ISSN: 1003-6326
CN: 43-1239/TG

Vol. 23    No. 8    August 2013

Synthesis of nickel ferrite precursors from low grade nickel matte
Li-hua HE1, Zhong-wei ZHAO1, You-xin ZHANG1,2
(1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Jinchun Group Co., Ltd., Jinchang 737104, China
Abstract: Fine nickel ferrite precursors NiFe2(C2O4)3·6H2O were obtained via co-precipitation method with low grade nickel matte as the raw material. Thermodynamic analysis of NiCl2-FeCl2-(NH4)2C2O4-H2O system for precipitation identified that the theoretical optimum co-precipitation pH value is 2, and has strong complexation with Ni2+ and Fe2+ ions. Based on these theoretical considerations, the effects of parameters on the precipitation rates and precursors size were investigated systematically. The results show that the optimum co-precipitation conditions are pH=2, temperature 45 °C, 1.2 times theoretical amount of (NH4)2C2O4 dosage and 3% PEG400 addition. Under these conditions, the precipitation rates of Ni2+ and Fe2+ are both over 99.8%, with the precursors size of 1-2 um. Furthermore, X-ray diffraction (XRD) and thermogravimetry-differential thermal analysis (TG-DTA) demonstrate that the precursors are single-phase solid solution, wherein the nickel/iron atoms are replaced by the iron/nickel atoms reciprocally.
Key words: nickel ferrite; ferrite; magnetic materials; co-precipitation; low grade nickel matte
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)