US1144701A

US1144701A - Apparatus for making white lead.

Info

Publication number: US1144701A
Application number: US64591311A
Authority: US
Inventors: Carleton Ellis
Original assignee: Ellis Foster Co
Current assignee: Ellis Foster Co
Priority date: 1911-08-25
Filing date: 1911-08-25
Publication date: 1915-06-29
Anticipated expiration: 1932-06-29

Description

C. ELLIS.

APPARATUS FOR MAKING WHITE LEAD.

APPLICATION FILED AUG.Z5. 191x.

1 1 44,70 I Patented J 11116 29, 1915.

UNITED STATES PATENT OFFICE.

CARLETON ELLIS, OF MONTCLAIR, NEW JERSEY, ASSIGNOR T0 ELLIS-FOSTER COMPANY, i A CORPORATION OF NEW JERSEY.

APPARATUS FOR MAKING WHITE LEAD.

Application filed August 25, 1911.

To all whom it may concern.-

Be it known that I, CARLETON ELLIS, a citizen of the United States, and a resident of Montclair, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Apparatus for Making IVhite Lead, of which the following is a specification.

This invention relates to a process of making white lead and similar pigments, and to apparatus therefor; and relates particularly to the process and apparatus for manufacturing white lead in a substantially continuous manner: all as more fully hereinafter described and as claimed.

The manufacture of white lead by the old Dutch process involves treatment of the metallic lead under corroding conditions for a space of two or three months, and on account of the protracted time required for the complete corrosion of the lead, together with the labor cost involved in handling the raw and finished product, the cost of manu facturing white lead by this process is relatively high. F or this reason numerous processes have come into existence which involve the preliminary connninution of the metallic lead in some way, and subsequent treatment of the comminuted product with air, carbon dioxid and moisture; sometimes in the-presence of acetic acid or other similar chemical reagents. The old Dutch process as well as the quicker methods of corrosion usually require soft refined lead. Suitable corroders lead generally commands an extra price and is expected to be free from such impurities as iron, copper, antimony and arsenic. If these impurities are present they constitute a source of much trouble and irregularity in the processes of corrosion. Copper and iron both tend to discolor the resulting pigment. Antimony has a peculiar inhibiting action on corrosion. In large proportion it may even check corrosion altogether. Vv'hen litharge is found present in large amount in the corroded stock the trouble may often be traced to antimony. In the old Dutch process the uncorroded lead, buckle residues and the like. are largely removed by rolling and washing. Inthe quirk processes of making white. lead. depending on the corrosion of comniinuted lead by the action of air, moisture and carbon dioxid, with perhaps acetic Specification of Letters Patent.

Patented June 25), 1915.

Serial No. 645,913.

or other acid present in small amount as a carrier, the removal of the unchanged or blue lead presents some difiiculties and in some cases may be' wholly impracticable. Hence complete conversion of the lead would be desirable, or failing that, a method which produces the minimum amount of blue lead and in a form readily separable from the corroded lead. Sandy lead. which forms in the Dutch process when the temperature of the corroding' pots becomes too high. is a crystalline neutral carbrmate. It is dillicui't to grind, lacks body and settles to the bottom of the container when thinned for paint ing. Sandy lead appears in the product of the quick processes, at times, especially if the metallic lead has been poorly or irregularly comminuted and the subsequent process of corrosion, in consequence, forced to the extreme, in an endeavor to overcome the defects of comminution. Again, in the quick processes the hydration of the lead largely precedes the carbonation stage .and in factin some cases it is probable that this separation of the two reactions is essential.

In the present invention hydration and caibmmtion, if desired. may be carried out substantiall simultaneous y, with a consid erable saving in time. alu and apparatus.

The present invention set also that organization which makes P0,..Jlblfi2 the use of hard lead, which leads to the substantial reduction or elimination of blue lead and sandy lead and by substantially continuous operation or non-cumulative handling of the material throughout the major portion of the several operations involved effects a reduction in the cost of manufacture of the product. In the handling of a material involving so great a tonnage as white lead, small reductions in manufacturing costs effect a considerable total saving.

The process herein set forth also involves an especially thorough and uniform comminution of the metallic lead, preferably with the simultaneous formation of a coat ing of a peculiar suboxid on the minute particles or filaments ot' the metal. The hydration of comminutcdlead may lead to the formation of several different hydrates and the progress of carbonation as well as the character of the final product depends very largely on the nature of the initial hydration, which, other things being equal, is

controlled by the degree and uniformity of comminution and the character of its surface coating of oxid, or absence of oxid, as

the case may be. 'Simulutaneous hydration and carbonation of irregularly comminuted lead usually leads to the formation of ob -jectionable sandy lead and excessive amounts of blue lead. I

' The present application contains matter which is contained in Serial Nos. 570,214 and (511.606.

