DE1467109A1 - Process for the production of hydrogen fluoride - Google Patents

Description

P 14 67 109. 1
New · documents

E. I. OU PONT DE NEMORS AND CONPANY 10th and Market Streets, Wilmington, Delaware 1969b "Y.St.A.

Process for the production of hydrogen fluoride

The invention relates to the production of hydrogen fluoride, in particular by treating a metal fluoride with a mixture of sulfuric acid, sulfur trioxide and water vapor a temperature which is low enough for liquid sulfuric acid to condense on the metal fluoride and with it can react, and on the other hand has such a high value that the metal fluoride particles do not become sticky.

A paste or slurry of calcium fluoride in sulfuric acid has hitherto been used to produce hydrofluoric acid and the reaction is formed by mixing or stirring the paste or slurry using a suitable heat source carried out. This mixture is very difficult to handle because it adheres to the walls of a pipe furnace or other reaction vessels adheres and on the apparatus with which the

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Implementation is carried out, cake or putty-like wet forms. This increases the efficiency of the heat exchange very bad, which seriously limits the output, and kicks also a serious disruption of an effective and economic Maintaining a desired temperature. The bad blurring also leads to a bad one Contact of the acid with the caloluirifluoride.

The present invention overcomes these shortcomings in the prior art of the technique.

The subject of the present invention is a process for the production of hydrogen fluoride by continuous conversion of sulfuric acid at temperatures from 100 ⁰ C up to the boiling point of the sulfuric acid under the applied pressure with ground metal fluorides in a mobile reaction system without caking of the solid reactants and ovulation of the gaseous escaping hydrogen fluoride, characterized by the condensation of sulfuric acid from a vapor phase containing sulfuric acid, sulfur trioxide and water vapor, preferably in a fluidized bed or a moving bed of a rotary kiln or a kneader, suspended or agitated metal fluoride particles and subsequent reaction of the condensed sulfuric acid with the metal fluoride in proportions such that under the

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Given Druok, the formation reaction and the condensation reaction of the sulfuric acid provide the heat of reaction required for the reaction of the sulfuric acid with the metal fluoride. _k

In the method according to the invention, the parts of the CaloluBfluorldes (or other metal fluorides) are on a Implemented equipment suitable for handling single parts, without any! Time sticky or pasty too * You can easily implement the parts in this way, the reactant cappatures and the resulting calcium sulphate easily pull it out of the reactor. The process is from Calolumfluorld with no substantial sticking feasible on the winches or surfaces of the equipment used. In addition, the use of heat transfer laughing with the problems accompanying these avoided.

The present invention enables the manufacture of Hydrogen fluoride from any alkali or alkaline earth fluoride. At Orund the low cost is essentially off Calclumfluorld preferred fluorspar.

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Oeuäaa of the invention is made using liquid Sulfuric acid kept the temperature as low as necessary and the reaction device heat by means of vapor Sulfur trioxide and water vapor are supplied. The released Heat corresponds to a large extent to the heat of reaction of the sulfur trioxide and steam. It has been shown «that one In this way the strength of the condensation of the sulfuric acid on the Caloiunfluorid-Teilohen carefully in equilibrium can hold. The amount of sulfuric acid condensed on the particles should be sufficient for rapid conversion to result in »but never be so large» that the particles become sticky and consequently the disruptive ones Form a paste or sticky mass.

The method according to the invention is given below of the drawings. In the drawings in a thematic representation shows:

Fig. 1 shows a two-stage fluidized bed implementation according to the

Invention"
2 shows a one suitable for the method according to the invention

Device with moving fluidized bed »

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Pig. J5 a reaction device with meohanisoh moving

Layer that is calibrated for discontinuous operation. tion of the method according to the invention is suitable, and

4 shows a suitable for the method according to the invention, continuously operating rotary reaction device.

The device shown in FIG. 1 is viewed from above and below. On or into the fluidized bed in the head part 4 of the reaction device 3 is through the inlet 2 liquid sulfuric acid 1 injected. The fluidized bed 5 is made up of calcium fluoride parts and reaction products thereof formed.

