Year: 1886

page_text: I, HENRY MATHEY, residing at No. 101, Wall Street, in the City of New York,
in the County of New York, and State of New York, in the United States of
America, gentleman, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement:—
My invention relates to improvements in the manufacture of cement from
argillaceous lime stone. These are generally termed natural cement rock for the
reason that when properly burned and calcined, the resulting product will set
under water. Heretofore the natural cement rock after quarrying, undergoes
a practical selection or sorting at the quarry; and the sorted material conveyed to
vertical kilns where it is burnt. Notwithstanding this sorting at the quarry it is
very difficult to obtain an uniform cement rock; & as mistakes occur in the
selection, the resulting cement constantly varies in quality. Moreover it is at
once apparent that the suppose refuse which is thrown aside as waste, often and
usually does contain excellent stone which could be utilized for the manufacture
of cement. It is a well-known fact (as set out by Vicat, Rivot, Reid and Gilmore,)
that the best hydraulic cements owe their high quality of hydraulicity to the
double silicates of lime and alumina formed during the burning.
Natural cement rock in the United States, and I believe in most countries, is
deficient in alumina, and consequently the cement made does not contain enough
double silicates to materially improve its setting quality and its ultimate strength.
In letters patent granted to me the cement rock has been ground previous to
burning. It is apparent that by the old methods of burning in vertical kilns no
alluvial clay could be added to the rock for the reason that it would choke up the
draft.
Moreover, as the rock must be in large pieces in said vertical kilns (to provido
a draft) there could not be that requisite ultimate contact between the clay and
rock during the burning.
Now by my process I take the natural cement rock, crush it to a uniform degree
of fineness, say to a fineness that will pass through a number, 4, to, 8, mesh screen,
or a screen having, 16, or, 64, openings to the square inch. Now I propose by
my present process to treat natural or ordinary cement rock in the same way as in
the manufacture of Portland Cement. Therefore, instead of lime stone and clay,

page_text: I propose to use natural cement rock and clay, and to accomplish this purpose
I proceed as follows. The natural cement rock after being crushed as described, is
analyzed to ascertain its exact composition. I then add the necessary amount of
clay for the formation of the double silicates during the operation of calcination.
After the clay is thoroughly dried it is crushed to the fineness of the stone and
then added to the rock, and their ultimate mixture is made by means of proper
apparatus for the purpose. This mixture is then fed into a revolving cylinder.
The cement obtained has been found by experiment to be quick setting, and to
possess great strength and tenacity. It is also well-known that many quarries of
lime stone have been abandoned because the stone when burned does not possess
hydraulicity, owing to a deficiency in silica. In my process by adding the clay,
I also bring in this element, (silica,) which is the most active and necessary element
in the formation of silicates of lime and alumina. In most countries excellent
clays are found which show by analysis about, 80% of silica and alumina; the
proportion being about, 56% of silica to 25% of alumina. Therefore it will be
Been that by the addition of clay to the cement rock before burning, we obtain all
the elements necessary to the formation of perfect hydraulic cement. Again by
this process dolomite or deposits of magnesian lime stone can also be made available
and produce an excellent cement. Clay is much cheaper to obtain and easier to
handle than rock; hence I obtain by my process an element which not only
increases the quantity of cement for a given amount of stone, but also greatly
decreases the cost of manufacturo.
Having now particularly described and ascertained the nature of my said
invention, & in what manner the same is to be performed, I declare that what
I claim is,―
The process of manufacturing hydraulic cement which consists in first crushing
the natural cement rock to a suitable degree of fineness, then adding to this raw
material alumina and silica in the form of alluvial clay, next mixing together these
elements and finally burning them under agitation, to form the double silicates of
lime and alumina.
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