The manner in which the present inven- \tion is carried out will be clear from the accompanying diagrammatic drawings, (not to scale) wherein Figure 1 shows the assembled apparatus in section and elevation; while Figs. 2 and 3 show certain nozzle types or metal atomizers in section. Fig. i shows a centrifugal comminuterin plan view. Fig. 5 depicts a plan view of a set of conveyers-and Fig. 6, shows this construction in longitudinal'elevation.

As stated, the drawings are purely diagranmiatic, for the sake of simplicity of illustration. and are to be regarded as apreferred or illustrative embodiment wherein various changes or modifications may be made without departing from the spirit of the. invention. 7

' In the drawings, 1 is a melting pot having the grate 2. and comminuting nozzle 3.

A pipe 1 extends down through the pot and terminates in the nozzle 3. The latter is fitted with a conical disintegrator 5. Beneath the pot is placed a receptacle (3 having an outlet 7, leading into the conveyor trough 3. The interior of this trough is shown by the eXposed portion or section at 9, where propelling blades are seen mounted on a horizontal shaft. The conveyor and its various parts should be constructed of mate-- rial which has no discoloring action. on the product. In order to aiford proper time contact the conveyor is of very considerable length. jacket 10 is provided. into which steam ma y be admitted through the pipe 11; an outlet beingprovided at 12. ()r 12 may be. used as the inlet and 11 the outlet according to circumstances. \Vhen cooling is required, cold water may be admitted into this jacket to control the reaction. Inlets, 22. 2 -3 and 21 and also 25, 26 and 27 are provided for the introduction of air. moisone end 28 to form a. nozzle opening 29.

plied with

Metal duets

32 and 33 terminate within this casing-to form tips or metal nozzles angu larly disposed with respect to each other, f y as shown by 30 and 31. An air or steam pipe; 35 terminates in the nozzle 35' adjacent to the

metal tips

30 and 31.

In Fig. 3' an annular chamber '31 is sup-l air, steam and the like by the 37 and 38. 36 is the

metal sup

39 and 10 are conical disintegrators placed in front of the casing 3, in

inlet pipes P y P P operative relation to the tip or nozzle thereof.

-' In Fig. & a rotatable drum 41 contains the molten metal, which is discharged through the outlets 442. 13 is an annular slot through which air, steam and the like are discharged 7 against the issuing streams of molten metal.;

The operation of the apparatus under the present invention is as follows :\Iolte1r lead or any suitable lead alloy fills the melting pot 1. The metal, preferably should be in a super-molten condition. or at a temper ature some or 500 degrees above the 111eltiD"f P0iI1t. The c lumn of metal preferably snould be high so as to furnish a very great pressure or head at the nozzle 3. The

metal is allowed to pass slowl} into the com-.

minuting nozzle 3 and air or steam under high pressure introduced by the piped. Connninution of the metal takes place and I as the stream passes through the conical connmnuter 5 further reduction occurs, due

in part to vortex action of the air or steam current. The hnely db and wired rawing vided metal is collected in the chamber 6 J and is discharged from thence in a regulable is passed slowly along the conveying cl1an1- her and is there Sllhjtttfll to the action of manner into the. converting conveyor It moisture and oxygen or a r to accomplish jacket in lieu of steam. Car on dioXid may lhe material is at length discharged from I or begin the reaction of hydration. In the 4 case of a hard lead steam ma): he admitted into the jacket 10 to hasten the reaction- Very reactive leads may lmiliil'e cooling. inv j which case cold water is admitted into the also be introduced into the conveying chains! her in order to secure )artial carbonation.