Through the supply line 6 the head part 4 are constantly Calcium fluoride .particles supplied. Under the retaining screen 7 an inlet 8 for sulfur trioxide vapor is arranged. Through the same inlet δ there is water vapor together with hydrogen fluoride and sulfuric acid vapor Introduced from the lower reaction chamber 9 via pipeline 10. The mixture of water vapor, hydrogen fluoride, Sulfur trioxide and sulfuric acid vapor happened

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aas sieve 7 in the upward direction and holds the particles for the Implementation in vortex state.

Jae calcium fluoride reacts with the sulfuric acid condensing on its surface to form hydrogen fluoride and calcium sulfate. Since the conversion takes place over a longer period of time, partially converted calcium fluoride particles flow through the overflow downpipe 11 into a lower fluidized bed 12.

In the lower layer 12 there is a further conversion of the partially converted calcium fluoride-calcium sulfate particles and a stripping of free sulfuric acid from the particles. The particles entering the lower reaction zone carry on their surfaces condensed sulfuric acid; the further reaction takes place using superheated steam, which is generated by the steam inlet Ia88 13 is introduced and also the particles in the vortex state holds «The converted calcium sulphate particles flow through a Overflow line 14 from; and through the pipe 10 is made the head of the lower reaction chamber 9 of the upper chamber 4 gaseous hydrogen fluoride together with water vapor and sulfuric acid vapor fed.

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The product is received at the top of the upper reaction tank k at an outlet 15, which is provided with a conventional dust collector 16 and a conventional washing device 17, in which the latter entrained sulfuric acid and water vapor are removed by waaohen with concentrated sulfuric acid. The product hydrogen fluoride is condensed by cooling and collected as the process product. Dust components removed from the gas stream can be discarded or recycled to the reaction device.

Instead of the Wlrbeleohioht reaction device described above with reference to the drawing can also work with modified devices, such as a reaction device elnar single vertebraeohioht. A single reaction device had to be bigger than the one in Flg. 1 explained to be held » but the Qesam implementation can also be done in a small container perform in a satisfactory manner. Under these conditions, steam "is supplied to the ground" gave a single temperature and the other reaction conditions choose so that what overflows from the vertebrae Out largely formed by calcium sulfate or that the calcium sulfate is largely in the Oas product atom is carried out with.

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At another, appropriate for the implementation of the procedure The type of device suitable for the invention can replace the fluidized bed described above by a moving bed will. Working with moving layers is an established method for carrying out a gas-solid reaction This type of device is used here as a reaction device "With a wandering layer".

A suitable moving sheet device is shown schematically in FIG. In the reaction device 41 is introduced through the supply line 42 cold calcium fluoride, which in the direction of the arrows, the layer 43 directed at Temperature conditions migrated steadily during the implementation. The temperature is the same as in the fluidized bed process directed by supplying liquid sulfuric acid through the supply line 47 to the bed. The obtained by this procedure Calcium sulfate is removed by appropriate means such as a screw 44 near the bottom. In the usual A holding screen 45 is provided.

The calcium fluoride particles used here can and do not need to have the fineness of the fluidized bed process. Usually the potassium fluoride is said to be the usual pVaxis accordingly in the form of comparatively porous pellets approximately 3.2 mm (1/8 inch) in diameter.

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As with the fluidized bed process, when working with the * migrating bed near the bottom of the reaction device through inlet line 46, vaporous sulfur trioxide and superheated water vapor are introduced. The hydrofluoric gases containing off are discharged through the outlet 48 and cleaned as with the fluidized bed technology and collected as a product «

Instead of moving bed or fluidized bed technology, a screw conveyor, rotary kiln, a heavy kneading machine or another device suitable for achieving contact with gas and pesticides. Two types of such devices which have been found to be of value are illustrated in FIGS.

