US391159A - Process of making chlorine - Google Patents

Description

3 Sheets-Sheet 1. J. A. JUST.

PROCESS OP MAKING GHLORINE.

Patented Oct. 16, 1888.

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(No Model.) 3 Sheets-Sheet 2. J. A. JUST.

PROCESS 0F' MAKING GHLORINB. Y 110.891,15). Patented 001:. 16, 1888.

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PROCESS OP MAKING GHLORINE. No. 391,159. Patented Oct. 16, 1888.

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JOHN A. JUST, OF SYRAOUSE, NEV YORK.

PROCESS OF MAKING CHLORHNE.

SPECIFICATION forming part of Letters Patent No. 391,159, dated October 16, 1858.

Application filed April 14, 1888. Serial Nn. 270,709. (No model.)

T0 LZZ whom, it may concern.'

Be it known that I, JOHN A. JUsT, of Syracuse, in the county of Onondaga, in the State of New York, have invented new and useful Improvements in Processes of Making Chlorine, of which the following, taken in connection with the accompanying drawings, is a full, clear, and exact description.

rlhis invention relates to an improvement in processes of producing chlorine; and it consists in thenovel combination of materials and the practical utilization of chemical reactions taking place at certain temperatures, substantially as will be hereinafter more fully described and claimed.

In order to enable others skilled in the art to which my invention relates to avail themselves of its benefits, I will now proceed to describe its use and operation, referring to the accompanying drawings, which I have prepared to enable me to more clearly and fully describe my process and to enable others to more easilyT understand its working, and in which- Figure l is a diagram view of such a plant as I prefer to use in carrying out my process. Fig. 2 is a detail section ofthe devices for recovering the manganese dioxide and nitric acid. Fig. 3 is a detail section of 011e of the stills,showing its connections to the pipe systems and manner of operating the Siphon. Fig. 4 is a sectional View of the washer; Fig. 5, a plan view of the siphon-trap, and Fig. 6 a cross-section of the evaporating-pan.

For the better carrying out of my invention on a large scale I use a still or series of stills, connected in one or more rows termed batteries,77 which are varied in number and size according to the capacity of the desired plant. I place the series of stills constituting a battery in a trough, c, preferably of wood, lined with sheet-lead of requisite strength, as at a', and in the bottom of the trough I place a coil of steam-pipes, c2, for heating the stills,as will be more fully explained hereinafter.

Fach still composinga battery is an earthenwarejar, b, resembling those often used in chemical processes and apparatus, and is provided with a removable cap or cover, b', the rim of which tits intoa groove in the top of the jar, as at b2, and this groove is provided with a water seal, into which the rim of the cap enters, and this opening is thus effectually sealed against the admission of air or the escape of gas from the still.

Upon one side the still is formed with a vertical passage, c, in its side opening inwardly at its lower end and outwardly at its upper end,and to this latter opening is secured a rubber tube, o', provided with a glass tube, c, which is extended down and connects with a trap, c3, connected to a drain-pipe system, as will be presently explained, and this device acts as a siphon to clear the still after the operation is completed upon a charge.

Vithin the still is plaeeda perforated vessel, d, to receive the charge, and at the top of the still is an opening, d', also provided with a cap and a liquid seal, at which point the acid used is entered from a system of distributingpipes; also at the top of the still is formed a nozzle, d2, connected by a pipe, d, with a system of pipes for carrying oif the gas formed in the still, and each still ofthe battery is separate and independent and independently connected to the pipe and drain systems mentioned, so that each still may, as desirable, be operated independently ofthe others.

The different pipe-lines referred to are run as follows: A receptacle, c,- of proper size and material, divided into two compartment-s to receive the two acids, is provided with apair of faucets, e. These faucets discharge into a single main acid -pipc, e2, extended in the proper direction, and this main pipe is provided with one, two, or more branches, e3, which are extended along beside and above the series of stills forming the batteries, and are provided with outlets and cocks 6*, by which the acids are supplied to the stills through the liquid sealed opening prepared for that purpose in the stills, as already described; and it will be noted that by a proper arrangement of stop-cocks, &c., the acids are supplied to any or all of the stills at pleasure and in accordance with the number to be charged.

