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10
Keramický zpravodaj 27 (2) (2011)
NATRON
Davidovits [3] presents several methods of the preparation
of agglomerated stones. One of them is optimistic, where
it requires only 5 kg of natron and 10kg of lime as neces-
sary to cast 1 t of stone. When the whole pyramid inclu-
des 6,500,000 t of geopolymeric limestone, then 32,400 t
of natron would be necessary. Davidovits’ public experi-
ments with the production of artificial stone were linked
to with much higher concentrations of natron. Therefore,
during one year, at least 1,600 t of natron would be tran-
sported from a 70 km distance for the purpose of pyramid
construction. Transport of such quantities would be unrea-
listic if this material were pure natron (Na
2
CO
3
.10H
2
O), as
it would melt in its crystalline water in the hot climate
existing in Egypt. Only the transport of crystallised salts
could be considered.
Davidovits reports natron composition as pure Na
2
CO
3
,
which is impossible according to available materials.
At present, Na
2
CO
3
is produced from trona
(Na
2
CO
3
.NaHCO
3
.2H
2
O) e.g. at Lake Magadi (Kenya).
ASH-LIME
I also tried to calculate whether all the straw produced in
Egypt would suffice for the annual production of calcium
hydrate for the construction of the Pyramid of Cheops.
First, the fertile land of Ancient Egypt was concentrated
along the Nile River (river length = 2,000 km). Later, after
a system of channels had been built, it also extended
inland. During the 3
rd
dynasty, the area amounted to
6 million aureas, which equals 1,650,000 ha (10 aureas =
2.75 ha). As far as cereals are concerned, particularly bar-
ley was grown (the six-row type, particularly for beer pro-
duction) and wheat (einkorn, two-grain, and spalt).
For the calculation of crop yield,
1
/
4
of the actual crop yield
values in the Czech Republic (2006) [11] is considered.
Barley straw contains 0.0354 % Ca [12], and let us suppo-
se that this content will be identical also in wheat. Calci-
um (Ca) production per year would be 1,432.33 t of Ca.
In 20 years in the same conditions 28,646.6 t of Ca would
be produced, which equals 80,922,600 t of straw. The
construction of a geopolymeric pyramid would require
45,454.9t of lime. The quantity of lime produced by bur-
ning straw would therefore not be sufficient in existing
conditions and on the assumption of one crop per year. In
addition to that, the calculation is based on the (false) pre-
condition, that crops were good in each of the years.
Another considered source could be wood ash [13]. Wood
ash contains a significantly higher calcium content of 7 –
33 %, and 5 - 30 % of carbon, 1 – 2 % of magnesium,
0.3 – 1.3 % of manganese, 0.3 – 1.4 % of phosphorus,
and 0.2 – 0.5 % of sodium. From the point of view of cal-
cium content, wood is a more suitable source of calcium
than straw. Therefore, for the production of 65,000 t of
lime, one would burn 154,849.67 t of wood (33 % Ca
content considered) over 20 years, i.e. 7,742.48 t per year.
X-RAY ANALYSIS OF THE KHUFU’S PYRAMID CASING
Limestone from the casing of Khufu’s Pyramid is a type of
yellowish limestone of very good quality – fine to very fine
crystalline limestone of the nummulite type from the
Mokattam Mountains [14].
Fig. 12 shows X-ray diffraction patterns of part of the
Cheops Pyramid casing and its insoluble residue after acid
leaching. It can be seen from Fig. 12 that the material is
very pure limestone with ankerite (98 %), with quartz as
a minor component (Fig. 6a).
It follows from Fig. 6 that it is very pure limestone
with ankerite (98 %) with quartz as a minor component
(Fig. 6a). The probable composition of ankerite is
Ca
.997
Mg
.273
Fe
. 677
Mn
0.54
(CO
3
)
2
.
Fig.6
Sample of limestone from the Cheops Pyramid casing (a) and its insoluble residue after acid leaching (b). Cal – calcite,
Ank – ankerite, Q – quartz, G – gypsum, Pal – palygorskite, K-fel – (very probably microcline), Gt-goethite.
CZ 2006
wheat yield
4.89 t/ha
barley yield
4.05 t/ha
Egypt
wheat yield
1.22 t/ha
2,013,000 t/year
barley yield
1.01 t/ha
2,033,130 t/year
Tab. 2
Crop yield for he calculation