US1959305A - Process and apparatus for recovering barium sulphate from barytes - Google Patents

Description

M. J. RENTSCHLER l,959,305 PROCESS AND APPARATUS FOR RECOVERING BARIHUM SULPHATE FROM BARYTES May l5, 1934.

5 SheetS-Sheet l v -Filed July, 1932 May 15, 1934- M. J. ENTSCHLER I v 1,959,305

ROCESS AND APPARATUS FOR RECOVERING BARIUM SULPHATE FROM BARYTES Filed July 8, 193'2' -5 sheets-sheet i ll IMI i May 15, .1934- M. J. RENTscHLx-:R 1,959,305

PROCESS AND APPARATUS FOR. RECOVERING BARIUM SULPHATE FROM BARYTES Filed Jlily 8, 1932 v 3 ,Sheets-Sheet 5 Patented May 15, v 1934 f UNITED STATES PATENT OFFICE PROCESS AND- APPARATUS FOR RECOVER*- ING BARIUM SULPHATE FROM BARYTES Mahlon J. Rentschler, Willoughby, Ohio, assignor of one-half to William R. Jeavons, Cleveland Heights, Ohio Application July 8, 1932, Serial No. 621,376

12 Claims. (Cl. .2S-122) The sulphide (BaS) is then treated with sodium sulphate (Na2SO4)) which produces barium sulphate according. tov the equation It is apparent that in this process the barium sulphate molecule finally secured is a synthetic product and not one occurring in nature. Furthermore, in practice the products actually obtained are not entirely those indicated by the foregoing equation, numerous other compounds being formed in greater or lesser amounts as well as tliose indicated. Some of these other compounds are undesirable and difficult to eliminate in the finished product.

I have discovered a method of obtaining the natural (non-synthetic) barium sulphate from barytes in a simple, direct and inexpensive manner which results in barium sulphate of a smaller grain size tllan that made by the conventional process while being substantially free from the impurities contained in barytes.

I` am also able by a variation hereinafter described to control the grain size whereby to produce the greatly reduced size or a size even larger than now commercially available as well as various sizes in between.

The principal object of my invention is to provide a method of producing a better quality of bariumsulphate at a lower cost than has heretofore been possible. A further object is to provide a process in which it is not necessary to reduce the ore to powdered form and in which it is notv a transverse section taken on the line 3 3 of Fig. 1; Fig. 4 is a'fragmentary section on the line 4 4 of Fig. 1; and Fig. 5 is a fragmentary vertical section showing a modified form of mechanism for feeding purifying material.

The apparatus disclosed in the drawings will rst be described after which my improved method will be described in connection with the operation of the apparatus.

The numeral 10 indicates generally a receptacle @5 I of such construction that it is adapted to contain a lake 11 of moltenvsodium'chloride or other alkali metal chloride. 'Ihis receptacle may take V the form of a metallic outer wall 12 having a refractory lining 13 composed of material which 70 will not be attacked by the molten salt solution. The receptacle 10 is tiltablymountedas for example on supports 14 about a pivot bar 15. Suitable bearings 16 may be secured to the bottom of the furnace in any suitable manner. Any means 76 may be employed for maintaining the furnace normally in the position shown in Fig. 1 while allowing it to assume a position in which the bottom lies along the line AB. This may take the form of an upright stop 17 having mounted 80 thereon a winding drum 18 upon which is adapted to be wound a cable 19 connected as at 20 to the bottom of the furnace. .The pivot bar 15 is mountf ed slightly to the left of the center of gravity of the furnace whereby a slight holding force is necessary to prevent the furnace from normally assuming a position along the line A-B. A very slight force will then be able to hold itin normal position as shown. It is to be understood that any other equivalent mechanism may be employed for obtaining the same results. At the left hand end of the furnace as seen in Fig. 1 an upward inclination is given to the floor as indicated at 21 for facilitating the removal of sediment through the door 22. Doors 23, 24 95 and 25 and slopes 23a, 24a-and 25a are also provided for allowing access to compartments formed by the partitions 26, 27 and 28. The partition 26 is provided with an overflow opening or notch 29 located adjacent one end thereof. The par- 100 tition 27 is provided with a passage 30 adjacent the bottom for establishing communication' between compartments and is located adjacent the opposite end from the overflow opening 29. The partition 28 has an overflow opening 31 located 105 at the saine end as 29. Liquid passing the opening 29 must sink to the bottom, pass through opening 30 and again rise to the top and overflow 31 into the last compartment C. Inasmuch as all the material passing through theopening 30 110 In practice this may amount to about one ounce per ton of barytes'. The gaseous fuel in the form of a mixture of finely divided` oil particles and air or natural or artificial gas for heating the interior of the furnace to a temperature above the melting point of sodium-chloride or other alkali metal chloride employed may be 'introduced through one or more pipes 32. These pipes may be made of heat resistant material or may terminate outside the receptacle allowing an opening in the wall thereof to constitute the termination of the fuel supply passages.