According to Fig. 5, water vapor 49 is passed through a heat exchanger out and mixed in a T-piece 52 with sulfur trioxide vapor. In the reaction device 54, a batch of Meca.tlfluorid is in the compartment 57 by the lifting devices or Moved blades 55, which sit in the rotating shaft 56. The moving layer in zone 57 is through a baffle separated from the dust settling chamber 58. Floodplain of zone 57 in the hydrogen fluoride-sulfuric acid vapor product stream with « discharged metal fluoride settles in zone 58 large part. The gas flow exiting through tube 62

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consists of hydrogen fluoride, sulfuric acid vapor, something subpended Calcium sulfate, smaller amounts of metal fluoride and other reaction products. In the dust collector 63, the dust in the gas stream is collected and as a waste residue discarded. The product hydrogen fluoride in the effluent gas is collected and purified, which is according to the appropriate Methods happens.

When working in practice, a batch is created through the extension tube 53 Fluorspar entered and preheated with hot air, which enters through line 66. You then begin with the task of Water vapor and Sehwefeltrioxyddampf and controls the moisture of the water vapor by means of the heat exchanger 50 so that in the Reaction device will sehalten the condensation of sulfuric acid at the desired value. While the Calcium fluoride will gradually increase the temperature of the reaction zone to remove the free sulfuric acid in the layer in the To keep the area in which caking and agglomeration of the layer occur minimally or not at all. After finishing treatment of one batch, the residue is discharged from zone 57 through pipe 61 and discarded. The one in the zone 58 collected dust contains unreacted fluoride, which is discharged through the sowing pipe 59 and circulated to a following batch in zone 57 is returned.

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According to FIG. 4, water vapor is introduced through the pipeline 65 and with sulfur trioxide vapor entering through conduit 66 mixed and the mixture obtained is introduced through pipe 67 into the reaction device. The reactive soldering device There is also a circumferential HUlIe 70 with lifting shovels 71 is provided, which absorb the layer material and throw the solids through the vapor space. The rotating reaction device is provided with suitable seals 68 and 74 provided to prevent air from entering the or a Leok leakage of process gases from the reaction device su prevent.

Implemented RUc test and β good flows into the stationary one Extension tube 69. Calcium fluoride 79 is continuously introduced from the screw 75. The condensation of sulfuric acid on the layer is applied in the manner according to the invention by spraying the liquid acid supplied through the lines 72 steered at 73. In the residue discharge end of the reaction device the complete course of the reaction is brought about «and excess, unreacted sulfuric acid can be used

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largely due to the high temperature sulfur trioxide-water vapor mixture are evaporated from the residue. The effluent product gas, which contains the hydrogen fluoride contains, flows through the pipeline 76, with the dust located in it for the most part through the dust collector 77 is removed and the hydrogen fluoride then through the pipeline 80 to a conventional Samrael and purification plant got. The dust collected in the dust collector 77 is passed through the conduit 78 and the screw 75 to the reaction device returned or can be discarded »

In the above examples, the solids become too large Part in countercurrent to the gas A cocurrent flow? · has not only proven to be feasible, especially with devices similar to FIG. 4, but also offers some advantages. So one can have adequate condensation steering with a smaller number of sulfuric acid »3 injection points preserved» In the case of direct current flow, a gas consisting essentially entirely of calcium sulfate can be produced from the gas flowing out Dust can be removed that can be discarded without recirculation »

With the countercurrent flow, there is a slight evaporation of the Sulfuric acid from the residue possible and the sulfuric acid is better used, d. H. a more effective transformation

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the same obtained in metal sulphate «The sulfuric acid evaporation can also be carried out with the direct current flow by suitable injection an inert substance such as air or hydrogen fluoride itself can be obtained from the outlet side of the reaction device can return in the cycle »around the dew point of the sulfuric acid in the last parts of the discharge end The reaction device can be increased by suitable use of inert substances in cocurrent or countercurrent operation one also includes the dew points throughout the reaction device

steer so that the number of sulfuric acid spray points so can be greatly reduced.