The pipe-linef, with which the still-siphons connect, may, if desired, be laid in the ground, and its branches and main line lead directly to a cistern or well of proper material, into which all the residue liquor of the stills is conducted after the charge has been worked.

The main and branch gas-main g, into which IOO the chlorine gas generated in the stills is discharged, leads directly to a suitable washer, g', where it is deprived of all moisture it may contain, and from thence is extended to the chloride-oflime chambers.

For the recovery of the acid and manganese used I provide a furnace or oven, l1., having a large pan contained therein, (not necessary to show in this connection,) into which the residue liquor from the well is placed and heat applied. The gas liberated by this operation escapes by a pipe, h', and the manganese dioxide is left in the pan in a perfectly pure form, dry, and ready for use again at any time. AThe pipe h conducts the nitrous vapors arising from the reaction in the furnace to a tower, h2, (shown in detail in Fig. 2,)through which they rise in la zigzag course to the top, a pipe, h5, admitting atmospheric air to mingle with the vapors, and at the top of the tower a spray of water is admitted, which runs down and serves to condense the vapors as they pass over the zigzag shelves of the tower. This water and condensed vapors are carried off directly to the last jar of the series of condensers and circulate back toward the first one in the opposite direction to the course pursued by the vapors still uncondensed. From this the uncondensed vapors are conducted through a cooler or condenser, 7c, to the rst one of a double row of jars, 7c', through which they pass from jar to jar 'till arriving at the last,

from which they are led by a pipeJcZ, to a sec-` ond tower, m, where they are effectually condensed, and through a small pipe, m', again to the last jar of the series. It will thus be seen that all the manganese dioxide and all or nearly all of the nitric acid used in the process is recovered and reused indefinitely by the arrangement of plant herein shown.

It will now be understood that I do not in this application confine myself to this or any other particular plant or apparatus, and have only given a general description of such a plant as is readily used in order that the process proper, which I shall now proceed to describe, may be the more readily and easily understood. It is, in fact, merely by way of illustration, and I have not entered into a description of its details, nor do I make any claim for it herein, as I intend to make it the subject of a separate-application for apatent as the preferred form of apparatus used in carrying out my process for the manufacture of chlorine.

I iill the lead-lined troughs in which the generators or stills forming a battery are placed to a proper depth with a strong solution of calcium chloride, serving as a bath, which is heated by means of the steam-pipes to the necessary degree of heat to drive oft from the stills all the chlorine contained in the charge.

seines The ingredients used in my improved pro'- cess are nitric acid, hydrochloric acid, and manganese dioxide, and I nd by experiment the best proportions of these ingredients for producing a perfect operation and result are as follows: 3.3 equivalent of nitric acid (NHO) and 3.2 equivalent of hydrochloric acid, (HQ) or fourhundred andlifteenpounds ofnitricacid at 1315O specicgravity,andthreehundredand thirty-one pounds of hydrochloric acid at 118()o specitic gravity, and one hundred and fortyone pounds of manganese dioxide, (MnO,.) Veaker acids will accomplish the same result, but not as completely and economically, since the residue liquor after the operation is iinished is much more diluted than if stronger acid had been employed. The stills are now charged with chemicals in proper proportions, the nitric acid being first run into the stills, then the hydrochloric acid. When the battery of stills is thus charged with the required amount of acids, the manganese dioxide for each still, having been previously prepared, weighed, and placed `conveniently at hand, is placed in the perforated vessel in each still, preferably by means of a wooden funnel of sufficient size to reach nearly to the liquid,and

so prevent splashing. The cover of the still is then at once replaced in its liquid seal, as the evolution of chlorine commences at once on the insertion of the manganese dioxide, and this chlorine gas passes oli' at the proper outlet and into the gas-pipe system, as previously explained. In charging a battery of stills it is always advisable to supply acids, beginning at the iirst still in order, and from this consecutively through the row, as the acid-pipes are given a slightincline, and this modeof procedure gives a chance to drain out the pipes after the' charging is completed. perature supplied by the steam-pipes and the bath in which the stills are placed is such as uor remaining in the stills is drawn off into the mainfand conducted to the well or cistern.