A combined compressed air and screw conveyor mechanism indicated generally by the reference character D is provided for distributively feeding the crushed ore and additional salt to the surface of the lake 11. Ihis mechanism comprises a hopper 33 having a screw conveyor 34 working in a passage at the bottomthereof. The conveyor 34 may be driven by any suitable prime mover and will feed a predetermined quantity of the material in the hopper to the passage 35 to which is connected a source 36 of compressed air. The material in the hopper 33 will upon reaching the passage 35 come within the influence of the compressed air jet and be scattered over the surface of the lake 11 as indicated in the drawings. A baiiie 37 isprovided for preventing any of the material from passing beyond the lake 11 and falling into any of the succeeding compartments.

g Positioned above the compartment C adjacent the overow opening or notch '31 is the outlet 33 of a feeding means E adapted to supply a decolorizing or purifying material for decolorizing or removing such impurities contained in barytes as are soluble in molten sodium chloride o r other salt employed. This outlet opening is so positioned that the purifying or decolorizing material is dropped into the compartment O at a point where the material is agitated by the cascading of the solution through the passage 31 for the purpose of bringing about mixing in a minimum time. In Fig. 5 I have shown a modified form of feeding means indicated generally by the numeral E' which is .simply an opening through which lumps or aggregations of the decolorizing and purifying material may be introduced. The outlet spout 39 is positioned at such a distance from the inlet opening 38 that the solution will be drawn oi as soon as the purifying or decolorizing material has thoroughly mixed therewith.

This is an important feature of my invention inasmuch as the purifying and decolorizing effects are greatly increased by cooling the material as soon after the introduction of the purifying or decolorizing agent as will allow thorough mixing. In the drawings I have shown only one method of cooling the liquid drawn from the compartment C, namely, discharging it into water in the tank li'.

This method at the same time accomplishes cooling promptly after mixing of'the purifying and decolorizing agent and arrests crystal growth almost at its inception whereby to secure the extremely fine grain size. If it is desired to secure a large grain size the prompt cooling maybe accomplished by a method which will not arrest crystal growth. Forexample, the liquid from the compartment C may be dropped upon a rapidly vrevolving paddle wheel whereby it is formed into a spray for cooling and thereafter may be discharged into water, the time elapsing between cooling and discharging into water servis taken from the bottom, any floating insoluble material will `remain in the second compartment.

ing to control the amount ofV crystal growth and -therefore the grain size.` I may also enlarge the grain size of the line powder' secured by immediately discharging into water and this may be accomplished by boiling such material in hydrochloric acid. The time of boiling will determine the crystal size. I may in this manner produce monoclinic barium sulphate crystals large enough to be seen with the naked eye. The feeding means E may be of any desired construction, that shown consisting `of a hopper 40 and reciprocable ejector 41 adapted to feed the material through the opening 38 at a predeterminedv rate. It is desirable that the feeding unit should be so constructed as not to permit furnace gases to pass out therethrough. A pump 42 is provided for drawing out the barium sulphate in. the receptacle F along with some of the liquid and delivering to filter presses of usual constructionlnfnot y shown). I may, of course, provide means for supplying additional water to the tank F and for agitating the water in such tank, according to common practice in fritting molten liquids.