With the fluidized bed there are certain advantages due to the more intimate mixture »the better heat and mass transfer and other advantages that are inherent in this working technique. The particles lie in the fluidized bed apparatus in a "boiling" state and are held in a state of suspension while moving fairly roughly. The types of apparatus with mechanical movement as in FIGS. 3 and 4j can be prevented while maintaining the cake formation Features of the invention with a slightly higher content of free sulfuric acid than the fluidized beds operate

In the process according to the invention, calcium fluoride can be used

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of the type normally used for hydrogen fluoride production. In view of the low content of silicon dioxide, it is preferred to work with a fluorspar of the "acidic" commercial grade. The grain size of such commercial products usually has the values listed in the trade as "70 # by 200 mesh", "77 $ by 200 mesh", and the like. An even finer fluorspar can be achieved by grinding to the desired size, and the fluorspar can also, as mentioned above, optionally be converted into larger particles by pelletizing _e

When working with a fluidized bed, the choice should be made Grain size of the fluorspar and the design of the device below Consideration of the considerations normally applicable to fluidized bed work. You need in this way of working an equilibrium between the grain size, the grain mass, the gas flow rate, the volumes of the gases used, etc. It is essential to balance these factors Expert familiar.

The sulfuric acid used should be an acid containing at least 90 μl and preferably 98 to 100 % H ₂ SO ₄ . If more cooling is desired in the process, a more dilute sulfuric acid can be used. For example, a sulfuric acid with 78% HoSOj (60 ° Be) has proven to be satisfied-

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proved, and even this acid can, if desired, be further diluted with water. An easier cool down can be done by injecting water into the system. In Fig. 3, according to which water vapor with the formation of a vapor-liquid mixture is cooled, is practically a Y / aesinjection before. Usually the more concentrated sulfuric acid (like 98-100 #) is preferred to meet the need Sulfur trioxide to decrease · With some types of devices one can nooh further reduce the soulfur trioxide requirement by means of fuming sulfuric acid «

Instead of temperature controls of the type described above, all of the sulfuric acid can be used in the form of sulfur trioxide and supply steam and regulate the temperature by evaporating liquid hydrogen fluoride. A recirculation of cooled gas is also feasible.

In the method, further Sohwefeltrioxyd as obtained by distillation of fuming sulfuric acid, sulfur trioxide _t supplied. Normally the saturated steam that is available at the factory is supplied, but if superheated steam is conveniently available it can also be used. The use of superheated steam can, as in the device of FIG. 1, bring about an improvement in yield. With superheated steam at a temperature of 400 to 500 ° C, for example, the calcium sulphate in the last

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Stripping off sulfuric acid at the driving stage. Such stripping results in residue materials that are also suitable for the market.

The total amount of sulfuric acid used in the process according to of the invention (as sulfuric acid or in the form of sulfur oxide and water vapor) is introduced, the stuohiome » α trisohen need to be exceeded slightly. Usually the acid in an 0 to 10 »preferably 2 to 5% excess, based on the complete conversion of the fluorspar, used. One can work old larger surpluses, receives but a waste of acid, and extreme excesses occur due to excessive condensation on the fluorspar easy trouble. The fluorspar can also be used in excess, with the calcium fluoride yield sinks. It is therefore preferable to use an excess of acid in order to reduce the cost of the raw material to improve the yield obtained.

Sulfur trioxide is normally used according to the invention in such a proportion in relation to the water vapor and the concentration of sulfuric acid that one can use one

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Water-sulfur trioxide equilibrium of approximately 1 mole of water ie mole of sulfur trioxide is obtained. An overall ratio of sulfur trioxide to water corresponding to 98 to 99 # sulfuric acid has proven to be particularly advantageous. Larger ratios can be used, but lead to a stronger formation of fluorosulphonic acid. Smaller ratios can be used with a certain corresponding increase in the moisture content of the product gas stream. If instead of an anhydrous product, an aqueous hydrofluoric acid is desired, one can apply conditions, the sulfuric acid concentrations of 90 i> or more are equivalent. If hydrogen fluoride concentrating systems are provided, one can also work with small ratios to produce anhydrous hydrogen fluoride, which correspond to weak sulfuric acid concentrations.

