US694138A - Process of manufacturing white lead. - Google Patents

Description

Patented Feb. 25, 1902.

F. J. CURBETT. PROCESS OF MANUFACTURING WHITE LEAD.

(Application filed June 9, 1900.) (No Model.) 2 Sheets-Sheet I.

| I 61;?- az 'Li 'EE d6 J 1. H

z W 6 3 f C e. t, 67/ l I 1 Z/ 5 I 5 9 L 5 z WITNESSES I IN VE N TOR %2 ATTORNEYS TM: "cams mews on. Pnoroumu. wmmmon, o. a

Nu. 694,l38. Patented Feb; 25, I902.

F. J. conssn.

PROCESS OF MANUFACTURING WHITE LEA D.

(Amilication filed June 9, 1900.

.(lo Iflodel.) 2 Sheets-$heet 2.

I WITNESSES: E 7 m 1 611 .zzm dz-Zvfi; Mfi Mu v ATTORNEYS we NORRIS wzrzas an. wnbroumamumncron. o. c.

UNITED STATES PATENT EErcE.

FREDERICK JOHN OORBETT, OF PRAHRAN, VICTORIA, AUSTRALIA.

PROCESS OF MANUFACTURING WHITE LEAD.

SPECIFICATION formingpart at Letters Patent No. 694,138, dated February 25, 1902.

Application filed .Tune 9, 1900. Serial No. 19,661. (No specimens.)

To all whom it may concern.-

Be it known that I, FREDERICK JOHN Con-- BETT, a subject of the King of Great Britain and Ireland, residing in the city of Prahran, county of Bourke, State of Victoria, Australia, have invented certain new and useful Improvements in Processes of Making White Lead, of which the following is a specification.

The object of this invention is to provide a cheap and rapid process for the manufacture of whitelead and one which can be carried on in a closed apparatus,so as to be non-in j urious to health. For this purpose the invention consists of the process herein described of making white lead, which comprises the steps of mixing aldehyde and acetic acid in substantially the proportions specified, introducing lead oxid into the solution, agitating the mixture, simultaneously subjecting the same to contact with carbonic-acid gas, permitting the mass to settle, drawing ofi the supernatant liquid, and heating the precipitate to a temperature suiflcient to expel the liquid remaining therein.

In the accompanying drawings, Figure 1 is a front view, with parts broken away, of an apparatus in which my improved process can be carried out. Fig. 2 is a side view of the apparatus, also with parts broken away; and Fig. 3 is a detail section through one of the floats of the apparatus.

Similar letters of reference indicate corresponding parts.

Referring to the drawings,Aindicates an upper reservoir, which communicates by a pipe a, having a valve a,with a carbonatin g chamber 0, provided with an agitator c, journaled therein, and of any suitable form for agitating the contents of the chamber.

B is a hopper provided with a dischargetube b and valves 1) 6 said discharge-tube communicating at its lower end With the carbonating-chamber. The valves U12 are connected by a handled lever bipivoted at a point between said valves to a post b on the tube b, so that said valves can be simultaneously operated in opposite directions.

