Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 11, pp. 1662−1666.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © E.P. Lokshin, V.N. Lebedev, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 11, pp. 1751−1755.
AND INDUSTRIAL INORGANIC CHEMISTRY
Processing of Cakes Based on Sodium Metazirconate
E. P. Lokshin and V. N. Lebedev
Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral
Raw Materials, Kola Scientiﬁ c Center, Russian Academy of Sciences, Apatity, Russia
Received May 12, 2012
Abstract—Certain methods of processing cakes based on sodium metazirconate and obtained by the reaction of
a baddeleyite concentrate with sodium nitrate or nitrite were studied. Conditions were found for the synthesis of
strontium metazirconate and also of nanosized powders of basic zirconium sulfate, which is promising as a com-
ponent of polishing mixtures.
Cakes based on sodium metazirconate Na
2] can be obtained by the heat treatment of mixtures of
baddeleyite with sodium compounds (Na
, and NaNO
). Zirconium is taken from cakes to
a solution by dissolving sodium zirconate in acids. After
that zirconium can be isolated and reﬁ ned by the extrac-
tion from nitrate media or precipitated as oxychloride or
basic sulfate from hydrochloric media.
The aim of this work was to study methods of obtain-
ing certain zirconium products from solutions prepared
by acid leaching of cakes based on sodium metazirconate
derived by the reaction of a baddeleyite concentrate (BC)
with sodium nitrate or nitrite .
One of widespread procedures for isolating and re-
ﬁ ning zirconium is the precipitation of basic zirconium
sulfate (BZS) from hydrochloric or nitrate acid solu-
tions. The process has been sufﬁ ciently studied [3–7].
The precipitation is carried out at the molar ratio ZrО
= 1 : (0.4–0.75), preferentially 1 : 0.65, temperature
100–105°С, and acidity 10–15 g l
of hydrochloric or
nitric acid. Acidity reduction promotes the precipitation
completeness, but in this case the puriﬁ cation efﬁ ciency
decreases. At the minimal molar ratio particle size of
BZS decreases and the ﬁ ltering worsens, and at the
maximal, solubility of BZS increases. The composition
of precipitates varies from 5ZrО
О up to
О depending on the molar ratios . The
precipitation of BZS is possible directly from solutions
obtained by caking of BC with an alkali or sodium ni-
trate in contrast to the procedure of caking with calcium
oxide, in which calcium sulfate will be coprecipitated on
introduction of sulfate ions.
Solutions obtained by leaching sodium zirconate under
the action of 10 wt % HCl were neutralized by sodium
carbonate up to the free acid content of 10 g·l
, then am-
monium sulfate was added up to a necessary ZrО
molar ratio, and the mixture was subjected to a hydrolysis
within 1 h at 100°С. The resulting pulp was settled; the
precipitate was washed out on a ﬁ lter with water and
ﬁ ltered. The experimental results are given in Table 1.
It was found in BZS (wt % in relation to ZrО
CaO 0.01–0.03, Fe
0.18–0.22, and Nb
0.41–0.49. Contents of these
components in BZS depend only slightly on the amount
of added sulfate ions. Titanium and niobium, which also
form basic sulfates, are precipitated almost completely.
Radioactivity of puriﬁ ed baddeleyite concentrate is de-
ﬁ ned by U
, which is not inclined to form binary sul-
fates, therefore radionuclides are removed by more than