The temperatures maintained in the reaction zones are of great importance. The temperatures should be natural below the boiling point of sulfuric acid (maximum 335 ° C at atmospheric pressure), which is important because to achieve the sulfuric acid on the calcium fluoride particles reacts more rapidly must condense. The optimal temperature in a given stage or section of a reaction apparatus corresponds to the value at which sulfuric acid condenses at the rate at which yours

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Reaction takes place without producing enough free sulfuric acid, to obtain caking or, in the case of a fluidized bed device, a level of fluidization. ! This temperature is a function of the gas flows, the fluoride content of the layer, the type of device and the ι Gaezueammensetzung.

The temperatures should be in the interest of a rapid Umeeteung approximate a value of 300 ° C or more than is practical, taking into account all other factors and can go up to the boiling point. High temperatures increase the amount of sulfuric acid that is in is discharged with the product gas stream, and enlarge auoh the resulting Oaswaschproblea «temperatures in the product gas outlet zone of up to 250 ° C have proven particularly satisfactory.

The temperature is intended to achieve the most efficient work on the other hand, have such a value that the vapor pressure of fluorosulfonic acid (that at atmospheric pressure at 163 ° C boils) exceeds its partial pressure in the gas stream. at At a lower temperature, there is a loss of hydrogen fluoride due to discharge as fluororeulfonic acid in the potassium sulfate residue a. Temperatures between 100 and 335 ° C at atmospheric pressure are therefore particularly suitable.

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As described generally above, the exact temperature will be according to the invention in a given device under given conditions so that the amount of on the

Galoium fluoride partohen condensing sulfuric acid not enough to make the partohen sticky eu maohen · The procedure Carrying out this can easily observe and the temperature using appropriate amounts ah sohwefeltrior and adjust water vapor on the one hand and sulfuric acid on the other hand up or down.

The temperatures should sum at the end of the calcium fluoride conversion EU have a value near the upper end of the range, in order to keep the amount of sulfuric acid that can be discharged from the system «as small as possible, and near the point at which the hydrogen fluoride is sucked in, the amount of the sulfuric acid vapor continues to decrease which is carried along by the product and which has to be condensed and recycled. In the one here This kind of temperature gradient results because the liquid sulfuric acid is close to the head of the device The column shown is introduced and the superheated steam and sulfur trioxide are added near the bottom, which also applies to the rotary contact device according to Pig. 4 applies. In the case of the reaction pre-

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directions of the rotary or Sohwerkneter design is hinsiohtlioh the temperature at the exit end a compromise is necessary to the sulfuric acid discharge in the back and gas flow to be optimally designed *

The pressure at which the procedure is carried out affects the temperatures at which you can work successfully. For example, the use of positive pressures allows condensation the sulfuric acid on the particles at temperatures higher than those mentioned above. Working in a vacuum is set in in the same way the sulfuric acid condensation and allows the use of lower temperatures. By riohtige Selection of pressure, temperature and device size reads the method would therefore enjoy the invention at almost any temperature Above the value »at which sulfuric acid and oaloium fluoride begin to respond, d. H. about 100 ° C, carry out

The walls of the reaction devices should be kept warm be to eu a condensation of sulfuric acid on them prevent what with an external heating, such as with steam or by electrical means. In many cases, the walls need to be insulated. The wall temperature can of course depend on the vapor pressure of the sulfuric acid vary in the respective zone

ORIGINAL! NSFECTED

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When using a fluidized bed, the device is in Welae familiar to the expert according to the Qrüese of Particles and the Qasnengen to be used selected. With reaction devices In this way the speed of the gas flow obviously depends somewhat on the amount of gas can or must be used in the implementation If desired, can nan by introducing an inert gas »like Air or hydrogen fluoride increase the velocities of the currents in the vortex system. One receives on in this way also a lowering of the partial pressure of sulfuric acid, so that slightly lower temperatures apply '

without excessive condensation and sticking the GaIciumfluoridee occur. As mentioned above, you can inject acid with the correct control of these factors zoom out or turn off.

The calcium fluoride enters into the reaction without converting it State, but is naturally subject to implementation A partial conversion to calcium sulfate very soon, so that the largest part of the conversion takes place on a calcium fluoride-calcium sulfate particle In different stages the conversion into calcium sulfate takes place.

