Prezentace aplikace PowerPoint

1
New glass ceramic fertilizer based on
K2O-CaO-MgO-P2O5
Martin Maryka, Zdenka Patocková Institute of
Chemical Technology Prague, Department of Glass
and Ceramics 166 28 Prague 6, Czech Republic,
tel. [phone], fax. [phone]
00 E-mail Martin.Maryska_at_vscht.cz,
Zdenka.Patockova_at_vscht.cz

Introduction
Experimental
Tab.1 Chemical composition of the material
The protection of environment is very important
in industry world. A new glass-ceramic material
based on K2O-CaO-MgO-P2O5 can be used as modern
fertilizer for feeding of plants. Its properties
and composition supports a grow of plants, but it
must be used only in amount, which is needed and
which is not dangerous for environment.
It was found, that plants need for their grow
only some elements. It was prepared a new
material from this elements. Its chemical
composition is shown in table 1.
These methods were used for identification of
prepared material differential thermal analysis
(DTA) and x-ray diffraction. It was identified
this material is created from crystals where can
be in 3 crystallographic modifications (?, ?, ?).
DTA diagram is shown in figure 1.
Methods

• Differential thermo analysis.
• rtg. phase analysis.
• Potentiometer measuring of pH.
• Atomic absorption spectrometry
• Colorimetry.
• REM EDS

Fig. 1 DTA curve of prepared K2CaMg(PO4)2
The separate crystallographic phases were
prepared from the original material by heating to
the temperature of phase change the temperatures
of transitions from ? to ? and from ? to ? are
820C and 1060C, respectively and time of the
tempering was 2 hours. The samples were quickly
quenched in liquid nitrogen after this
operation. The rtg. diffractograms are shown in
figure 2
Conditions

• Accurate weight of particles of size
  0.160.315 mm.
• Distilled water as corrosive solution (80 ml).
• The ratio S/V 0.1 cm-1 is constant.
• The temperatures - 4, 37, 220C.
• The time from 2 to 72 hours.
• Static conditions.

Fig. 2 The rtg. diffractograms of K2CaMg(PO4)2

Results
Dependence of concentrations of K and PO43- and
pH on time
Dependence of concentrations of Ca2 and Mg2 and
pH on time
Next graphs (1, 2) shows some results of chemical
analysis of solution after leaching of the ?
samples by the temperature 220C. The dissolution
of material is congruent and therefore all
results are not presented.
Analysis of secondary solid state after leaching
? - phase by the temperature 220C
Graph 1 Leached amount of K and PO43-, 220C
Graph 2 Leached amount of Ca2 and Mg2, 220C
Conclusions
References
1. The material can be prepared in 3
crystallographic modifications with different
solubility. The gamma phase is most dissoluble in
water solutions.

• C. F. Drake
• Vitreous controlled release fertilizer
  composition
• U. K. Patent no. 1512637.10
• C. F. Drake, M. Tripp
• Glass composition
• U. K. patent no. 2037735B

2. By selection of modification and/or grain size
can be controlled velocity of dissolution.
3. It is not determined the mechanism of solution
by the temperatures 4 and 37C (solution is too
slow).
This work was supported by GACR (Grant no.
106991419 and no. 103000957)
4. The secondary crystal phase deposits on the
original material during solution.
5. It seems dissolution of phases is congruent.