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This paper presents experimental results for liquid waste inertization in chemicaly bonded phosphate ceramic (CBPC). This process turns waste hazardous in non-hazardous waste.
It was studied the inertization of liquid wastes containing heavy metals (Ba, Cd, Cu, Ni, Pb) with concentrations between 3000 mg/l and 30000 mg/l in CBPC versus inertization in portland cement paste. As the CBPC is a fast setting system, it was also used boric acid as retarder in concentration of 3% (based on the amount of magnesium oxide and potassium dihydrogen phosphate). To increase the efficiency of cadmium inertization, phosphoric acid was added. Also it was studied the influence of sodium dimetilditiocarbamate. It was determined the maximum temperature of the obtained systems, the setting time and compression strength. To determine the effectiveness of waste inertization it was performed leaching tests in water and in acid solution, and the obtained values were compared with regulated limits.
Lucrarea prezintä rezultatele experimentale pentru inertizarea deseurilor lichide în lianti magneziano-fosfatici (CBPC). Prin acest proces deseurile periculoase se transformä în deseuri nepericuloase.
S-a studiat inertizarea deseurilor lichide cu continut de metale grele (Ba, Cd, Cu, Ni, Pb) cuprins între 3000 mg/l si 30000 mg/l, în CBPC comparativ cu inertizarea în pastä de ciment portland. Deoarece sistemul CBPC este unul cu întârire rapidä, s-a utilizat ca întârzietor de prizä acidul boric în concentrare de 3% (raportat la cantitatea de oxid de magneziu si fosfat diacid de potasiu). Pentru a märi eficienta inertizärii cadmiului s-a adäugat acid fosforic. De asemenea, s-a studiat influenta adäugärii dimetilditiocarbamatului de sodiu. S-a determinat temperatura maximä a sistemelor obtinute, timpul de început de prizä si rezistenta la compresiune. Pentru determinarea eficientei procesului de inertizare a deseurilor s-au realizat teste de levigare în apä si în solutie acidä, valorile obtinute comparându-se cu cele reglementate.
Keywords: waste inertization, heavy metals, chemically bonded phosphate ceramic, CBPC, portland cement, leachate, TCLP
1. Introduction
According to the legislation, the liquid wastes are not accepted for storage in the waste deposits. They must be previously treated, stabilized, solidified. The non-hazardous waste landfill permit the storage of stable, non-reactive hazardous waste, such as those solidified vitrified, having a proper leaching behavior [1].
Stabilization processes change the dangerousness of the waste components and therefore transform hazardous waste into a non-hazardous...