11-05 :: May/June 2011

nanotimes News in Brief

MgO Production // A New Method to Recover NH4

M

agnesium chloride is usually generated as byproduct or waste of the potassium fertilizer

industry. The valuable magnesium resources cannot be utilized effectively and is discarded back into the sea or saline lakes, causing a serious environmental problem. Therefore, extraction and application of magnesium resources existing in saline brine is gro- wing interesting from an ecological, economic and technological point of view. An attractive way to be- neficiate magnesium chloride brine is to prepare high quality MgO. However, the tough problem is how to regenerate or recover the valuable byproducts of NH4

Cl. A new method to recover NH4 Cl from NH4 Cl-rich

aqueous solutions in the magnesia (MgO) production is proposed by researchers from the Key Laboratory of Green Process and Engineering of Institute of Process Engineering. In their research, the recover process was constructed by modeling the solid-liquid equilibrium (SLE) for the system of NH4

Cl-MgCl2 -H2

with the Pitzer model embedded in Aspen PlusTM platform. New model parameters were obtained and used to correlate the equilibrium constant for NH4

MgCl3 ·6H2 Cl. The

55

Cl in the Production of MgO

Daoguang Wang and Zhibao Li: Modeling solid–liquid equilibrium of NH4Cl-MgCl2-H2O system and its applica- tion to recovery of NH4Cl in MgO production, In: AIChE Journal, Vol. 57(2011), Issue 6, June 2011, Pages 1595- 1606, DOI:10.1002/aic.12357: http://dx.doi.org/10.1002/aic.12357

Institute of Process Engineering: http://english.ipe.cas.cn/

O

Key Laboratory of Green Process and Engineering, Chinese Academy of Sciences: http://english.ipe.cas.cn/rh/rd/200906/t20090629_9235.html

O, which was found to play a key role in the recovery of NH4Cl. The phase-equilibrium di-

agram generated by modeling is illustrated to identify the process alternatives for recovering NH4

resulting course of three consecutive crystallizations to recover NH4Cl was finally proved feasible.

Image: SEM of ammonium carnallite and ammonium chloride. © WANG Daoguang etc.