ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 6, pp. 860 !863. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + A.I. Nikolaev, V.B. Petrov, Yu.V. Pleshakov, Yu.G. Bychenya, G.I. Kadyrova, 2007, published in Zhurnal Prikladnoi Khimii,
2007, Vol. 80, No. 6, pp. 887!890.
AND INDUSTRIAL INORGANIC CHEMISTRY
Purification of Sphene Concentrate to Remove Phosphorus
Impurity with Dilute Mineral Acids
A. I. Nikolaev, V. B. Petrov, Yu. V. Pleshakov, Yu. G. Bychenya, and G. I. Kadyrova
Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Resources, Kola Scientific Center,
Russian Academy of Sciences, Apatity, Murmansk oblast, Russia
Apatit Open Joint-Stock Company, Apatity, Murmansk oblast, Russia
Received December 26, 2006
Abstract-Methods of crystal-optic, X-ray phase, chemical, and IR spectroscopic analyses were used to
study the interaction of sphene and fluorapatite concentrates with dilute mineral acid solutions. The conditions
under which the sphene concentrate can be purified to remove admixtures of phosphorus-containing com-
pounds were found.
) is a rock-forming mineral
in apatite-nepheline ores of the Khibiny deposits.
The sphene concentrate obtained in dressing of these
ores is regarded as a promising raw material for pro-
duction of titanium pigments and for use in coatings
of welding electrodes . Presence of phosphorus in
the concentrate intended for manufacture of the titani-
um dioxide pigment leads to a pronounced decrease in
the yield of titanium into the final product  and
precludes direct use of the concentrate in coatings of
welding electrodes. According to technical specifica-
tions for the sphene concentrate for welding electrodes
[TU (Technical specification) 1715-069-00 203 9383
2000], the content of phosphorus should not exceed
0.1% in terms of P
. The presence of phosphorus is
due to the fact that the sphene concentrate contains
an admixture of a fluorapatite mineral, Ca
both as aggregations with sphene and separately.
Phosphorus compounds cannot be removed to
the required extent in the dressing stage. Therefore,
chemical purification methods based on decomposi-
tion of fluorapatite with dilute solutions of mineral
acids (sulfuric acid, for the most part) have been sug-
gested . In this process, sphene remains unchanged.
The content of phosphorus in the initial sample of
the sphene concentrate used to develop the purifica-
tion procedure was 1.88% in terms of P
The conditions of the given process require an ad-
ditional study to substantiate the choice of an acid
and minimize its expenditure at satisfactory purifica-
tion parameters. The mineralogical
compositions of the starting sphene and fluorapatite
concentrates used in this study are listed in Tables 1
and 2, respectively.
Chemical purification to remove fluorapatite can be
performed not only with sulfuric acid, but also with
hydrochloric and nitric acids . With H
Table 1. Mineralogical composition of sphene and fluor-
³ Sphene ³ Apatite
³ concentrate ³ concentrate
³ content, wt %
Sphene ³ 86.0 ³ 0.4
Fluorapatite ³ 4.5 ³ 95.1
Nepheline ³ 3.2 ³ 1.8
Aegirine ³ 4.5 ³ 0.8
Feldspars ³ 1.5 ³
Hydromicas ³ 0.5 ³ 0.1
Mineralogical analysis was made by V.F. Fedchenko at
the Central laboratory of Apatit Open Joint-Stock Company.