DE2139924A1 - Process for the production of sodium bicarbonate, boric acid and / or boron oxide - Google Patents

Description

patsntanwfiute
Dr. Ing. Ä. van d © r Werth
Dr. F. Ledsrer

si Hamburg βθ S * 70/34

Wilatorfer Strasse 32

Solvay & Oie.

33 Rue du Prince Albert, Brussels / Belgium

Process for the production of sodium bicarbonate, boric acid and / or boron oxide.

Priority: 13.8.1970, Luxembourg, No. 61.513

The invention "relates to a combined method which enables sodium bicarbonate, boric acid and / or boron oxide to be obtained starting from sodium borate ^ the usual Cycle of an ammonia soda factory.

It is known that it is possible to obtain a solution of boric acid immediately by adding a solution of ammonium chloride with sodium borates to a boil (PR-PS 292 360), but

subtract or the formation of in order to avoid the reverse reaction, ^^ ^ s ^^ sa Klsc / ammonium borate 3tS8Dggsö ^ it is expedient, the boric acid-containing! fluid during its formation _o

The possibility of precipitating ammonium pentaborate as an intermediate product of this reaction can be used effectively to finally obtain boron oxide (US Pat. No. 2,867,502) These processes turn out to be costly · It consumes ammonium chloride and leaves sodium chloride as byproducts. In addition, it requires a special cleaning system for the mother liquors of the crystallization in order to be able to carry them to the reactor without sodium chloride, and one has to do this with an alcohol-based environment © i & setssn, which way Siittol's distillation is done

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G _e Mäss the invention erhälijman boric acid, by carrying out the reaction between a iiatriumborat Ammoniumehlorid and without the disadvantages of the known processes in purchase.

The invention relates to a process for the production of sodium bicarbonate, boric acid and / or boron oxide while running out Clay sodium borate in the cycle of an ammonia soda factory and is characterized by being the liquid of reacting the filters of the soda factory with a sodium borate in such a way as to obtain:

1) a solution which essentially contains an ammonium borate, sodium chloride and optionally ammonium chloride,

2) a gas phase, which contains ammonia, carbonic acid and water vapor, which is fed into the soda factory.

Solution 1) is heated and cooled sequentially to give:

a) a solid crystallized phase on cooling, consisting of ammonium pentaborate and / or boric acid, wherein the ammonium pentaborate is then decomposed to daw To release ammonia which it contains and to provide either boric acid or boric oxide,

b) a liquid phase, formed by the mother liquors of the crystallization with a content of sodium chloride, ^B 2 ° 3 »a small amount of, ammonia, which was initially present in the solution, and optionally ammonium chloride,

e) a gas phase obtained during the heating of the solution and / or during the decomposition of the ammonium pentaborate Ammonia and water vapor,

The liquid b) and gaseous c) phase are then .geleitet in the Sodafabrik to get in to check a known manner Natriumbioarbonat and a Filtarfltissigkeit mi, which is again, just as bssehriaben treated.

209808/1727

Compared to the known method, the inventive Procedure, the big advantage, the cost of NH.C1 to save, because like the chlorine also the ammonia circulates in a closed circuit.

In addition, the usual by-product NaCl becomes immediate utilizes the mother liquors in a special way through the equivalent extraction of sodium bicarbonate, without the need for it to treat the crystallization in order to separate it from it.

However, it was found that it is important to regulate the crystallization of the boron products in such a way that the mother liquors (solution b) sent to the soda factory do not have too high a content of B ₂ O ₅ , otherwise there is a risk of ammonium borates precipitate in the bicarbonation column. In practice, to avoid this inconvenience in the Kolonneng which operate as usual at about 30 ⁰ C by a maximum of 73 g of B ₂ 0 ~ / kg solution setting at the foot of the column, this condition is met, taking into account the eventual dilutions of CO ₂ and NH ₅ by controlling the crystallization so that the mother liquors of the boron product do not contain more than 78 g B ₂ O ₅ / kg. In order to lower the content of B ₂ O _{5 in} the mother liquors of the crystallization, the crystallization temperature can be

Ι ed θ τι "P ft ^ 1 ¹ ^
low. It is jtadgeitenra & aafe not necessary to go down below O ⁰ C in order to keep the said limit. In practice, therefore, it is kept between 10 and 30 ⁰ G if the ammonium pentaborate is crystallized, and between 10 and 60 ⁰ C if boric acid is crystallized immediately.

