Basic Study on the Remediation Technology
427
mercuric sulfide was added to create the specified mercury contaminated soils.
The mercury contaminated soils were placed in heat-resistant glass vessels and
heated using the test system in Fig. 1 under the conditions described above.
Figures 2 and 3 show the results. As Fig. 2 shows, when the soils were heated to
200 DC, the amount of mercury removed changed very little. However, some
mercuric sulfide in the standard sand and volcanic ash soil was removed by heat.
As Fig. 3 shows, however, when the soils were heated to 300 DC, there was a
significant change in the amount of mercury removed. Of the artificially
contaminated soils, the highest percentage of mercury was removed from the
standard sand, followed by the volcanic ash soil, and the quartz sand. Less
mercury was removed from artificially contaminated soil made with volcanic ash
soil than from artificially contaminated soil made with standard sand. This is
thought to be due to the specific heavy metals absorption capacities of the
organic substances and the soils. In oilier words, when mercuric sulfide was
contained in a volcanic ash soil relatively rich in organic substances compared to
standard sand, even when it was decomposed in the soil by heat, divalent
mercury was absorbed by the organic acids in the soil, such as humin acid, or
specifically absorbed by the clay in the soil (Cheam and Gamble 1974; Honda and
Tachikawa 1978), therefore the mercuric sulfide may not have removed smoothly.
These results show that more mercury was removed by heating when mercuric
sulfide was mixed with soil materials or in soil than when heated as pure
mercuric sulfide. However, we confirmed that the effect of mercury removal by
heat-generated evaporation differed depending on the minerals contained in the
artificially contaminated soil. The results match closely those of heating tests on
minerals containing mercury (Hamaguchi et al. 1976).
100
........
~
~ 80
Q)
Ol
~ 60
c::
~
~40
CO
>
~ 20
~
o
............... r
................ -1' ...
20
40 60 80 100
Heating time (min)
o
Fig. 2. Removal characteristics of contaminated soils heated to 200 DC
Ifide
120 140
427
mercuric sulfide was added to create the specified mercury contaminated soils.
The mercury contaminated soils were placed in heat-resistant glass vessels and
heated using the test system in Fig. 1 under the conditions described above.
Figures 2 and 3 show the results. As Fig. 2 shows, when the soils were heated to
200 DC, the amount of mercury removed changed very little. However, some
mercuric sulfide in the standard sand and volcanic ash soil was removed by heat.
As Fig. 3 shows, however, when the soils were heated to 300 DC, there was a
significant change in the amount of mercury removed. Of the artificially
contaminated soils, the highest percentage of mercury was removed from the
standard sand, followed by the volcanic ash soil, and the quartz sand. Less
mercury was removed from artificially contaminated soil made with volcanic ash
soil than from artificially contaminated soil made with standard sand. This is
thought to be due to the specific heavy metals absorption capacities of the
organic substances and the soils. In oilier words, when mercuric sulfide was
contained in a volcanic ash soil relatively rich in organic substances compared to
standard sand, even when it was decomposed in the soil by heat, divalent
mercury was absorbed by the organic acids in the soil, such as humin acid, or
specifically absorbed by the clay in the soil (Cheam and Gamble 1974; Honda and
Tachikawa 1978), therefore the mercuric sulfide may not have removed smoothly.
These results show that more mercury was removed by heating when mercuric
sulfide was mixed with soil materials or in soil than when heated as pure
mercuric sulfide. However, we confirmed that the effect of mercury removal by
heat-generated evaporation differed depending on the minerals contained in the
artificially contaminated soil. The results match closely those of heating tests on
minerals containing mercury (Hamaguchi et al. 1976).
100
........
~
~ 80
Q)
Ol
~ 60
c::
~
~40
CO
>
~ 20
~
o
............... r
................ -1' ...
20
40 60 80 100
Heating time (min)
o
Fig. 2. Removal characteristics of contaminated soils heated to 200 DC
Ifide
120 140