US1332422A - Process for the manufacture of cements and similar products - Google Patents

Description

M. L. BOILLOT AND J. DAUDIGNAC.

PROCESS FOR THE MANUFACTURE OF CEMENTS AND SIMILARPHODUCTS.

APPLICATION FILED JUNE 28. 91s.

1 ,332,4;22 Patented Mar. 2, 1920.

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STATES PATENT OFFICE.

MAURICE LUCIEN BOILLO'I AND JEAN DAUZDIGNAC, OF MOU'IIERS, FRANCE.

PROCESS FOR THE MANUFACTURE OF CEMENTS AND SIMILAR PRODUCTS.

AppIication filed June 28, 1918.

ent elements of the said products, to whatever combination they belong.

It is universally admitted and recognized in the present manufacture that the temperature in the interior of the burning kiln must not reach such a degree that the materials introduced into the same should fuse, and in all kilns hitherto used, even in the most modernones, regulation of the said temperature is exceedingly difiicult, and it is necessary to stop the operation at the beginnin of vitrification of the materials used. This results in the serious drawback that, after each taking out of the kiln, there is obtained a large quantity of unhurnt material owing to inequalities of temperature in the various zones of the kiln. Moreover, there is a risk of the vitrified materials adhering to the walls of the kiln, as the latter cannot provide the temperature required to keep the melted materials in a liquid state,

or enable a complete homogeneity of the product to be insured.

The electri furnace already commonly used in electro-chemistry and electro-metallurgy, is remarkable by the flexibility of its working; it makes it possible to obtain any temperature,from a few hundreds of degrees to that of the volatilization of coal, with the possibility of modifying its Work.-

in at any moment or bringing it to the most suitable temperature for the manufacture in question.

In the process according to this invention, the constituent materials of the cement are first ground, then thoroughly mixed together Without a previous treatment,

introduced into the-electric furnaoe wher e they are completely melted. I Owing to the considerable temperature obtained, the materials completely react on each other in order to form calcic silicates and aluminates,

Specification of Letters Patent.

Patented Mar, 2, 1920,

Serial No. 242,422.

and transmit by radiation and conductivity part of their heat to the adjoining elements which melt. Moreover, the molten mass is kept constantly in motion by the action of the are produced under the foot of the electrodes, and by the descent of the comparatively cool mixture into the molten mass. This results therefore in an energetic mix ing insuring perfect homogeneity of the finished product which can thus be made, ac-

cording to the mixture employed and to the products to be manufactured, pasty liquid or extra fluid by superheating.

The accompanying drawing given merely by way of example, shows an electric furnace in vertical section.

At its lower base is arranged the hearth 1 made of refractory materials and provided at the sides with a lining resisting the destructive action of the molten products. The hearth plate 2 of the furnace is constituted by a conducting pis (rammed earth) resting on a current-supplying plate connected to the conductor bar 3. The arch of the hearth 1 is connected to the shaft 4 of the furnace and leaves a passage for four electrodes 5 connected by cables 6 to the other conductor bars 7. The number of electrodes varies according to the intensity of working to be obtained, the nature of the current, the method of connection and the shape of the hearth. The electrodes 5 are operated by means of winches 8.

The materials brought ona truck 9, are discharged into a receiver 10 where they are dried by the passage of the hot gases escaping through the throat 11, fines 12 and the nace where they are gradually heated as.

they descend, by the action of the heat of the furnace and of the gases of the melting hearth, and the reactions between the va-.

rious elements take place.

The molten-final-product after the operation'" has been properly carried out, is suddenl cooled by water or by air, and cast at regu ar intervals through the orifice 15 into movable molds.

According to circumstances and to the object to be attained, the furnace (an more- 1 Che! over vary in its constructional details, it could be fed by a continuous current or by an a ternating current.

By means of this process, and With the use of an electric furnace, it is possible to obtain hydraulic lime and any desired artificial cements, quick-setting, half-slow, slow-set ting, puzzolan, synthetic, with any indexes of fhydraulicity.

In the same Way, it is possible to obtain any desired hydraulic products, of any composition, according to the mixtures to be treated and to the reactions in the furnace, and oi colors varying from white to blackish gray, by the addition or suppression of reducing agent in the mixture.

