Note: Descriptions are shown in the official language in which they were submitted.
13~0~3
New reactive derivative of zirconium and its
preparation
The invention relates to a new reactive deriva-
tive of zirconium and to its preparation.
The term "reactive derivative of zirconium" de-
notes a zirconium compound which is in solution in an
aqueous or organic solvent or can be dissolved in such
a solvent. The reactive derivative of zirconium can
react in the dissolved stste with other compounds.
Many reactive derivatives of zirconium are
known. Among these, those most commonly employed in in-
dustry are the following:
basic zirconium csrbonate (C02/ZrO2 ~ 0.5) con-
taining 40% by weight of ZrO2, in the form of moist
paste,
zirconium orthosulphate (sulphate/ZrO2 ~ 2)
either in the form of aqueous solution (containing 18%
by weight of ZrO2), or in the form of crystallized
solid (containing 32% by weight of ZrO2),
zirconium oxychloride (chloride/ZrO2 ~ 2~
either in the form of aqueous solution (containing 20%
by weight of ZrO2) or in the form of crystallized solid
(cont~ining 33% by weight of ZrO2),
ba ic zirconium sulphate (sulphate/ZrO2 ~ 0.6
to 1) in the form of moist paste (containing 37% by
weight of ZrO2),
zirconium nitrate in the form of aqueous solu-
tion (containing 19% by weight of ZrO2) or of solid
~containing 40% by weight of ZrO2),
zirconium acetate in solution (containing 22
by weight of ZrO2),
zirconium hydroxide (containing 42% by weight
of ZrO2), and
zirconium ammonium carbonate in solution (con-
taining 13% by weight of ZrO2).
Many organic derivatives of zirconium are also
known (propionate, lactate, acetylacetonate, various
alcoholates), whose ZrO2 content ranges from 6 to 15
*
- 2 - 13~ 0 0 ~ 3
by weight.
These materials are employed as such (in the
case of derivatives in ~olution) or must be di~601ved
by reaction with a solution, generally acidic, by the
final u6er ~in the ca~e of derivative~ which are solid
or in paste form).
In practice, only the zirconium present in the
abovementioned materials is generally utilized, and not
the anions (for example chloride, carbonate, sulphate,
nitrate or acetate) and/or the water, even though they
form the greater part of these materials, their role
being essentially to keep the zirconium in a soluble
form. The anions and/or the water do not directly
participate in the reaction~ involved in the practical
applications of these materials and are, in fact,
rather detrimental. In fact, solutions of zirconium
compounds are corrosive and toxic, and this presents
problems in storage and in transport, and pastes based
on zirconium compounds are heterogeneous because of the
presence of free water and are difficult to handle.
Furthermore, certain anions ~particularly ~ulphates and
chlorides) or water can oppose the required reactions,
for example during the production of driers of the zir-
conium soap type. Finally, from an economic ~t~n~roint,
it is not very advantageous to transport materials con-
taining relatively little active material (ZrO2) and to
have to employ costly containers capable of resisting
corrosion, in the case of materials in the form of
solutions or of pastes.
It is therefore advantageous to be able to have
available reactive derivatives of zirconium with a high
Zr~2 content, which are solid materials containing a
minimum of impurities and of water.
The objective of the invention is to provide
such reactive derivatives of zirconium.
More particularly, the invention relates to re-
active derivatives of zirconium, characterized in that
they are in the form of a pulverulent white solid which
is not crystallized and dry in appearance, soluble in
~ 3 ~ 13400~3
an aqueou~ solution of an acid, and consist of
metazirconic acid ZrO(OH)2 accompanied by free or
weakly bound water, it being possible for some of the
OH ions to be replaced by halide ions, the ZrO2
content of the~e derivatives being from 60 to 92% by
weight inclusive, preferably from 75 to 86,5~ by weight,
and the water content of these derivatives ranging from
3 to 40%, preferably 13 to 25%, and the halide ion
content of these derivatives being capable of ranging
up to approximately 5%.
The derivatives of the invention usually con-
tain traces of halide ions originating from impurities
present in the raw materials. However, in the present
description it is considered that the derivatives of
the invention are free from halides when their halogen
content is below 0.02% by weight within analytical
accuracy. A class of preferred derivatives is that of
the derivatives containing, on a weight basis, ~5 to
86.5%of ZrO2, 13 to 25% of water and not more than
approximately 0.5~ of halide ions, in particular Cl-
ions. Another class of preferred derivatives is that of
the derivatives containing, on a weight basis, less
than 13% of water and more than 0.5% of halide ion~, in
particular Cl- ions.
The invention also relates to a process for the
preparation of the abovementioned reactive derivatives
of zirconium, characterized in that it comprises the
steps consisting in:
a) preparing water-rich zirconia hydrate
ZrO2.2H2O or zirconium hydroxide Zr(OH~4,
b) optionally, replacing some of the OH- ions
in the product of step (a) with halide ions, and
c) partially dehydrating, in a controlled man-
ner, the product of step (a) or (b) by heating to a
temperature of not more than 130~C until a pul~erulent
white solid is obtained, which is not crystallized and
dry in appearance and soluble in an aqueous solution of
an acid.