I provide a stack S normally communicating with the interior of the furnace by an opening s. The stack may be supported independently of the tiltable furnace as indicated in Fig. 3.

In carrying out my improved process the vbarytes ore is washed, dried and crushed preferably to about 4-mesh (size to pass screen of V4 meshes to the inch). It is of great importance that the ,material introduced into the lake 11 be dried since steam formed in the lake would stir up sediment' and prevent proper separation of liquid and solid. It is not essential in my'process as in the conventional oneA described that the ore should be reduced to powdered form; and this is an important advantage in my process, resulting as it does in a considerable saving in the cost of preparing the ore. After crushing the ore is crudely mixed with approximately twice its weight of dry sodium chloride or other alkali metal chloride and the mixture, containing substantially no water, is fed continuously by the feeding means D into the furnace where it falls upon the lake 11 of the molten salt. The temperature of the lake 11 is preferably well above the melting point of the salt (776 C. for, NaCl) whereby the salt particles introduced with the ore are melted substantially instantaneously. The granules or small lumps of ore are dissolved in a very short time and sink below the surface almost immediately, forming no local aggregations in the lake. 1t is aquite important that the Vlake 11 should not be agitated to any great extent either by the introduction of material or any other cause and that the average, over all tem- .perature should be below the point of Volatilization of the salt employed. The compressed air current which carries the charge into the furnace should not interfere with the fuel feed. This temperature will preferably be about 2100 F.` for sodium chloride. By maintaining the temperaturev at this high level and scattering the crushed ore and granular salt-upon the-surface of the lake 11 the formation of crusts of salt on the surface of the lake is prevented and thorough mixing of the ore without considerable agitation -of the lake 11 is facilitated. The barium sulphate contained in the ore together with a limited loating insoluble material.

may be accomplished by tipping down to the position of the line A-B which will'cause most of the liquid to flow into the right hand end leaving the sediment accessible for removal by a furnace hoe or similar instrument. The solution comprising fused salt having dissolved therein barium sulphate and a limited number of impurities flows through the opening 29 and back and forth through the intervening compartments for vallowing further and complete settling of insoluble material after which it cascades through the opening 31 into the compartment C. The material passes from the lake 11 over the partition 26 allowing the settling of heavy particles in the first compartment after which it passes under partition 27 whereby to effect skimming of any When the liquid flows through the passage 31 to the much lower level in the compartment C it agitates the contents of that compartment whereby material from the hopper 40 is quickly and thoroughly mixed therewith. v

The decolorizing or purifying material introduced through the opening 28 from the hopper 40 may be any substance which will effect the desired results, and for many purposes its use is optional.

After the solution has been discharged into .water in the tank F the sodium chloride dissolves out leaving insoluble barium sulphate in salt water which may be ltered olf and washed out leaving substantially pure barium sulphate.

I have found that by the use of this process I am able to secure barium sulphate of a high degree of purity and, if desired, in a very nely divided state, the resulting material having an apparent density substantially one-half that of the present commercial product, and being in a state of division fine enough to pass 99.96% through a screen of 325 mesh. Microscopic analysis shows that 30 particles in a row would pass laterally through the opening in a 325 mesh screen.

The resulting product after having been discharged into water and filtered is strictly neutral, a feature which is of considerable advantage in many uses of the product.

The term granular as herein applied to crushed barytes is not to be understood in a limiting sense, but as describing the size of the crushed orewhich canV be successfully and emciently used within this period of the process described. The size to which the ore is crushed may be larger or smaller than might be understood conventionally by the term granular so long as it is suflciently small that it will be dissolved or substantially dissolved at a point near the top of the lake. It is preferred that the bulk of the ore should be about the size which would be conventionally understood by the word granular, that is, about the size of common cereal grains but a portion may be finer and a portion coarser. There should however be no large lumps and but few lumps vwhich might be considered too coarse to beconsidered granular. These tolerances are to be understood as implied by the. word granular or words of similar import. v

While I have set forth in considerable detail the manner of practicing my invention and' construction of the apparatus employed I Wish it understood that I am not limited to details but only in accordance with the spirit and scope of the appended claims.

