In the present work, recycling of bottom ash from both industrial waste and municipal solid waste incinerators (MSWI) was investigated. In order to recycle bottom ash as raw materials for cement production, it is necessary to remove chloride, which causes metal erosion in reinforced concrete. Therefore, experiments for removing chloride were carried out by washing bottom ash in order to obtain efficient washing conditions. The following conditions were investigated: pH, type of solution, particle size, bubbling and temperature. Although pH is the most effective parameter for reducing Cl content in ash, using acid to lower pH is not an environmental friendly treatment considering wastewater treatment. It was found that CO₂, bubbling in the form of microbubble is a proper treatment to decompose insoluble chloride as an environmental friendly treatment.