The first step (a) consists in preparing
- 4 ~ 0~3
water-rich zirconia hydrate ZrO2.2H20, al80 called
zirconium hydroxide Zr(OH)4. ~Water-rich~ means a
product contAining at least 45% by weight of water in
total (free water + bound water). Thi~ step may be
performed in various way~, ~uch as, for example:
- Neutr~lization of an acidic aqueous solution of a Zr
~alt (for example the oxychloride, nitrate or acetate),
with a base (for example sodium hydroxide, aqueous
ammonia), followed by filtration and wa~hing of the
filter cake. A bulky and water-rich (gO~ and more) pre-
cipitate of zirconia hydrate or zirconium hydroxide i~
thus obtained.
This method offers the advanta~e of providing a
pure product freed from the impurities which may be
present in the startinq salt.
- Hydrolysis of an organic zirconium salt in solution
in water or a water-alcohol mixture, followed by fil-
tration and washing of the filter cake. However, thi~
method is not advantageous from an economic stand-
point, because an organic Zr salt must be available.
- Displacement of ions from a solid basic Zr salt with
a reactant in aqueous solution or water, dep~n~ing on
circumstances, followed by filtration and washings of
the filter cake. A ~'basic" Zr sulphate (reactant: base
in aqueous solution) or an alkali metal zirconate such
as sodium zirconate (reactant: water) may be employed,
for example, as a basic Zr ~alt. This method is the
preferred method from the point of view of cost. It
also makes it pos~ible to obtain a reactive derivative
of zirconium with a reduced content of free or weakly
bound water. It has the possible disadvantage of leav-
ing fairly high residual contents of sulphates in the
final product, (in the ca~e of a basic Zr sulphate) or
of alkali metal oxides (in the case of an alkali metal
zirconate). However, when the optional step ~b) is
used, the alkali metal oxides are found to be practi-
cally eliminated.
The optional step ~b) of partial substitution
of the OH- ions in the product of step ~a) by halide
i ~
13400~3
s
ion~ makes it possible to obtain reactive derivatives
of zirconium with higher ZrO2 contents. This step,
which i~ used when a halide ion content above 0.02% i~
de~ired, may be conducted by washing the product of
S step (a) with an aqueous solution of the corresponding
hydrohalogenic acid. In the case of washing with hydro-
chloric acid which is intended to substitute Cl- ions
for OH- ions, a Cl- ion content of the order of 5% by
weight can be attained, but the final content can be
ad~usted by carrying out a second washing with the aid
of aqueous ammonia, for example. In the case where the
product of step (a) has been obtained by displacement
of ions from an alkali metal zirconate, such as Na
zirconate, the ~ub~titution of OH- ions by halide ions,
for example Cl-, can be carried out by wsshing the
product of step (a) with an aqueous solution of
ammonium halide, for example ammonium chloride,
optionally acidified with hydrochloric acid. The
residual sodium is thus displaced with a controllable
quantity of Cl by adjusting the pH of the washing
solution. A subsequent w~shing with another acid allows
the corresponding anions to be fixed, even if the
latter do not contribute to the stability (in the case
of washing with HN03 in example 5).
The controlled dehydration step (c) may also be
performed in various ways. This dehydration may be car-
ried out merely by heating the product of step (a) or
(b) in an oven at a temperature not exceeding 120~C in
the case of a nonhalogenated product and not exceeAing
130~C in the case of a halogenated product (that is to
say one in which halide ions have been substituted for
some of the OH- ions)~ in the case of a relative
atmospheric humidity of 50 to 70%. The dehydration
begins already at 30~C but is slow at this temperature.
The operation will be preferably carried out between 80
and 110~C. The degree of dehydration obtAine~ will
obviously vary with the temperature employed and the
degree of heating. The dehydration can also be per-
formed by heating using microwaves. This heating method
- 6 - ~3~00~
is highly effective and rapid. An excessively severe
heating, which would result in the decomposition of
ZrO(OH)2 with production of insoluble zirconia (that i~
to nay of crystallized zirconia) and water, must be
avoided in any case.
The reactive derivatives of zirconium of the
invention can be easily converted into the usual reac-
tive derivatives of zirconium. It suffices to dissolve
the derivatives of the invention in an aqueous solution
of an acid, for example of hydrochloric acid to obtain
zirconium oxychloride, of nitric acid to obtain
zirconium nitrate, and so on. The high solubility of
the derivatives of the invention can be attributed to
the pre6ence of zirconyl ions ZrO2+.
The reactive derivatives of zirconium of the
invention are remarkably stable. After a period of 15
days at 80~C, their solubility in a hydrochloric acid
solution remains higher than 95%, whereas it is then
only 50% in theicase of basic zirconium carbonate.
Depe~ing on their purity, the derivatives of
the invention can be employed as a source of Zr in
various industrial applications. By way of indication,
there may be mentioned:
- the treatment of TiO2-based pigments, the derivative
of the invention being dissolved in situ in a hydro-
chloric or sulphuric medium,
- the treatment of petroleum formations, it being pos-
sible for the derivative of the invention to be dis-
solved on Si~ in hydrochloric acid.
