FATES OF RADIOACTIVE ARSENIC, CESIUM, STRONTIUM AND ORGANO-CHLORINE DURING THE GASIFICATION OF MIXED WASTES IN THE PRESENCE OF ORGANIC-MATTER

Radioisotopes of arsenic, cesium, strontium and chlorine were mixed wi th organic matter to make mixed radioactive/hazardous wastes and gasif ied to destroy the organic fractions on a macroporous char matrix in a laboratory-scale version of cocurrent flow waste gasification. Except for chlorine, gasified as chlorobenzene on untreated char, essentiall y all the radionuclides were retained in the gasifier on the char resi due. Complete retention of chlorine was obtained by treating the char with sodium hydroxide. Condensate from the gas product and char from a filter used to filter the gas can be recirculated through the system as additional assurance of zero release of radioactive substances. The spent char from the gasifier can be regasified with additional wastes , resulting in a concentration of radioactive substances onto char, wh ich can eventually be converted to a nonleachable slag for ultimate di sposal. (C) 1998 Elsevier Science Ltd. All rights reserved.