Development of Metal Recovery Process for Municipal Incineration Bottom Ash (MIBA)

Abstract

The utilization of incineration ash from municipal waste must be promoted to solve the social problem on the shortage of final disposal site. In this research, metals should be recovered to avoid the damage of the crushing machine during the utilization of incineration ash in cement industry. In fact, incineration bottom ash from municipal waste contains iron in 3-5%. Nonferrous metal and stainless steel in 1% is also included. The research and development on the physical recovery process was performed not only to remove the metals but also to recover high grade products. Metals were separated from incineration ash in Maruya Co. Ltd.. In fact, iron scrap recovered by magnetic separation can be selled. After that, mixed metal was separated from incineration ash using screen. In this research, mixed metal tried to divided copper, aluminum, brass and stainless steel using drum type magnetic separation, eddy current separation and high magnetic separation. As a result, recovered iron had an 80% for the grade. Aluminum was recovered by eddy current separation without copper and brass.

Fig. 1. Separation experiment flow.

Fig. 2. Separation experiment flow (Improvement process).

Fig. 3. XRF analysis result of magnetic material recovered by magnetic separation.

Fig. 4. XRF analysis result of magnetic material recovered by drum type magnetic separation.

Fig. 5. XRF analysis result of flying substance recovered by eddy current separation.

Fig. 6. XRF analysis result of magnetic material recovered by high magnetic separation (30 mm above).

Fig. 7. XRF analysis result of magnetic material recovered by high magnetic separation (30 mm above).

Table 2. Recovered materials and mass fraction

Table 1. Experimental condition