The following examples serve to explain various Embodiments of the invention without the invention being restricted to them «

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In a device in the ark silted in fig. 1, 102.1 kg of Handela fluorspar of the expensive type are introduced with a huge grain size, since out «1» passes through 2OO-Maeohen-8 sieve sa Tt +.

It above level 5 is kept at a tea temperature of about 335 ° and at a pressure which is above atmospheric pressure. prlt »t _r Into the !!! catenary θ are 771.1 kg of sulfur trioxide daaipf old at a temperature of about 100 ° 0 and in the lufUhrleitunß 13 are 181.4 kg to 260 ° 0 superheated steam ▼ on 0.7 at · ing» leads. Aue the dust collector 16 is about 172.4 kg-Caloiuneulfat Ruoketand be removed, which contains less than 1 i Sohwefelelfure free.

Since 16 hydrogen fluoride oae leaving the dust collector, the sulfuric acid vapor and mist, silicon tetrafluoride and other, minor impurities, is used in the Mass Washer 17. You washing liquid by Sulfuric acid and other impurities previously removed from the eyelet is formed, is cooled and circulated through the scrubber of the water is kept constant by the continuous drainage of liquid. The derived acid is through the

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Feed line 2 as described above, see the reaction «- Device and / or we removal of solids filtered and used as a feed for other processes in which an approximately, * contaminated Sohwe * FelsMure usable 1st. The one leaving WKsoher 17 Hydrogen fluoride-That is condensed by Purified by distillation and a hydrogen fluoride of excellent quality in excellent yield collected.

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Example 2

In a device of the type shown in Fig. 2 108.9 kg fluorspar pellets (hoohporös, diameter about 3.2 mm, made of commercial fluorspar of the acidic variety τοη such a grain size that the out a 200-Masohen sieve au 77 i happened) introduced through the supply line 42. Through the feed line 47, 0 kg of fresh, 99% sulfuric acid are introduced into the layer 29 in addition to the recycled acid from the waste gas scrubber. 93.9 kg of carbon dioxide at 150 ° C. and 20.9 kg of steam at 0.7 atm are mixed, and the material is introduced through the feed line 46. Layer '43 is maintained at approximately 250 ° C under the above conditions.

The hydrogen fluoride gas, the dust, sulfuric acid vapor and - contains mist, silicon tetrafluoride and other impurities, exits the reaction device through outlet line 48. The gas flow is through a dust Irooke cyclone guided and the separated dust is fed back in the circuit to the reaction device 41. The gases pass a conventional wet washer operated as in Example 1 being, taking the sulfuric acid and other high-quality products that are collected, as mentioned above, continuously through which the supply line 47 leads to the reaction device Aue the gas stream emerging from the Haeswfischer

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the Iluorwaaeeretoff-Oae is condensed and separated. laugh the distillation «the hydrogen fluoride divides an anhydrous ·

Product is a product that is rewarded
Example 3

In a device of the type shown in Fig. J, 36.3 kg Handele-Flueaapat of the acidic variety (with a unique grain grtisee » daaa daa Out a 200-Maeohen-8ieb au 77 £ paaalert) duroh daa Extension tube 53 introduced. The Sohioht becomes «ittela hot air of 400 ° C, which is introduced through the pipe 66 * preheated to about 290 ° C. The air supply is then shut off. Sulfur trioxide is fed with a content of 15 »9 kg / hour duroh the pipeline 51 together with Waaaerdaopf old an Oeaohwindigkelt of 5.6 kg / h. through the pipeline 49 a. The cooling water flowing into the heat exchanger 50 is regulated and slowly throttled so that the low temperature Sulfur trioxide water vapor flow during the first four hours rises to about 320 ° C. Over the next three hours, the bed temperature is kept at around 320 to 330 ° C. In the three hour end period, the high temperature becomes increased at a constant speed from 330 to 370 ° 0.

