Extraction of Iron and Manganese from Pyrolusite Absorption Residue by Ammonium Sulphate Roasting–Leaching Process

Abstract

The residue from desulfurization and denitrification of exhaust gas treatment process with pyrolusite ore as absorbent is regarded as a potential source of iron and manganese. In this study, an extraction process is proposed for recovery of iron and manganese with ammonium sulphate roasting followed by sulphuric acid leaching. Firstly, the conversion mechanism was analyzed through mineral phase analysis of roasting products at different roasting temperature by means of X-ray diffraction (XRD) technology. Then, the parameters of the roasting procedure such as roasting temperature and time, ammonium sulphate dosage, leaching temperature, leaching time, and sulphuric acid concentration are examined. The results implicate that the iron oxide and manganese dioxide in the residue are firstly converted into the water-soluble (NH 4 ) 3 Fe(SO 4 ) 3 and (NH 4 ) 2 Mn 2 (SO 4 ) 3 at 200-350 • C, and then the more stable NH 4 Fe(SO 4 ) 2 and MnSO 4 are formed, at temperature higher than 350 • C. Under optimum conditions, 95.2% Fe and 97.0% Mn can be extracted. Reactant diffusion through inert layer of silicon dioxide was considered as the rate-limiting step for iron extraction with an activation energy of 20.56 kJ/mol, while, the recovery process of Mn was controlled by both reactant diffusion and chemical reaction with an activation energy of 29.52 kJ/mol.

The Recovery of TiO2 from Ilmenite Ore by Ammonium Sulfate Roasting–Leaching Process

“…Several years ago, some studies investigated the extraction of metals from different minerals by using the ammonium sulfate roasting method. These minerals included vanadium slag [31], bauxite ore [32], spent lithium-ion batteries [33], manganese ore [34], and nickel sulfide ores [35]. Some studies have been conducted on ilmenite ore using ammonium sulfate roasting.…”

Processing of Alluvial Deposit Sands with a High Content of Copper and Nickel Using Combined Enrichment Technology

“…A lot of attention is paid to the use of ammonium sulfate, which is due to its high reactivity when interacting with non-ferrous metal sulfides (the interaction mechanism was described in our previous reports) [22]. The low-temperature sulfide roasting process with ammonium sulfate has been successfully applied globally to various types of mineral feeds [23], such as lateritic and sulfide nickel ores [24,25], bauxite [26], oxidized zinc [27], manganese ores [28]. In general, the enrichment operations have been carried out on a laboratory scale.…”