Year: 1885

page_text: I HENRY MATHEY, residing at 101, Wall Street, in the City of New York,
County 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 the manufacture of Portland Cement, lime and Plaster-
Paris.
Portland cements are usually made by mixing the different elements in their
proper proportions, (such as lime, alumina and silica,) into a pasty mass or "slip."
This mass is subsequently made into bricks, which require to be dried either
naturally or artificially, after having become thoroughly dried the bricks are
burned in a Portland Cement kiln, and after calcination the residual product is
pulverized.
This method of burning permits the admixture of ashes with the cement, and
this is an element of weakness.
Moreover this method of making the cement is expensive by reason of the
various handling and labor required.
There is also great irregularity in the burning, as the center of the bricks are
under-burned while the outside has passed the stage of incipient vitrification.
I now propose to do away with the formation of the bricks and admixture of
ashes as just described.
To attain this I take the proper proportions of the several elements entering
into Portland Cement and grind them together into a fine powder, this powder is
then fed into a heated receptacle which is kept constantly moving so as to agitate
and disseminate the particles and thereby often expose their surfaces to the action
of the heat.
It is apparent that this action causes the particles to be uniformly exposed to the
heat and regularly burned.
Again, as the receptacle can be heated as desired there is no opportunity afforded
for "slagging" the material,-nor will there be any overburnt and underburnt
portions.

page_text: Plaster of Paris or Gypsum is prepared and burned in the same manner.-
Instead of first drying the gypsum in ovens to dehydrate it, the gypsum is first
ground to a fine powder and then calcined as just described without any subsequent
pulverization.
'
For the manufacture of ordinary lime, the rock is first crushed so as to preferably
pass through a No. 4, or, No. 6, mesh screen, and is then conveyed directly to the
heated and moving receptacle where it is burned.
By this process of preparing the elements previous to the burning and in the
subsequent burning I am enabled to obtain a product which is constant and uniform
in quality.
Moreover as there is no mixture of ashes or other impurities arising from the
calcination, there is a freedom of these elements of weakness.
Again there is a great reduction in the cost of producing the articles of commerce
just described, for the labor of successive and expensive handling is dispensed with.
It is also apparent that the time required for burning is greatly reduced.
For as the material is in a very fine state and in a state of motion or suspension
the contained water and gases to be dispelled, are much more rapidly driven off
than if the particles were large and kept in a comparatively passive or quiescent
state as in a vertical or ordinary kiln.
By this process I am enabled to obtain a high grade of cement, plaster of Paris
and lime in a burning, ranging from thirty to ninety minutes.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1st. In the process of manufacturing hydraulic cement or plaster of Paris which
consists in first pulverizing the materials to be burned to a fine powder and then
calcining said materials while in a condition of agitation or movement and in a
state of dissemination.
2nd. The process of manufacturing lime which consists in first crushing the rock
to a suitable degree of fineness and then burning this crushed material while in a
condition of agitation or movement and in a state of dissemination.
Dated : AL
CAT
L. 10OK