24 fuel cell. The presence of Ce in the earth's crust is higher than copper (66.5 ppm) and lead (60 ppm) [8]. Ce in nature has two different ionic states, the trivalent and tetravalent Ce which is beneficial for increasing the photocatalystic performance [9]. Tetravalent Ce tends to be more stable than trivalent [8]. The main resources of rare earth elements that have been processed are monazite, xenotime, and bastnaesite [10]. Among the three types of minerals, the lowest amount of cerium was in xenotime while cerium content in monazite was similar to bastnaesite, which was 46-49 % of Ce [11]. Tin mining activities in Bangka produced tin ingot and other forms of tin metal products through the smelting and