Selective separation of sodium from red mud with citric acid leaching

ABSTRACT

Selective separation of sodium with citric acid leaching from red mud has been put forward. The main factors and dealkalization mechanism by using inductively coupled plasma atomic emission spectroscopy, X-ray diffraction, and shrinking core model were studied. The results show that the dealkalization rate reached more than 95% under the following conditions: citric acid dosage of 15%, liquid-to-solid ratio of 7 mL/g, leaching temperature of 100°C, stirring speed of 300 rpm, and leaching time of 120 min. Sodium easily dissolved in the solution by citric acid leaching. The dealkalization process was controlled by internal diffusion and the apparent activation energy (E_a) was 19.43 kJ/mol.

KEYWORDS:

• Citric acid leaching
• eco-friendly technology
• kinetics
• red mud
• selective dealkalization

Funding

The authors are thankful for the financial support from the Key Project of Scientific Research in Colleges and Universities from Henan Province (15A440014, 16A530006), the Fundamental Research Funds for the Universities of Henan Province (NSFRF140112), and the Doctoral Foundation from Henan Polytechnic University (B2014-009, B2014-012).

Additional information

Funding

The authors are thankful for the financial support from the Key Project of Scientific Research in Colleges and Universities from Henan Province (15A440014, 16A530006), the Fundamental Research Funds for the Universities of Henan Province (NSFRF140112), and the Doctoral Foundation from Henan Polytechnic University (B2014-009, B2014-012).