The invention relates to a method for extracting
indium and preparing
iron oxide by
slag-free
zinc hydrometallurgy of
zinc concentrate, which comprises the following steps of: 1, performing
fluidized bed roasting, neutral leaching, low acid leaching, purification and electrodeposition on the
zinc concentrate to prepare electric zinc; 2, performing high acid leaching, reduction, preneutralization and displacement to remove
copper on low acid leaching residue and waste
electrolyte after the electrodeposition to prepare the electric zinc; 3, neutralizing the liquid from which the
copper is removed to settle the
indium; 4, vulcanizing the liquid in which the
indium is settled to remove heavy
metal and then adding
lime milk to neutralize the liquid to obtain deeply purified liquid; 5,
settling iron in the deeply purified liquid by a hydrothermal method to obtain
hematite powder; and 6, removing impurities from the
hematite powder to obtain soft magnetic
iron oxide. In the method, the indium is settled by neutralizing and the iron is settled by the hydrothermal method, so that the indium is separated from the iron, the indium is separated from the zinc, the
hematite powder is formed, and the requirement of the soft magnetic
iron oxide is met through
impurity removal treatment. The method has the advantages of simple process, high
recovery rate of the indium and the zinc, short flow for separating the iron from the zinc, high purity of the iron, environmental friendliness, suitability for industrial application, and capability of replacing the conventional
slag-free zinc
hydrometallurgy process for extracting the indium and making effective use of the iron resource in the zinc concentrate in a form of the soft magnetic iron
oxide.