the increase of soaking time.