From the lower part of the carbouatingchamber extends a pipe 0, having a valve 0 and communicating with the interior of a settling-vat D. The upper part of the carbouating-chamber is connected by a valved pipe n with the upper part of the vat D. Two of these vats, with their connecting-pipes c'n, are arranged as shown in Fig. 1. Within each vat is arranged a float d, counterbalanced by a weight d, which is connected with the float by awire d passing through the top of tho vat D and over a pulley d mounted rotatably upon an arm 7' of a standard 1", rising from the floor R or from any other point of support. To the float is connected a flexible siphon-pipe e of rubber or other suitable material, located within the vat D. The float cl is made of wood or other suitable material of sufficient lightness as to float upon the surface of the liquid employed and is provided with a bore d, extending through the same. A coupling d connects the pipe 6 with said bore, said pipe being by the bore placed in communication with the portion of the vat below the float. The upper end of the flexible tube e is connected with a valved pipe e, which passes through the wall of the vat at the upper part of the same and thence iu downward direction, its lower end being connected with the spout g of a suitable distilling-pan Gr. Each vat D is connected at its lower end by a suitable valved pipe g with said vacuum-pan G, and the latter is provided at its interior with an agitator G of any suitable construction, the shaft g of said agitator being journaled at its lower end in, a cross-bar g? of the pan and at its upper end in a cap g of the spout g of the pan and provided outside of the same with a bevel-gear g or other means for operating the same, as shown in Fig. 1. The lower end of the vacuum-pan is connected by a pipe t', having a valve 2', with pipes W, deliveringinto settling vessels I. The wall of the pan is provided with observation-windows on. To the outer end of the spout g of the vacuum-pan is connected the condensing-coil F, which is surrounded by a suitable liquid vessel, if provided with an overflow f, the whole forming a condenser for the vapors distilled off from the material in the pan. The lower end of the coil F passes through the vessel f and delivers into a lower liquid-reservoir A. This is a closed vessel, and from the upper portion of the same rises and then descends a pipe 0 into a vessel 0, filled with glycerin or any other suitable material, thus forming a seal permitting the escape of air or gas from the vessel A, but not permitting ingress of the same through the pipe 0. To the coil F below its tankfis connected by the pipe f an air-pump E, which pump also communicates by pipe f with the tank A. From the upper portion of said tank A a pipe a runs directly to the upper liquid reservoir A, and from the lower portion of said tank A a pipe a communicates with the pump E, and another pipe a connects said pump with the upper reservoir A.

For carrying out my improved process in this apparatus a solution of from thirty to ninety per cent. of aldehyde and seventy to ten per cent. of commercial acetic acid of thirty-five-per-cent. strength is placed in the upper reservoir A. In case as low as thirty per cent. of aldehyde is used a part of the balance will be made up of waterthat is to say, the entire seventy per cent. remaining will not consist of acetic acid, but a proportion of said seventy per cent. is preferably water. A quantity of this solution is allowed to flow from the reservoir A into the carbonating-chamber, so as to fill the latter somewhat less than half full. The hopper B having been filled with litharge, a quantity of the same is permitted to flow through the discharge-tube b into the carbonating-chamber, the valves 1) 19 serving to measure off the quantity admitted, and said quantity being sufficient so that with the solution already in the chamber said chamber is filled approximately half full. The chamber 0 is provided at its upper portion with an inlet-tube t, communicating with valved branch tubes 25 25 A pressure-gage t is connected with said tubes between the valves i, so as to show the pressure in the chamber 0. The pipes t are connected with suitable sources of carbonic-acid gas and compressed air, respectively. After all the cooks are closed on the carbonating-chamber the agitator is started and carbonic-acid gas and compressed air allowed to .enter the chamber for from thirty to sixty minutes, the time depending upon the pressure employed of the gas. The mixing operation having been completed,the contents of the chamber are permitted to fiow through the tube a into one of the settling-vats D. Here the same is allowed to settle, the solid matter, which may be termed the precipitate or sludge, settling to the bottom of the tank, while the liquid, which is the same as the original liquid, it having undergone no change, stands supernatant upon the sludge. The valve 2 of the pipe e is opened, and the air-pump E is started, whereby a suction is created in the pipe f, coil F, spout g, pipes e and e, and bore d so that the liquid in the vat D is drawn up through bore d and flexible tube 6 and flows down through c, g, and the condensing-coil F, the whole forming a siphon, the action of the pump E being continued, if necessary, to carry on the operation. The liquid of condensation is discharged by the coil F into the lower tank A. The sludge is now permitted to flow through the comparatively large connecting-tube g from the bottom of the settling-vat D into the vacuumpan G. The pan G is provided with a jacket G to which steam is admitted by the valved supply-pipe k, which is connected with any suitable source of steam. The valve e is.