This process by fusion in an electric l urnace does not a't 'ect the quickness of setting uts, it is possible to obtain, e mixtures, quick-setting molten t is to say quiclcsetting molten artificial cements.

lt is also possible to obtain hydraulic products or" variable density by the addition or-subtraction or metal oxide, chiefly terruginous, and any silicates of lime, alumifill ll si natcs of lime and silico-aluminates of lime,

and therefore to imitate any natural or artiiicial cement.

The hydraulic products cast are of two classes:

lhose Which alter the cooling disinte grate in the air and are converted into impalpalde powder which does not leave any i'eriduo on screen No. 80. These products ca 31 011, be packed at once Withoutany at], banal treatment; the products removed from the electric furnace are perfectly burnt, as they are molten, and have a great resistance to tension and to compression and are. also hi hly suitable for grinding".

2. 'l 1e products remaining compact during slow or sudden cooling, which are treated sul'isequently liite clinltcrs of cement kilns.

'lhc ditlerence found between the products oi these two classes is due to proportions of silica, alumina and lime used in the mixturcs, and the time oi fusion.

The quality of a hydraulic product, and therefore its ('mumcrcial value, depend not only on careful manufacture, but also on the cluunical constancy of the layers in the quarry used, and on the necessity of treatcomparatively fusible materials at the temperature of cementltilns (1250 to 1-100 degrees lilydraulic qualities are imparted or clayey limcstoucs generally used, by the addition of limestone or lime.

The electric furnace in which very few substances resist fusion, makes it possible to use n'iatcrials which are too refractory for ordinary kilns, and generally speaking, any raw umi'crials the elements of which can enter into the composition of hydraulic to clays Leas es products or be simultaneously eliminated at the high temperature which it develops.

Among the raw materials treated by this process, can be used: i

1. Any primitive rocks: gneiss, micaschists, chlorite-schists and horn blende schists.

2. Eruptive and volcanic rocks; granite, quartz, porphyry, trachyte, basalt, lava, etc., and products of decomposition, sandstone slate, puzzolan, sand, comprising moreover any silico-aluininate of the feldspar class, zeoliths, micas, chlorites, scliists, clays.

3. silicates of lime, iron, groups of augite hornblende and l olivine.

l. Natural silicates 015 alumina such as andalousite, staurolithe.

5. Natural aluminates and bauxite.

6. Pure, magnesium containing' or claylimestones and any calcium compounds such as sulfates, phosphates, tungstates, chloride, fluoride.

7. Combinations of iron, manganese, titanium, tungsten, chromium existing in the state of impurity in the materials hereinbefore specified, or by addition to the mixtures used.

8. Slugs of blast furnaces, acid or basic steel furnaces and electric furnaces with fei'roelloys.

These materials are used in accordance with their analytical composition, with connection of on e or another of theeonstituents, and by addition or subtraction of one or more elements in order to arrive at the desired composition of the final product. The question of fusibility plays a part therefore only in the economical[use of the electrics energy required for the reaction, and the quantity of coal to be fused depends on the quantity of oxide which have to be reduced. It is therefore alwaysv very small, with rare exceptions.

By generalizing its application, thecement industry would cease to depend on 110 special deposits or quarries, but only on cheap electrical. energy produced by Waterfalls. lVater power resources are however very considerable throughout the Whole world, and their position is generally that of the deposits of all the materials to be used. Building of cement mills utilizing this process is therefore independent of the quarry to be Worked, but depends only on the place where installation of hydraulic 120 force will be the cheapest and where the transport of finished products is easy.

Having now particularly described and ascertained the nature of our said invention and in What manner the same is'to be per- 1 7 formed. we declare that What We claim is:

1. The process of manufacturing cement and the like. consisting in grinding and mix jug the constituent material, melting the same in an electric furnace, keeping the 1159 molten mass in motion by the action of the the electric ar until the same is discharged electric arc nntil the from the furnace.

2. The

in an electric furnace, utilizing the heat of the furnace to heat the materials. While chargng the furnace therewith, and keeping the molten mass in motion by the action of process of manufacturing cement t1 and the like, conslstnig 111 grinding and 1111K mg the constituent material, melting the same same is discharged from the furnace.

In testimony whereof we affi'x our signan'esin presence of two witnesses.

MAURICE LUCIEN BOILLOT. JEAN DAUDIGNAG.

Witnesses:

CHAS. P.'PRESSLY, J. LEBSEUR.

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