Duroh the extension pipe 61 22.2 kg RUokatand are discharged » the less than £ 3 unreacted fluoride and less ala

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0.3 Jl tr ·! · Soh sulphurous acid not applicable. Dureli dta Anaataroh »59 are removed 15 * 0 kg of dust, day at« · 12 i aioht uageeetatee Iluotld contains · Duroh dia pipeline 64 are removed during · Ttraaahaa about 21.3 kg of dust », less than ItO Jl nioht uagaaatata · fluoride contains fluovwaaaaratofft eolwaftliäura and other, ttbar the pipeline 65 abatrOaanden diapfe are led through a condenser, and during the filling of the condenser is obtained in waeaer-free fluorwaaeratoff good quality ·

Belaplel *

i
Zn a device in Pig. 5, 58.1 kg of sodium fluoride (old of a large grain size that out of a 100-Maeohen sieve to 100 i » paaalert) are introduced. This bohioht is kept at around 280 ° C using hot air of 400 ° C, which is introduced through the pipeline 66, whereupon the air is vented. zueaanen with, through the pipe 49, water vapor in an amount of 4.1 kg / hour. introduced. The Klihlwaeaersuatrom au the Wttrmeauatauaoher 50 is regulated and longeaa throttled, that the sehlohttenperatur in the state of the beginning dream of the sulfur oxide waaaerdampfötroaa rises to about 320 ° 0. The eye temperature is kept at about 320 bla 330 ° 0 for a further three hours.

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By daa Aneaterohr 61 27 "2 kg Rliokstand are discharged, is less ala 3 t nloht uagceetstca latrtuafluorld and contains less than 1/2 i" free sulfuric acid. By daa Ansäterohr 59 5 "4 kg dust auagetragen, represents less than 15 1» nioht uagesetstes latrlunfluorld contains. Approximately 30 _{tons of} 4 kg of dust " containing less than 1 + nioht uageaetstea Hatrumfluorld""are grounded while the Varauohea is removed through the pipeline by Deetallatlon dea condensate · an anhydrous fluorohydrate of good quality is obtained.

example %

In a device of the In PIg. 3 aged species are 54 »4 kg Barlua fluoride (old from a large grain size, daaa daa Gut ein 150 Maaohen sieve su 100 ^ paaaiert) duroh daa Aneaterohr 53 introduced. Sleae Sohloht is made using hot air of 400 ° C, which is introduced through the pipe 66 «on about 280 ° C preheated »whereupon the air supply is switched off will. Sulfur oxide vapor is poured through pipe 51 in an amount of 12.3 kg / hour. auaanaen old, through the pipeline 49f Waeeerdanpf in an amount of 2.7 kg / hour. introduced. The Kuhlwaeeersufluee bu den Wäraeauatauaoher turns 50 bo regulated and slowly throttled that the sole temperature

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in the course of the 6-3td.-initial soul dreams dee Bohwefeltrioxyd-Waeaerdainpf-Strom dough to about 92%. Dl · 8ohiohttenperatur will be about 525 to 335 ° E for another hour held.

45 to 4 kg of RUoketand, which contains less than 3 tons of liquid fluoride and less than 1/2 % of free sulfuric acid, are applied through the anaate tube 61. 4.1 kg of dust, which contains less than 10 % unreacted barium fluoride, are removed through the anaati tube 59. Duron dl · drilling line 64, approximately 22.7 kg of dust are removed during the experiment, which is less than 1 £ umgeaetstea contains barium fluoride. The hydrogen fluoride, the sulfuric acid and other vapors which flow off through the pipeline 65 are passed through a condenser, and an anhydrous hydrogen fluoride of good quality is obtained by distilling the condensate.

Example 6

Xn is a device of the type shown in 71g. 4 bowled kind is about the Conveyor screw 79 commercial fluorspar (with a unique grain teas, since the estate happened a 200-Maeohen-Sleb su 70 jC) of the sour variety Alt a speed τοπ 45.4 kg / 8td. Introduced · Through the pipe 66, sulfur oxide vapor is introduced of 0.35 atU Druok and 100 ° C at a rate of

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28.6 kg / 3td. And through the pipe 65 saturation of 0.35 atli is old at a speed of 6.4 kg / h. sugefUhrt and mixed in the pipe 67 with the sulfur trioxide. Through the spray nozzles 73 sulfuric acid (concentration 99 #) is fed in at a rate of 23 # 1 kg / hour. The speed of the acid consumption during each of the spray tubes distributed over the length of the reaction device is directed so that the free sulfuric acid in the Sohicht in the total Reaktlonevvoriohtung is kept below 10 % . The temperatures of the soles in the reaction device gradually rise from about 180 ° C near the end * at which the Pluasepat is introduced, up to about 330 ° O at the end of the residue discharge.

