The material studied, a waste fly ash from the metallurgical
industry, contains the toxic element As in high concentrations,
ranging from 23% to 47% (wt %). Besides As, Sb
and Pb are present in the waste material. The waste
was solidified with inorganic materials such as cement
and pozzolanic materials in order to reduce the leachability
of the contaminants from the waste. The optimal
solidification recipe lowered the As concentration in the
leachate of the extraction test DIN 38 414 S4 from ca. 5 g/L
to ca. 5 mg/L. In this paper, it was shown that this
enormous reduction in As concentration was due to the
formation of CaHAsO3 in the leachate, in the presence of Ca-
(OH)2. Formation of CaHAsO3 alone cannot lower the
arsenic concentration beneath ca. 55 mg/L, as was calculated
with the speciation program MINTEQA2
The material studied, a waste fly ash from the metallurgicalindustry, contains the toxic element As in high concentrations,ranging from 23% to 47% (wt %). Besides As, Sband Pb are present in the waste material. The wastewas solidified with inorganic materials such as cementand pozzolanic materials in order to reduce the leachabilityof the contaminants from the waste. The optimalsolidification recipe lowered the As concentration in theleachate of the extraction test DIN 38 414 S4 from ca. 5 g/Lto ca. 5 mg/L. In this paper, it was shown that thisenormous reduction in As concentration was due to theformation of CaHAsO3 in the leachate, in the presence of Ca-(OH)2. Formation of CaHAsO3 alone cannot lower thearsenic concentration beneath ca. 55 mg/L, as was calculatedwith the speciation program MINTEQA2
การแปล กรุณารอสักครู่..
