%L eprintuntirta46143 %A Pramudya Fascal Satria %A MOCHAMAD FANDITO UTOMO %T PEMANFAATAN KALSIUM PADA STEEL SLAG DAN FOSFOR PADA LIMBAH KULIT MELINJO SEBAGAI PUPUK KALSIUM FOSFAT %X Banten Province produces waste from steel processing or known as steel slag of 1.4 million tons per year. This area is also known for the large amount of melinjo crops, this makes melinjo skin waste quite abundant. The two wastes have only been used in a fairly limited field, where steel slag is only used in the construction sector and melinjo leather waste is only used as processed food. The two wastes still contain elements that can be used in agriculture in large quantities, the content is calcium in steel slag and phosphorus in melinjo skin waste. This study aims to extract calcium in steel slag and phosphorus in melinjo skin waste and then use it into high-phosphorus calcium chloride fertilizer. In addition, this study also aims to determine the type of extraction and the best operating conditions to extract the two elements. The method used in this study is extraction using strong acids. The results obtained in this study are calcium phosphate fertilizer products with calcium content of 0.93% and phosphate 0.19% where these levels are still below SNI, the best type of extraction to extract phosphorus is H2SO4 with a phosphorus content of 148.96 ppm, and the best temperature and time for calcium extraction from steel slag is 65°C and the time is 30 minutes with the average mass of CaCO3 produced is 39.663 gr at temperature and 32.533 gr at time %D 2024 %I Fakultas Teknik Universitas Sultan Ageng Tirtayasa