Calcium sulphate is discharged from the analysis tube, which contains about 2 pounds of non-dissolved calcium fluoride and about 1 + free sulphurous acid. Through the pipeline 76, hydrogen fluoride, which contains silicon tetrafluoride, carbon dioxide, carbon dioxide and carbonic acid vapor and mist, and dust escape. Practically the whole Caloiuafjuorid-ataub and a large part of the Oalolumulfat-dust are removed in the dust-frookensammler 77 and circulated surilokfUhrt. In the conventional way, the gas stream flowing off via the pipeline 80 is wet-washed with sulfuric acid and the product hydrogen fluoride is condensed and purified «,

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To carry out this workload with oil flow naturally requires a reversal of the temperature gradient the Sohioht in the reaction * device.

The purity of the starting materials used in the examples was at least 99 * 5 % in Barlunfluorld, at least 99 % in the case of sodium fluoride and 97.5 % in the case of potassium fluoride, via the purity of the hydrogen fluoride obtained, the degree of metal fluoride used and the percentage The following table gives information about the yield of hydrogen fluoride 1

1 2 3 4th 5 5 ; Muuner's examples 24 86 10 11 6th 81 Purity of procedure
rensprodukts in Oe-
; wlohtsprozent
¹ hydrogen fluoride 80 80 93 95.3 97.2 96.6 Imposition of the
used metal
P fluoride in Oewiohts-
percent 76.3 77 #> 92.5 .95.3 97.2 9 ** 0 Percentage Auebeu
te of fluorine water
material

30 -

9098A5 / 1233

Claims (2)

U67109 IA K I d Ft d V d C 524 f 67 9 Ψ 9f K. I. du Foot de Vtnoun and Conpany 5249-1 / 2-0 / P 32 010 Pitinttnipyflehi 1. Process sub Production of hydrogen fluoride by continuous use of sulfuric acid at temperatures of 100 ° 0 Ms aw Boiling point of the sulfur elure under the applied pressure % hydrogen fluoride »» tekennseiohnet through the condensation of soapy water from an oaapfpliase »which contains sulphuric acid ·» Sehifefeltrloxid- and Hasserdaapf, on preferably in a Vlrbelsehloht or a different view of a rotary kiln «or a riveting part of the net in aolehen Mmeenverhlltniesen "that under dea genes Druek the Bildungereaktion and KondensationsretJction the SehwefeisKure · old dea NetaUfluorid erforderliehe lleaktlonswlrae provide for _Λ the Ussetsung the Sohwefeleatr * 2. Method according to claim 1, dtdureh gekennselohnet that aan the Saapfphase is generated by using sulfur trioxide and water and Sohwefeltlure in liquid Vora and / or Oaapffoni outside or inside the reaction vessel in such a way foresees that given dea la Keaktlonegeflas Oruok the required Realctlonewlrae is delivered 909845/1233
- 31 - New document & n (Art. 1 51 ««. 2 No. ι? - ^ _s d « ^ _tninQta ^ _v . 4. _g . ₁₉₆₇₎ 5249-1 / 2-0 U67109 at Method according to claim 1 or 2, characterized in that · « one for further control of steam composition. Warmth· An inert gas such as hydrogen fluoride or air is added to the content and dew point. Method according to one of Claims 1 to J>, characterized in that the temperature of the reaction system is controlled by adding liquid hydrogen fluoride to the reaction mixture or the gas stream. Method according to one of claims 1 to 4, characterized by that Calolumfluorld is used as the metal fluoride. A method NaOH claim 5, daduroh in that the reaction is carried out in a temperature range of 100 ° to ⁰ C j535. 909845/1233 -YY- Blank page