고형연료제품의 유해중금속 분석을 위한 마이크로파 산 분해법의 개선

The quality standards of solid refuse fuel (SRF) define the values for 12 physico-chemical properties, including moisture,lower heating value, and metal compounds, according to Article 20 of the Enforcement Rules of the Act on ResourceSaving and Recycling Promotion. These parameters are evaluated via various SRF Quality Test Methods, but problemsrelated to the heavy metal content have been observed in the microwave acid digestion method. Therefore, these methodsand their applicability need improvement. In this study, the appropriate testing conditions were derived by varying theparameters of microwave acid digestion, such as microwave power and pre-treatment time. The pre-treatment of SRF asa function of the microwave power revealed an incomplete decomposition of the sample at 600 W, and the heavy metalcontent analysis was difficult to perform under 9 mL of nitric acid and 3 mL of hydrochloric acid. The experiments withthe reference materials under nitric acid at 600 W lasted 30 minutes, and 1,000 W for 20 or 30 minutes were consideredoptimal conditions. The results confirmed that a mixture of SRF and an acid would take about 20 minutes to reach 180oC, requiring at least 30 minutes of pre-treatment. The accuracy was within 30% of the standard deviation, with a precisionof 70 ~ 130% of the heavy metal recovery rate. By applying these conditions to SRF, the results for each condition werenot significantly different and the heavy metal standards for As, Pb, Cd, and Cr were satisfied.