In the chloride-of-lime chambers, upon the lime placed therein to be converted into chloride of lime by the action of the chlorine gas,

is usually found a hard and thick superficial` crust, which is formed from the beginning by reason of the lime too greedily absorbing the gas, and this prevents or greatly impedes the further absorption. It has been customary to open the chamber and break up this superficial crust or turn the lime over to expose the less chlorinated lime from the bottom to the action of Vthe chlorine, in order that the chloride of lime should be brought up to proper ICO The tem- IIC and even strength. This annoyance I overcome and greatly facilitate the operation as follows: To the ehlorinegas pipe, before it reaches the chloride-of-lime chambers, I supply a quantity of air-say from twenty to thirtytive per cent-and I find that this not only facilitates the production of the chloride of lime, but it also prevents the formation of the crusts above mentioned and gives me a better result in consequence.

In the manufacture of chloride of lime, at a stage when the lime in the chambers is nearly saturated with the chlorine, some pressure accelerates the process very much and produces a stronger article. This has heretofore been generally effected by steaming, but I find I can perform this to much better advantage by the use of compressed air, which is always readily had in chlorideAof-lime and acid works, and is much more economical, as well as more advantageous, than the old steaming process.

The next step in the process is the recovery of the nitric acid and manganese dioxide from the residue manganous nitrate liquor which has been run into the well or cistern from the worked-out stills. The residue manganous nitrate is now brought into the furnace and de livered in the large pan contained therein. The fire is very gradually brought up, and at iirst watery vapors escape, and the liquor is thus concentrated as the heat ofthe liquid increases. These watery vapors may be allowed to escape, orare condensed in the rst small tower in passing over the zigzag trays therein, the liquid which condenses there being carried off at the bottom of the tower by a glass tube and conveyed to the lastjar of the condensing series, as shown in Fig. 2. From this lastjar it is caused to travel from jar to jar by means of connectiiig-siphons tillit has passed through the system and reached the first j ar ofthe system, and thus the nitrous vapors are compelled to travel in the opposite direction to the water and weaker acids, and in consequence a complete condensation and strong acid is obtained on arriving at the jar nearest the beginning of this condensing system, where strong acid is continually drawn ot't'for use in the generators; also, the water and weaker acid from the last tower which retains the remaining traces of nitric acid which have escaped condensation runs oif at an outlet provided, and also enters the last jar and takes the same course as the liquid entering from the first tower, as just described.

The gases generated by the reduction of nitric acid in the rccoveryfurnace ascend through the condensing and cooling tower, where they are regenerated into nitric acid by an ascending current of air and a descending jet or spray of water, and the escaping and still uncondensed gases, being mixed with air, pass on to the condensing-jars, wherein the weaker acid coming from the lastjar circulates toward the first jar of the condensing system. Thus the gases travel in an opposite direction to the liquid and a practically complete re covery of the nitric acid only depends upon, rst, a complete decomposition in the furnace; second, the thorough cooling of the niter gases after leaving the furnace, and, third, the insurance ofa slight excess of air throughout the whole course ot' condensation.

The decomposition ofthe maganous nitrate in the furnace com menees at a temperature of about 280O Fahrenheit and continues while the temperature is gradually raised to about 380 Fahrenheit to the maximum degree of 400 Fahrenheit, when the mass will be found solid upon the pairbed consisting of very pure maganese dioxide, which isagain used infreshly charging the stills, and the process is thus continuously operated,the manganese dioxide and nitric acid being recovered and reused indefinitely, as described. It will thus bc seen that this process of making chlorine consists really of three stages-viz., the reaction in the stills, the reaction in the furnace, and the reaction in the condensation and recovery ofthe nitricaeid. Stated in chemical formula, these several reactions appear as follows:

Reaction oflirst stage in stills: M11O2+2HN O3+2HCl gives Mn(NO3),+2H,O+ZCl.

