US1670049A - Production of solid finely-divided material - Google Patents

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May 15, 192s; 1,670,049-

L. scHER-r'sl. E1' AL' PRODUCTION 0F SOLID FINELY DIVIDED MATERIAL Filed Nov. 14. 1922 Y. fasi-sam j 22 @my Fig. 3. (ANB Inventrs:

Patented May l5, 1928.

UNITED STA res . LUDWIG SCHEBTEL ANI)A WILLI ITY, lF ESSEN, GERMANY, ASSIGNORS TO THE FIRE TH. GOLDSCHMIDT A.G., OF ESSEN, GERMANY.

IRODCTION 0F SOLID FINELY-DI'VIDED MATERIAL.

Application led November 14, 1922, Serial No. 600,882, and `in Germany November 15, 1921.

This invention relates to the production of solid finely divided material, such as lead oxid, suitable for compositions, and various similar uses.

In a general aspect the invention consists in the provision of a process wherein raw material, such, for example, as molten metallic lead'or pulverulent lead oxid, is distributed over and permitted to-vaporze l0 from surfaces of an inert refractory material which is heated to a temperature of the order of 1000 degrees C.; and at the same time hot gases or products of combustion are permitted to flow over the surfaces thereby causing the formation of a fume of lead oxid which is removed from the region of the hot surfaces and collected in a suitable manner to obtain a high yield of material in a state of extreme sub-division.

If molten lead be employed as thef-raw. materialthe hot gases are of an oxidizing nature in order to convert the metal vapors to oxid. If lead oXid be employed as a raw material the hot gases may be products of combustion. In either event a relatively 'large volume of gas is employed to effect the formation of a fume which is highly'` dispersed'through the gaseous medium, and to obtain a high proportion of nely divided material with a proportionate decrease in thev amount of coarser particles. Coarse particles contained in the eflluent mixture of gases and fume are permitted to settle out under the influence of gravity and the cleaned fume is then collected or precipifated by a suitable means such as an electrical discharge.

In the accom anying drawing; Fig. 1 is sc ematiclongitudinal crosssectional view of an apparatus for practic-v ing our invention.

Fig. 2 isl a schematic longitudinal crossjf. sectional viewf another type of apparatus,; and

Fig. 3 is a transverse cross-sectional view taken along the line A--B of Fig. 2.

Referring to Fig. 1, there is illustrated a tower 1 of refractory material, in whlch 1s disposed a stack of refractory bricks, 2, which are slightly spaced from each other and provide a large surface area, and which are so arranged as to permit the passage of hot gases between thel bricks. An inlet port 3, formed at the bottom of the tower 1, vis provided for the admission 0f hot gases from a suitable source, not shown. The upper end 1a of thev tower is ,of somewhat larger cross-sectional area than the base thereof to effect a decrease in velocity of the gases prior to their emergence from the tower. Positionedabove the tower isa receptacle or hopper 4 in which is disposed a quantity 4a of raw material such as molten metallic. lead or lead oxid.

The hopper 4 is provided with a port 5 opening into the tower 1 above the stack of bricks 2, which may be opened or closed by manipulating a valve 6. An exit port 7 is provided at the upper end of the tower 1, and to itis attached a pipe line 7n which terminates in an electrical precipitating apparatus 8. The framework of the member 8 is connected to one pole of a. generator 9, or other source of electricalenergy, the other pole of which is connected toA electrodes 10 disposed within the chamber 8. Under the influence of the electrical discharge, fume carried into the chamber 8 from the tower 1 is precipitated, andthe conveying gases are permitted to escape through a port 11. The precipitated material collects in a receptacle 12 disposed be- 'low the chamber 8 and may be removed therefrom through a gate 13.

The apparatus shown in Fig. 2 comprises a. shell 20 having a lining of refractory material and an inlet port 21 for, the admission of hot gases. A rotatable shaft 22, extending through lthe shell 20 is provided with a v bore to permit of water cooling, and has mounted thereon at intervals a pluralityof perforated discs 23, consisting of, or covered with, 'refractory material. The shell. 20,is adapted to receive a quantity of molten material 24. The discs .23 rotate within the bath 24, and carry above it thin films of raw material which is vaporized, converted to a fume by gases entering through the pipe 2l, and removed to a suitable settling and precipitating apparatus through an exit port 25.

In both types of ap ar'atus there -is provided an extensive sur ace area upon which the raw material may be distributed and from which itis vaporized .and converted to a fume.

Referring again to Fig. 1, in operation, the-tower and contained brick-work 2 are brought to -a suitable temperature. (about 1000 C.) and .molten material, y,such as lead,

'nsl

i's allowed to trickle through the port 5, fall as aspray, and distribute itself as a thin film over the brick-Work. Here it is vaporized into the surrounding atmosphere and converted into a fume held in suspeiision by the large .volume of hot,- gases entering through the port 3. Coarse particles of marefractory surfaces of large area. owinging volatilization, excessive temperaturesneed not be employed, and a high yield of finished material is obtained.

It is apparent that the principles ofthe` invention may be applied with various types of apparatus, and that the operating conditions indicated above may be varied to meet the necessities of any case. Thus, the` rocess is applicable to the formation of ely divided antimony or tin compounds, which we regard as equivalent to plumbiferous substances. In makina` antimony trioxid, for

example, the cylinder 20 is partially filled with molten antimony monoxid, or if desired, With molten antimong, in which case' ustion are usedv steam and products of com for heating and diluting. If antimony sulfide be employed, a limited quantity of air is used With the steam in place of products of combustion.

What we claim is:

1. The process of preparing litharge in a state of fine sub-division from simple plumbiferous material free from sulfur and halogens which comprises dispersing lthe yraw material, distributing the same over heatedhot gas over the surfaces to -effect the volatilization of the raw material, cooling the v volatilized material and eil'ecting the settling of particles of largersize from the resultant fume andv subjecting the fume to the action of a precipitating means to form a finely divided litharge.

2. The process -of preparing finely divided materials frorn simple plumbiferous materials :free from sul ur and halogens which comprises distributing the same as a film over heated refractory surfaces of large area, passing a current of gases around the surfaces, thereby effecting the volatilization of the raw material as a. fume suspended in the gases, and subjecting the fume to the action of a precipitating means to separate the suspended material from the gas as a finely divided mass.

3. The process of preparing linelyl di.

vided .materials from metalliferous materials which comprises sub-dividing the Inaterial, passing the same through a shaft and over an extensive surface of refractory material inert with respect to the material and at a high temperature, flowing a current of hot gases over the material to eiect its vo1a tilization and to form a fume suspended in the gases, withdrawing the gaseous mass'and precipitating the fume.

.4. The process of preparing litharge fin a state of extreme sub-division which comprises melting simple plumbiferous material free from sulfur and halogens, dis ersing the same over a-large area of heate refractory material, passing a counter current of hot gases over the-surfaces, volatilizing the plumbiferous material, cooling the same to form a fume suspended in the gases, separating coarse particles by gravltal action, and precipitating the suspended fume from the gas to yield a finely dlvided litharge.

In testimony whereof, vwe aix our 'signatures.

. DR. Isa. Lui-)WIG SCHERTEL.

DR.' ING. WILLI LTY.

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