The Synthesis of Crystalline Rare Earth Carbonates

Abstract

The factors which influence the crystallization of rare earth carbonates were studied. Crystalline rare earth carbonates were precipitated at various temperatures from aqueous solutions by using sodium carbonate, sodium bicarbonate, trichloroacetic acid, and urea as precipitants. The crystal parameters, compositions, and factors concerning the formations of various carbonates, such as lanthanite-type Ln2(CO3)3·8H2O(Ln=La, Ce), tengeritetype Ln2(CO3)3·nH2O(Ln=Nd, Sm, Gd, Dy, Ho, Er, and Y, n=2–3), monoxocarbonate-type Ln2O(CO3)2·nH2O(Ln=La, Ce, Nd, and Sm, n=1–2) and a hydrated double carbonate of rare earth and sodium (rare earth= La, Ce, Nd, Sm, Gd, Dy, and Y) were determined by chemical analysis and X-ray powder diffractometry.

Synthesis, characterization and formation mechanism of dumbbell-like YOHCO3 and rod-like Y2(CO3)3·2.5H2O

“…However, their particle shapes are reported to be irregular. The factors that influence the crystallization of rare-earth carbonates have been reported by Nagashima et al [26].…”

Experimental study of rare earth element partitioning between calcite and sodium chloride solution at room temperature and pressure

“…Tanaka et al (2004) showed that the partition coefficients of La, Ce and Pr using lower REE concentration solutions (e.g., 1 ppb) are smaller than those of the higher REE concentrations (10 to 100 ppb), but HREE partition coefficients for low and high concentration cases are similar. They pointed out that these observations might be related to the difference between light and heavy REE in the syntheses of crystalline REE carbonates reported in Nagashima et al (1973) A-2 Shannon (1976).…”

Experimental REE partitioning between calcite and aqueous solution at 25.DEG.C. and 1atm: Constraints on the incorporation of seawater REE into seamount-type limestones

“…Alternatively the light REEs may have precipitated partly as REE carbonate like REE 2 (CO 3 ) 3 , not as NaREE(CO 3 ) 2 . Nagashima et al (1973) reported the synthesis of crystalline REE carbonates from REECl 3 solutions by addition of NaHCO 3 or Na 2 CO 3 : At 20°C and 1 atm, lanthanite-type carbonates [REE 2 (CO 3 ) 3 ·8H 2 O] precipitated in the La and Ce solutions, whereas NaREE(CO 3 ) 2 ·nH 2 O precipitated in the other REE solutions. From the plots of Fig.…”