The heating of the solution 1) in order to separate the aforementioned gas phase, which contains the greater proportion of the ammonia, can be done by any known means, in particular by Passing through a plate column in countercurrent to steam generated from the solution. Two cases can then appear:

A - If the solution 1) is diluted (less than 100 g BpO, /; one works under higher pressure than in the distillation column of the usual soda factory at a temperature around RO ⁰ C and a

.n

then a solution sufficiently depleted in ammonia to immediately cool the boric acid to such a temperature; to crystallize so that the mother liquors do not contain more a £ a than "78 g B ₂ O / kg. The gas phase obtained during the heating and the liquid phase formed by the mother liquors of the crystallization are then sent to the soda factory

B) When the solution 1) is concentrated (at least 100 g and if one works at atmospheric pressure a little above 100 ⁰ C, one obtains a solution containing ammonium pentaborate. The latter can be separated from it by crystallization by cooling the solution to the extent that the BgO * content of the mother liquors does not exceed the stated limit of 78 g BpO ^ / kg This excess of ammonium chloride ultimately has the effect of lowering the solubility of the ammonium pentaborate, as the following table shows:

Solubility at 26 ⁰ O of ammonium pentaborate in the presence of

and of NaCl (g / kgji

₄ Cl 4-43

NaCl 200 200

(NH ₄ ) _g O.5B ₂ O ₅ .8H ₂ O 150 97

Good results are obtained if the excess of NH.Cl on the order of about 10 # over stoichiometry is.

The gas phase is also obtained in this pail heating, and the liquid phase, formed by the mother liquors from crystallization, is sent to the soda factory.

The ammonium pentaborate crystallized in this way can then:

either thermally dissociated between 600 and 1000 ⁰ C in order to deliver boron oxide and ammonia according to known processes

- 209808/1727

213992A

(see again US - »- PS 2,867,502)

or it can be redissolved to obtain a dilute solution of B ₂ CU (less than 100 g B ₂ O, / kg) which is then treated as under A above to obtain boric acid

The sodium borates that can be used can be borax, kernite and Ezcurrit, but it doesn't go beyond the scope of the invention either, figured out to use other sodium borates, such as sodium metaborates

According to the invention, natural sodium borates can also be used use which contain impurities, especially calcium and magnesium in the forms of ulexite, dolomite, Carbonate and the like, as well as inert components in the form of silica and clay. This is particular the pail at ruler.

In this pool, it is advisable to use the inert constituents but also the calcium and magnesium, which go into solution and interfere with the soda factory. One achieves this according to the invention when one or the other of the following processes is used:

This is solved before the implementation with the filter liquid natural impure sodium borate in aqueous solutions, which contain sufficient sodium bicarbonate or carbonate to the calcium and magnesium in the form, the carbonate and / or To precipitate hydroxide. The precipitate is then separated and the inert constituents and the purified sodium borate solution can then be used as such or after a concentration be used"

The naturally impure sodium borate can be converted immediately with the filter liquid. One then obtains because of the inert ingredients residual sludge, which is separated and washed in a device which follows the reactor In this case, however, it is zwecjfcmässig, the crystallization of secondary Borprodukten as Ezourrit (2Na ₂ O.5B ₂ O ^, 7H ₂ O) and borax pentahydrate (Na ₂ O, 2BeOa.5H ₂ O), because these would be removed with the sludge and would _{mean a noticeable loss of B 2} O ^ (this crystallization

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213992A

tions do not represent a disadvantage in the absence of the sludge, because the secondary products formed were in the Distillation). To avoid this crystallization, one can use three working methods:

1) Use of sufficiently diluted solutions

2) rapid execution of the reaction and separation of the sludge

3) Increase the digestion temperature up to the boiling point to expel some of the ammonia formed and thus shift the equilibrium.

Whatever the working method used, it is also useful remove the soluble impurities like calcium and magnesium.

Cleaning can be done with working methods 1 and 2 by adding sodium bicarbonate or sodium carbonate to the reactor. The precipitated impurities are then eliminated with the sludge »

With operation 3, this addition to the reactor has no effect because of the acidification as a result of the ammonia leaving The calcium and magnesium are then separated from the brine formed by the mother liquors of the crystallization from the desired boron product after the absorption of NH ^ ab, and «was in front of the column of the soda factory. At work However, according to procedure 5, it is found that the dissolved amount of impurities (CaO and MgO) is noticeably reduced, and all the more so when the boiling time is below 15 minutes remains. This enables a significant saving an Reactive for Cleaning «^ This method of working is carried out by the following table explains

