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Waste incineration ash produced by burning waste generated in our daily lives is becoming a severe social problem. Recently, municipal solid waste (MSW) is treated using gasifying and melting furnace, and a large part of the molten fly ash, which is handled as a specially-controlled waste in the same manner as incineration fly ash (fly ash from stoker-type incinerators), is generated. In Japan, more than 0.1 million tons of MSW molten fly ash is estimated to be discharged every year as a result of an increasing number of MSW melting plants [1]. This molten fly ash generally contains harmful substances, especially heavy metals such as lead, zinc, and copper, and is disposed of by landfill burial after stabilization treatment by methods designated by the national government, such as chelate treatment or cement fixation. Furthermore, a shortage of landfill disposal sites has become a major social problem. The establishment of a technology which separates harmful substances such as lead, zinc, etc. in fly ash as completely as possible, and enables recycling of the residue has been desired. In addition, the content of heavy metals is usually higher than that of their respective metal ores [2]. Given this, it seems to be of great importance to develop effective separation technologies for removal and recovery of heavy metals from molten fly ash. Recently, wet processes such as acid extraction [3-5], electrodialytic separation [6], and solvent extraction [7] have been proposed for metal recovery from molten fly ash, and it was reported that these methods can be used to recover heavy metals in a highly concentrated form. Separation techniques based on dry processes such as reduced volatilization and chloride-induced volatilization has been recently proposed. In the case of reduced volatilization, separation of heavy metals from molten fly ash has been studied [1]. As a result, zinc and lead recovery levels from molten fly ash as high as 90% were achieved at 1573 K, and in addition, 99% of the dioxin content was decomposed. Furthermore, it was reported that 95% of lead and zinc were volatilized from molten fly ash in the presence of reducing agents, carbon and polyvinyl chloride (PVC) [8-12]. Moreover, to reduce energy consumption, volatilization and separation of heavy metals by chloride-induced volatilization has been studied by several researchers using CaCl2, etc. [13-16]. In general, the inorganic chlorides, NaCl, KCl, and CaCl2 are present in molten fly ash, and these inorganic chlorides are supposed to function as chlorinating agents, and the volatilization of heavy metals was found to increase with addition of inorganic chlorides and the increase became higher in order CaCl2 > NaCl > KCl [17]. This research was based on the idea that target metals of the ash can be recovered as chlorides by volatilization using waste polyvinyl chloride (PVC) as the source of chlorine and reductant. PVC is the second most important polymer worldwide and a largescale chemical product. Thanks to its excellent cost/performance ratio and outstanding chemical and environmental resistance, it is today mainly used for long-life applications. However, plastic wastes have an immense impact on the environment because plastics are non-biodegradability and take a long time to break down when they are landfill [18]. Therefore, new ways to use waste plastics are desired. PVC is composed of about 57% chlorine and about 43% hydrocarbon. It begins emitting hydrogen chloride gas by pyrolysis under 300°C and remains hydrocarbon. Hydrogen chloride gas may pose a problem during the incineration of waste, but it can be used as a provider of chlorine. Moreover, the residual Conversion Process of Molten Fly Ash into Functional Materials using Waste Plastics