SPECTROPHOTOMETRIC DETERMINATION OF NIOBIUM IN CARBONATITES

Journal Article · Sun Jan 01 04:00:00 EST 1961 · Issledovatel. Inst. Geol. Arktiki, Ministerstva Geol. i Ikhrany Nedr S.S.S.R.

OSTI ID:4763399

Epshtein, R Ya; Ginberg, G P; Nauch, T

The determination of Nb in carbonatites having a predominant content of calcite, as well as a high P-content, requires decomposition of the sample in acetic acid. The insoluble, Nb-containing residue is dissolved and the spectrophotometric determination performed by using NH/sub 4/SCN as agent. 0.4 g of the rock is heated for 1 hr with 20 ml of 25% acetic acid on a water bath with stirring. The insoluble residue is filtered off, and washed out with 0.5% acetic acid. Filter plus residue are incinerated in a quartz crucible, and the ashes are fused with 1.25--2.5 g Na/sub 2/S/sub 2/O/sub 7/ or K/sub 2/S/sub 2/O/sub 7/. The melt is dissolved in 12.5--25 ml tartaric acid (15%), the residue filtered off, and the filtrate is diluted with water to 25 or 50 ml. Five ml of a 10% solution of SnCl/sub 2/ in concentrated HCl and 15 ml of a freshly prepared mixture of 23% solution of NH/sub 4/SCN with acetone (1:2) are added to 5 ml of the resulting solution. The spectrophotometric determination follows after a period of 30--40 min by using a spectrophotometer at 405 m mu in 1 cm cells, employing the solution of a control test for purposes of comparison. The color is stable for a period of 5 hr. A calibration curve is plotted by using a standard solution of Nb-tartrate + 100 gamma /ml of Nb/sub 2/O/sub 3/. The analysis takes half the time of that with tannic acid. (Referativnyy Zhurnal, Khimiya, No. 19, 1961.)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-16-031575
• OSTI ID: 4763399
• Journal Information: Issledovatel. Inst. Geol. Arktiki, Ministerstva Geol. i Ikhrany Nedr S.S.S.R., Journal Name: Issledovatel. Inst. Geol. Arktiki, Ministerstva Geol. i Ikhrany Nedr S.S.S.R. Vol. Vol: 119
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ACETIC ACID
ACETONE
AMMONIUM COMPOUNDS
CALCIUM CARBONATES
CARBONATITES
CHEMISTRY
COMBUSTION
CYANIDES
DECOMPOSITION
DIAGRAMS
FUSED SALTS
HYDROCHLORIC ACID
NIOBIUM
ORGANIC SULFUR COMPOUNDS
PHOSPHATES
PHOTOMETRY
POTASSIUM SULFATES
PYROSULFATES
QUANTITATIVE ANALYSIS
RESIDUES
SOLUTIONS
SPECTROSCOPY
STANDARDS
TARTARIC ACID
TIN CHLORIDES