the first conve ver or conveyer system and passes into the separator 1-t where it is freed from undesirable metallic particles and thus purified it passes into the carhonatingcham her 17 where. in contact with moisture and carbon (lioxnl. and air if necessary. hnal' conversion takes plaee'and the product discharged at 21. After drying the producta is read} to be packaged for shipmcpt ground in Ull. 'lhe' comminuting nuz herein shown are depu-ted in several espeeially to emphasize the neces ity of cart- I ful and uniform comnnnution of the metal to an excessively fine state. '1 he importance,

of length of travel of the hydrating and car bonating mass is also emphasized. The time contact factor may be increased without unduly increasing the length of the conveying system by the cyclic or shunt treatment shown in Figs. 5 and 6. In Fig. 5, which is a plan view of a set of conveyers, 44 represents the feed end and 46 the discharge end. 45, 47, 4S and 49 indicate conveyers operating in a manner to propel the material as indicated by the arrows. In Fig. 6, which is a longitudinal elevation of Fig.5, the conveyer 46 is shown as somewhat elevated above the bottom of the other conveyers, thus forming the dam 50. One or more of these cyclic or shunt conveyers may be placed in the conveying line of the hydrating and carbonating apparatus above set forth. The operation is as follows ;material traveling along the

conveyer line

44 and 45 reaches the dam 50, where the lighter portion of the material passes on by way of the conveyer 46. The heavier portion is caught by the conveyer 47, delivered to conveyer 48 and from thence by conveyer 49 reaches the feed end 44, thus making a complete cycle or shunt return. Meanwhile hydration or hydration and carbonation are in progress as the material is being constantly subjected. to corroding infiuences;air, water, steam, acetic acid, carbonic acid and the like, so that on arrival again at the dam 50 more conversion has occurred and the lighter products pass away by the conveyer 46. Fresh material is sup-' plied constantly at the feed end 44 to make up the loss by withdrawal of the material in an advanced stage of corrosion at 46.

Ordinarily it is not necessary to make use of acetic acid or other strong chemical agent, as air, moisture and carbon dioxid together reacting on the comminuted lead of a substantially uniform degree of extreme fineness accomplishes this result effectively and produces a pigment of especially high covering power. The use of acids or other reagents is not however debarred in the present process. Instead of air, pure oxygen or oxygen and nitrogen mixtures having the former component in larger proportion than is present in air, may be used. A high oxygen content leads to more rapid oxidation and hydration. The influence of temperature also is marked, slight increases in the temperature showing an immediate response in the rate of hydration. The eifect of using a high concentration of carbon dioxid, especially in the later stages of carbonation is also noticeable. Lime kiln gases, carefully washed, carrying 30% to 40% of carbon dioxid are useful. Pure carbon dioxid also may be used. A mixture of oxygen and carbon dioxid, without any diluting gas, may be used for forced operation.

As stated, the degree of fineness of the filamentous or comminuted lead is a most important consideration. Excessive comminution to a degree double or triple that heretotore practised in the art is one of the first considerations leading to a high grade product of pronounced covering power. So far as I am advised, ordinary impingement of a jet of air or steam and the like has not been carried out in a manner afiording. a product of the requisite degree of fineness to make possible the substantially continuous hydration and carbonation of a traveling stream, yielding a product of a satisfactory amorphous and free-working qualities. This defect of imperfect comminution may be in part due to the cooling effect of expansion of the compressed fluid jet. 3

For example, superheated steam under high pressure, suddenly ejected through an orifice and expanded to atmospheric pressure, falls 1n temperature sometimes many hundred degrees through absorption of heat adapted to comminute lead to a product of extreme fineness, a conveyer of great length adapted to propel the comminuted product, a shunt return forming a part of said conveyer, means for contacting said product while in said conveyer with air in the presence of moisture; whereby said product is hydrated; a separator connected with said conveyer adapted to free the hydrated material from substantially all metallic particles, a second conveyer adapted to receive and propel the hydrated material from said separator, and means for introducing carbon dioxid into'said second conveyer; whereby the hydrated material is carbonated.

2. An apparatus for making white lead comprising a receptacle for holding molten lead, adjacent thereto a metal atomizer adapted to comminute lead to a product of extreme fineness, a conveyer of great length adapted to propel the comminuted product, means for contacting said product while in said conveyer with air in the presence of moisture; whereby said product is hydrated; a separator connected with said conveyer adapted to free the hydrated material from substantially all metallic particles, a second conveyer adapted to receive and propel the hydrated material from said separator, and means for introducing carbon dioxid into said second conveyer; whereby the hydrated material is carbonated.

3, Apparatus for making White lead comprising a receptacle for holding molten lead, adjacent thereto a metal atomizer adapted to comminute molten lead to a finely divided product, a conveyer adapted to propel the comminuted product in contact with moisture and with oxygenating and carbonating gases, and interposed in said conveyer a separator adapted to remove metallic par- I ticles from the material.

day of August A D. 1911.

Witnesses NATHANIEL L. Fos'rrm, CHARLES WRIGHT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.

OARLETON ELLIS.