Strontium aluminate mixed oxide and method for producing same
OwnerThomas Harmening, Marcos Schoneborninventors
Life of this patent
Estimating the term…
Abstract
The invention relates to a strontium aluminate mixed oxide precursor and a method for producing same, as well as to a strontium aluminate mixed oxide and method for producing same. The strontium aluminate mixed oxide precursor can be transformed into a strontium aluminate mixed oxide at relatively low temperature. The strontium aluminate mixed oxide is characterized by substantially spherically-shaped particles with a spongy- or porous bone-like microstructure. A luminescent material including a strontium aluminate mixed oxide is also provided.
Claims17
A method of preparing a strontium aluminate mixed oxide precursor, the method comprising:
- a) according to a first method:
- i) providing a boehmite suspension, wherein the boehmite in the boehmite suspension has a crystallite size (021 and/or 020 reflex) of between 3 nm and 50 nm;
- ii) hydrothermally treating the suspension to obtain a hydrothermally treated boehmite suspension;
- iii) adding a strontium compound to the hydrothermally treated boehmite suspension to form a strontium alumina suspension (Sr—Al suspension);
- and
- iv) drying the Sr—Al suspension to produce the strontium aluminate mixed oxide precursor;
- or
- b) according to a second method:
- i) providing a boehmite suspension, wherein the boehmite in the boehmite suspension has a crystallite size (021 and/or 020 reflex) of between 3 nm and 50 nm;
- ii) adding a strontium compound to the boehmite suspension to form a strontium alumina suspension (Sr—Al suspension);
- iii) hydrothermally treating the Sr—Al suspension to obtain a hydrothermally treated Sr—Al suspension;
- and
- iv) drying the hydrothermally treated Sr—Al suspension to produce the strontium aluminate mixed oxide precursor;
- or
- c) according to a third method:
- i) providing a boehmite suspension, wherein the boehmite in the boehmite suspension has a crystallite size (021 and/or 020 reflex) of between 3 nm and 50 nm;
- ii) hydrothermally treating the suspension to obtain a hydrothermally treated boehmite suspension;
- iii) adding a strontium compound to the hydrothermally treated boehmite suspension to form a strontium alumina suspension (Sr—Al suspension);
- iv) hydrothermally treating the Sr—Al suspension to obtain a hydrothermally treated Sr—Al suspension;
- and
- v) drying the hydrothermally treated Sr—Al suspension to produce the strontium aluminate mixed oxide precursor.
A strontium aluminate mixed oxide, wherein the strontium aluminate mixed oxide has particles with a spongy- or porous bone-like microstructure, which is characterized by being built up from a non-porous primary framework of particles that are interconnected by thin, fragile sinter necks to a three-dimensional secondary structure, with a pronounced macro pore structure, and at least the following properties:
- i) a pore volume of less than 0.05 ml/g for pore radii in the range of from 15 Å to 500 Å, measured by Hg intrusion;
- and
- ii) a pore volume in the range of from 0.7 to 1.5 ml/g for pore radii in the range of from 300 Å to 5000 Å, measured by Hg intrusion.
A method of preparing a strontium aluminate mixed oxide, the method comprising:
- a) according to a first method:
- i) providing a boehmite suspension, wherein the boehmite in the boehmite suspension has a crystallite size (021 and/or 020 reflex) of between 3 nm and 50 nm;
- ii hydrothermally treating the suspension to obtain a hydrothermally treated boehmite suspension;
- adding a strontium compound to the hydrothermally treated boehmite suspension to form a strontium alumina suspension (Sr—Al suspension);
- iv) drying the Sr—Al suspension to produce the strontium aluminate mixed oxide precursor;
- and
- v) calcining the strontium aluminate mixed oxide precursor to produce the strontium aluminate mixed oxide;
- or
- b) according to a second method:
- i) providing a boehmite suspension, wherein the boehmite in the boehmite suspension has a crystallite size (021 and/or 020 reflex) of between 3 nm and 50 nm;
- ii) adding a strontium compound to the boehmite suspension to form a strontium alumina suspension (Sr—Al suspension);
- iii) hydrothermally treating the Sr—Al suspension to obtain a hydrothermally treated Sr—Al suspension;
- and
- iv) drying the hydrothermally treated Sr—Al suspension to produce the strontium aluminate mixed oxide precursor;
- and
- v) calcining the strontium aluminate mixed oxide precursor to produce the strontium aluminate mixed oxide;
- or
- c) according to a third method:
- i) providing a boehmite suspension, wherein the boehmite in the boehmite suspension has a crystallite size (021 and/or 020 reflex) of between 3 nm and 50 nm;
- ii) hydrothermally treating the suspension to obtain a hydrothermally treated boehmite suspension;
- iii) adding a strontium compound to the hydrothermally treated boehmite suspension to form a strontium alumina suspension (Sr—Al suspension);
- iv) hydrothermally treating the Sr—Al suspension to obtain a hydrothermally treated Sr—Al suspension;
- v) drying the hydrothermally treated Sr—Al suspension to produce the strontium aluminate mixed oxide precursor;
- and
- vi) calcining the strontium aluminate mixed oxide precursor to produce the strontium aluminate mixed oxide.
Dependencies are inferred from the claim text.