Reaction of second stage in furnace: M11(N 03),-l-heat gives l\InO,2N0,.

lteaction of third stage in the recovery of the ruddy vapors: 2NO2-l-H2O-l-O gives 2H NOT This formula will concisely show to any one familiar with the art the successive steps taken and the full practical recovery of the manganese dioxide and the nitric acid. As heretofore stated, I do not desire to confine myself to the proportions of ingredients named or to the strength set forth, as some changes may be made in these details without departing from the spirit of my invention and produce lhe same result; but the strength and proportions named I lind by experiment to be the best for producing atan economical figure the very best results, and prefer them for this reason.

Vhile in theory and in laboratory experiments the results of any chemical process are obtained by the use of the different chemicals in their exact equivalent proportions, yet in the operation of such process commercially on a large scale there is danger of failure by an excess of one over its equivalent of another. Thus in the present instance, should there be in practice an excess of hydrochloric acid over its equivalents of nitric acid and manganese dioxide, all the chlorine contained in the hydrochloric acid used in the charge could not be evolved, and the quantity so left undecomposed remains in the residual manganous nitrate liquor, thereby contaminating the same, causing a complication of resultsin the stage of decomposing said residual liquor. If, upon the other hand, we suppose that the manganese dioxide and hydrochloric acid to be in excess of the nitric acid, such excess of hydrochloric acid will form with its equivalent of manganese dioxide manganese chloride, (MnClz) which on the boiling down of the residual manganous nitrate liquor would contaminate the recovered manganese dioxide and nitric acid. As this acid and the manganese dioxide are used and reused in the continuous operation of the plant, this defect would be magnified with each recovery till it would soon be necessary to discard the reco vered ingredients and' commence with a fresh charge. To obviate all difficulty of this nature, it will be noted that the figures herein .given are not the exact chemical equivalents,

but represent an excess of nitric acid over the hydrochloric acid and an equivalent excess of manganese dioxide. This excess of these ingredients fully insures the evolution of all the chlorine in the hydrochloric acid and leaves in the residue liquor no trace of chlorine to interfere in any way with the complete and perfect recovery of the manganese dioxide and the nitric acid. Special attention is called to this small excess of these two ingredients, as it is an essential to the perfect working of the process on a large scale, and without it failure would soon result.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. 'The withindescribed process of making i chlorine, consisting, essentially, in introducing into a generator nitric acid, hydrochloric acid, and manganese dioxide, the nitric acid and manganese dioxide being in equivalent excess of the hydrochloric acid, and subjecting the generator to heat, whereby allthe chlorine of the hydrochloric acid is evolved, substantially as and for the purpose specified.

2. The process of making chlorine, consisting in charging a generator with nitric acid, hydrochloric acid, and manganese dioxide, vsubjecting the generator to heat until all the chlorine in the charge is evolved, then subjecting the residual liquor to heat 'to decompose the manganous nitrate, and thus manganese dioxide is formed,while the nitrous vapors escape and are recovered as nitric acid, substantially as set forth.

3. The process of making chlorine, consisting in charging a generator with nitric acid, hydrochloric acid, and manganese dioxide, subjecting the generator to heat until all the chlorine gas is evolved from the charge, then decomposing the residual manganous'nitrate liquor by heat, when manganese dioxide and nitrous vapors are formed, and finally withdrawing the nitrous vapors into eondensers, where they are brought into intimate contact with air andvwater, and thus the nitric acid is yrecovered by condensation, substantially as JOHN A.v JUST.

Witnesses:

\W. G. MCARTHUR,

FREDERICK I-I. Giens.

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