Study on the factors affecting the leaching-out of alumina from coal refuse

For achieving a more effective leaching of alumina from the refuse in Jixi Mining Area, the refuse is subjected to pickling treatment with sulfuric acid solution after first going through thermal activation, with an aim to reveal the law governing the effect on leaching-out of alumina from refuse produced by different factors, and define the optimum alumina leaching conditions. As indicated by test result, the concentration of sulfuric acid, pickling temperature and time, and solid-liquid ratio all exert a bearing on the alumina leaching-out effect; at a liquid-solid ratio of 2∶1, a sulfuric acid concentration of 80%, a pickling temperature of 120 ℃ and a pickling time of 2.50 h, a best leaching result can be expected with an alumina leaching-out rate of being up to 37.11% in this case.