The following examples, which do not imply any
limitation, are given for --------- illustrating the
invention.
Example 1
55 parts by weight of zirconia ~natural oxide
known as baddeleyite or thermal oxide) wi~h an ave-age ~r-
ticle size of 0.6 to 15 ~m are mixed with 45 parts by
weight of NaOH in the form of solid pellets or of con-
centrated aqueous solution. The mixture is heated to
850~C for 1 hour to obtain, after cooling, a solid mix-
_ 7 _ l~n~
ture of sodium zirconate and excess sodiu~ hydroxide.
This mixture is brought into contact with water at
60~C, with stirring (water/mixture weight ratio:
2.5/1). The suspension obtained is filtered and the
filtration residue is then washed in a stream of water
(water/product weight ratio: 20/1). The product ob-
t~ine~ is washed with a 0.lN aqueou~ ~olution of HCl
(solution/product weight ratio: 30/1), and then with
water ~water/product weight ratio: 5/1). The moist
paste obtained i8 then dehydrated for 24 hours at 40~C
at 50-70% relative humidity. The pulverulent solid pro-
duct finally obtained contains, on a weight basis,
approximately 75% of ZrO2, 20% of H20, 5% of Cl and
les~ than 0.5% of various impurities.
Example 2
The operating procedure of example 1 is repea-
ted as far as the first washing of the filtration resi-
due with water, inclusive. The product obtained is then
washed with a concentrated (100 g~l) solution of ammo-
nium chloride (NH4Cl solution/product weight ratio:
3/1) and then with water (water/product weight ratio:
5/1). The resulting product is then dehydrated by heat-
ing to 80~C for 6 hours at 50-70% relative humidity.
The pulverulent solid product finally obtained con-
tains, on a weight basis, 84% of ZrO2, 15% of H20, 0.5~
of Cl- and approximately 0.5% of impurities (mainly
Na20 ) .
Example 3
The operating procedure of example 1 is repea-
ted as far as the first washing of the filtration resi-
due with water, inclusiv~. The product is then dehydra-
ted at 80~C for 12 hour~ at 50-70% relative humidity.
The pulverulent solid product finally obtained con-
tains, on a weight basis, 82% of ZrO2, 13% of H20 and
5% of Cl- and less than 0.5% of impurities (mainly
Na20 ) .
- 8 - 13~0~3
Example 4
1 kg of basic zirconium sulphate, obtained as
described by F. ~arnworth, S.L. Jones, I. ~cAlpine,
"The production, properties and use of zirconium
chemicals", Special Publication of the Royal Soc. of
Chemistry, No. 40, p. 259 ~1981), is suspended in 9
litres of O.lN aqueous ammonia solution. The pH of the
mixture obtained is approximately 7. After stirring at
25~C the product is filtered and the filter cake i~
washed ~ith 5 litres of water. The product obtained is
then dried at 80~C for 12 hours at 50-10% relative
humidity. The solid product finally obtained contains,
on a weight basis, 82% of ZrO2, 13% of H2O and 5% of
impurities (mainly sulphate ions). It should be noted
that the aqueous ammonia could be replaced with another
base.
Example 5
The operating procedure of example 1 is repea-
ted as far as the first washing of the filtration resi-
due with water, inclusive. The product obtained is
washed with a O.lN aqueous solution of nitric acid
(acid solution/product weight ratio: 30/1). The product
is then dehydrated at 80~C for 12 hours at 50-70% rela-
tive humidity. The pulverulent solid product finally
obtained contains, on a weight basis, 82% of ZrO2, 13%
of H20 and 5% of impurities (mainly nitrate ions).
Example 6
The operating procedure of example 1 is repea-
ted as far as the washing with hydrochloric acid, inc-
lusive. The product is then dehydrated at 120~C for 12
hours at 50-70% relative humidity. The pulverulent
solid product finally obtained contains, on a weight
basis, approximately 92% of ZrO2, 3% of H2O, 5% of Cl-
and less than 0.5% of Lmpurities.
Example 7 Preparation o~ a zirconium oxychloride solu-
tion containing 20~ of ZrO2
The product of example 2 is added to a 37%
strength aqueous solution of hydrochloric acid in such
quantities that the molar ratio Cl/ZrO2 i5 equal to
134~ 3
g
approximately 2; the whole is heated to 100~C for 30
minutes and water is then added to ad~ust the relative
density of the resulting solution to 1.37, and the lat-
ter i8 then cooled to ambient temperature.
Example 8 Preparation of a zirconium nitrate solution
contain~ng 20% of Z~~2
The product of example 2 is added to a 65~
strength aqueous solution of nitric acid in such quan-
tities that the molar ratio N03/ZrO2 is equal to appro-
ximately 2 and that the proportion of ZrO2 i8 approxi-
mately 20~ by weight. The whole is heated to 80~C for 1
hour and is then cooled to ambient temperature.
It is self-evident that the embodiments des-
cribed are merely examples and that they could be modi-
fied, particularly by the substitution of technicalequivalents, without thereby departing from the scope
of the invention.
