[en] Bauxite tailings is a by products material derived from bauxite ore beneficiation. The beneficiation process is done by separating the particles that exist such as mud or clay, roots, bauxite ore grain ranges from 2 mm are discarded or be referred as a waste product or tailings. High concentration of alumina and silica in bauxite tailings are considered as one of the reasons why they can be used as base material in the making new products, namely synthetic zeolite. Synthetic zeolite is selected because zeolites are imported, expensive and have uniform properties and >150 types of synthetic zeolites can be made commercially and even in industrial zeolite can be used widely as an adsorbent, ion exchange, membranes, catalysts, etc. The chemical analysis of bauxite tailing showed the composition of alumina (Al₂O₃) is approximately 49.41 %, while silica (SiO₂) and hematite (Fe₂O₃) are about 12.58 % and 10.6 % respectively, and also some other inorganic oxides are in small amounts. The conversion process of bauxite tailings into zeolite is carried out by caustic fusion method to extract the fusion (alumina precursor) followed by the addition of sodium silicate precursor with synthesis formula 1.2Na₂O.0.5SiO₂.0.5Al₂O₃.10H₂O. Products crystallization is carried out by hydrothermal method at low temperature with specified variable incubation period. The results showed that the zeolite synthesis of bauxite tailings using caustic fusion and followed by crystallization at low temperature and under atmospheric pressure has succeeded in transforming the product from an amorphous phase to the crystalline phase product zeolite adsorbent. (author)