Having thus described my invention, what I claim is:

1. In a furnace of thec aracter described, a receptacle adapted to conta a lake of molten material, means for supplying radiant heat to the surface of said lake, and separate means independent of said rst means for distributively feeding granular material to said lake, said last means comprising a container for containing the material to be fed in, means for feeding such granular material from said container at a predetermined rate, and means for distributing the material so fed upon the surface of said lake.

2. A furnace of the character described comprising a receptacular portion adapted to contain a lake of molten material, cover means forming a substantial enclosure for said lake and a substantial space thereabcve, one'or more fluid fuel burners spaced above the lake for heating the same by radiation, and means separate from and independent of said burners for thinly scattering granular material upon the surfaceof said lake.

3. A furnace of the character described comprising a receptacular portion adapted to contain a lake of molten material, cover means forming a substantial enclosure for said lake and a substantial space thereabcve, one or more fluid fuel burners spaced above the lake for heating the same by radiation, and means for thinly scattering granular material upon the surface .of said lake, said means comprising a pipe for compressed gas delivering to the interior of said enclosure at a point vertically spaced from said burners, and means for feeding such granular material to said compressed gas pipe.

4. A furnace of the character described comprising a receptacular portion adapted to contain a lake of moltenmaterial, cover means forming a substantial enclosure f or said lake and a substantial space thereabcve, one or more fluid fuel burners spaced above the lake for heating the same by radiation, and means for thinly scattering granular material upon the surface of said lake, said means comprising a pipe for compressed gas delivering to the interior of' said enclosure at a substantial distance above said .burners whereby not to interfere with the operation thereof or cause incomplete combustion of the fuel, and means for feeding such granular material to said compressed gas pipe.

5. lIhe process which comprises heating by radition a. lake of barytes and molten alkalimetal salt, maintaining said lake placid, scattering substantially uniformly upon a charge receiving portion of said lake drycrushed barytes and dry granular alkali metal salt,l allowing the linsoluble material to settle, and decanting the solution.

6. In the continuous process of recovering barium sulphate from barytes by dissolving the barium sulphate constituent in a molten alkali metal salt, the step of continuously charging the ore into a lake containing the molten salt, said ore being in granular form and the entire charge being scattered upon the surface of said lake.

7.' In the continuous process of recovering barium sulphate from barytes by dissolving the barium sulphate constituent in a molten alkali metal salt, the step of continuously charging a mixture of the ore and the salt into a lake containing the molten salt, said ore and salt being in granular form and the entire charge being scattered upon the surface of said lake.

8. In the continuous process of recovering lll@ lll@

barium sulphate from'barytes by dissolving the barium sulphate constituent in a molten alkali metal salt, the step of continuously charging the ore into a lake containing the molten salt, said` ore being in granular form and the entire charge being scattered substantially uniformly upon a charge receiving portion of the surface of said lake.

9. 'In the continuous process of recovering barium sulphate from barytes by dissolving the barium sulphate constituent in a molten alkali metal salt, the step of continuously charging a mixture of the ore and the salt into a lake `containing the molten salt, said ore and salt being in granular form and the entire charge being scattered substantially uniformly upon a charge receiving portion of the surface of said lake.V

10. In the continuous process of recovering barium sulphate from barytes by dissolving the barium sulphate constituent in a molten alkali metal salt, the step of continuously charging the dry ore into a lake containing the molten salt, said vore being in granular form and the entire charge being scattered upon the surface of said lake.

11.In the barium sulphate from baryts by dissolving the barium sulphate constituent in a molten alkali metal salt, the step of continuously charging a dry mixture of the ore and the salt into a lake containing the `molten salt, said ore and salt being in granular form and the entire charge being scattered upon the surface of said lake.

12. In the process of recovering barium sulphate from barytes by dissolving the barium sulphate constituent thereof in molten alkali metal salt, the step of introducing the crushed barytes continuous process of recovering by continuously scattering the same during a A considerable period of time upon the surface of a lake containing the molten salt.

MAHLON J. RENTSCHLER.

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