closed and the pump E set in operation, so,

as to reduce the pressure within the pan. The spout g of the pan is provided with a checkvalve so as to maintain the vacuum in the pan. By the heat and the reduction of atmospheric pressure, the remaining liquid in the sludge is rapidly and thoroughly driven off. The mass is agitated by the agitator G, which facilitates the distilling operation. When reducing the pressure within the vacuum-pan, the air removed by the pump E is drawnthrough the spout g, coil F, and pipe f and delivered through pipe f into the tank A, from which it is forced by the succeeding quantity of air in outward direction through the pipe 0, escaping from the latter be low the level of the liquid in the vessel 0 and bubbling up through said liquid. The vapors of aldehyde and acetic acid, together with whatever water-vapor there may be, condenses in the coil F, and the liquid collects in the tank A. The pump and agitator are stopped when the distilling operation is complete, and atmospheric pressure is restored in the vacuum-pan by a suitable vent-cock a, such as shown at the upper portion of the pan in Fig. 2. Oil is then admitted to the pan through a suitable pipe 0. and the agitator again set in motion, so as to thoroughly mix the white lead with the oil. The quantity of oil admitted depends upon the quantity of white lead in the pan G, and in any case is sufficient to render the mixture fluid enough to be drawn off through pipes i 2' into the tanks I, where it is allowed to settle and is then removed for packing or use. The liquid collecting in the tank A is pumped, by means of the pump E, through pipes a a? up to the tank A for use again in the process. The vent-cock n of the chamber 0 serves for restoring atmospheric pressure in the chamber prior to the admission of another charge of litharge and solvent fluid. The pipe 11, with its valve n, afiordscommunication between the chamber'C and the vat D, so that any desired pressure of gas can be exerted on the surface of the mass in the Vat for assisting the discharge of the same through the tube g into the pan G when the valve 8 of said tube is opened.

The process has been described in connection with only one of the settling-vats D. As a matter of fact, however, it is advantageous to operate the two settling-vats-that is to say, charging'them alternately from the carbonating-chamber O and discharging them alternately into the vacuum-pan G. The time necessary for the settling of each charge in the settling-tank is from three to six hours.

In place of aldehyde and acetic acid alcohol and acetic acid in substantially the same proportions may be employed.

I am aware that heretofore processes have been proposed in which litharge or lead oxid was mixed with water and the mixture subjected under agitation to contact with carbonic-acid gas and the water afterward expelled from the resulting white lead by heat. White lead, however, has a strong afiinity for water, and the complete removal of all aqueous moisture from the white lead was a very diificult part of such a process and required subjecting the white lead to heat for a considerable length of time. By my process, however, this objection is entirely overcome. The mixture of aldehyde and acetic acid is expelled from the white lead quickly and thoroughly, and high heat is not required. Furthermore, it is possible to employ with the aldehyde or alcohol and acetic acid a considerable proportion of water, for while water in itself is stronglyheld by white lead, as above referred to, the presence of aldehyde or alcohol serves to neutralize this afiinity, so that the water is entirely expelled from the white lead at a temperature not greatly exceeding the temperature required to expel the alcohol or aldehyde and acetic acid alone. A cheap and rapid process for the production of a superior quality of White lead is thus provided.

Having thus described my invention, I

claim as new and desire to secure by Letters Patent 7 1. The process herein described of making 7 white lead, which consists in mixing aldehyde and acetic acid in substantially the proportions specified, introducing lead oxid into the solution, agitating the mixture, simultaneously subjecting the same to contact with carbonic-acid gas, permitting the mass to settle, drawing off the supernatant liquid, and heating the precipitate to a temperature sufficient to expel the liquid remaining therein,

substantially as set forth.

2. 1 The process herein described of making white lead, which consists in mixing aldehyde acetic acid and Water in substantially the proportions specified, introducing lead oxid into the solution, agitating the mixture, simultaneously subjecting the same to contact with carbonic-acid gas, permitting the mass to settle, drawing oEE the supernatant liquid, and heating the precipitate to a temperature sufficient to expel the liquid remaining therein, substantially as set forth.

In witness whereof I have hereunto set my hand to this specification.

FREDERICK JOHN OORBETT.

In presence of- EDWIN PHILLIPS, CECIL W. LE PLASTRIER.

Images