209808/1727

attempt G Min. 1 2 - 10 3 - 10 4th - 10 5 - 10 —7— Initial conditions mm ⁰ C 200 200 200 200 Tabel Mineral: tincal ppm Composition: * cm 5.3 5.0 4.7 5.6 lot G 110 110 43 110 48 110 91 110 276 Granulometry e Composition g / kg G <2 <2 99.3 12th 99.4 C 2 98.9 <2 96 Amount of B ₂ O ₃ Na ₂ O g / kg 38.8 38.8 38.8 38.8 38.8 - Digestion solution (NH.) OO Si lot HCl 200 200 90 200 84 200 83 200 86 B ₂ O ₃ g / kg 61 41 32 44 CO ₂ 31 31 110 31 103 31 103 31 126 Exposure 118 118 199 118 188 118 185 128 182 Boiling time 150 150 0.25 150 0.48 150 0.98 165 0.93 temperature 73 73 0.22 73 0.42 73 1.05 73 1.33 Flocculant (Praestol) 50 50 50 50 50 Wash water Weight of dry 0): 92 ^ 0 5 2% 15th 60 60 Sludge ₃ .16H ₂ 90 BpO ₃ in the sludge of that 10 yield , 496. 200 Clear solution composition - Na ₂ O - (NH ₄ I ₂ O - HCl B ₂ O ₃ se CaO 80 MgO 59 * Borax (Na ₂ 0.2B ₂ O ₃ .10H ₂ 101 ülexite (Na ₂ 0 _# 2Ca0.5B-0 182 Dolomite (MgCO ₃ .CaCO ₃ ) 0.42 Silicic acid (SiO _? ) 1 0 0.30 0): 43ί MgCO ₃ :

209808/1727

The following examples show the results obtained according to the Great Cycle of Invention. The cycle of example 1 concerns the second crystallization of ammonium pentaborate, the cycle of Example 2 relates to the immediate crystallization τοη boric acid.

example 1

The system used corresponds to the scheme of Figure 1, v / o A, B, C, D, E and G mean:

A: the entirety of the column and filter of the soda factory B: reactor in which the piling liquid is mixed with sodium borate

is treated
C: Distillation column for desorbing most of the HH-

D: totality of crystallization, centrifugation and washing

of ammonium pentaborate
Ei device for the dissociation of ammonium pentaborate with

Production of B ₂ O, or boric acid G: absorber from the soda factory.

In B one introduces over 3 1 ton of pilter liquid from the following Composition:

Na ₂ O : 31 g / kg Settlement: (NH ^) ₂ O : 126 g / kg g / kg. HCl ί138 g / kg g / kg B ₂ O ₃ : : 73 g / kg g / kg co ₂ j . 53 g / kg H ₂ O ί ! 579 g / kg by 4,530 kg of borax of the following composition Na ₂ O j 162 B ₂ O ₅ ι 265 H ₂ O 473

The mixture brought to the boiling point releases a gas phase which contains:

(NH ₄ ) ₂ O: 36 kg

CO ₂ : 53 kg

and water vapor,

209808/1727

Some vapors are returned to the absorber G via 15. 1441 kg of the solution obtained are sent via line 0, where it undergoes a distillation, at a temperature of about 105 ⁰ C.
One takes from column G:

182 kg of steam via line 7 53 kg (NHiJpO via line 8. This ammonia is used for

Absorber G sent 1206 kg via line 10. This solution of the following composition;

: 97 fc / kg

_{4) 2} 0: 31 g / kg

HGl: 114 g / kg

B ₂ O ₅ : 221 g / kg

H ₂ O: 537 g / kg

is sent to D in a crystallizer maintained at about 15 G, wherein ammonium pentaborate crystallizes, which is separated from the mother liquor by centrifugation. In addition, 54 kg of water are introduced into D through line 16 to to wash the crystals on the slingshot.

At the outlet of the centrifuge you send: 940 kg mother liquor of the following composition to the absorber G:

Na ₂ O: 124 g / kg

(NH _{4) 2} 0: 9 g / kg

HGl ..: 147 g / kg '

B ₂ O ₃ : 78 g / kg

H ₂ O: 642 g / kg,

via 11 to dissociation device B for ammonium pentaborate 302 kg of ammonium pentaborate of the following composition

(NH ₄ ) ₂ O: 96 g / kg

B ₂ O ₃ ι 639 g / kg

H ₂ O: 265 g / kg

with 18 kg impregnation water.

In order to produce boric acid, the device B comprises a dissolving tank, a distiller column, a crystallizer, a centrifuge and a dryer.

209808/1727

Via 13, 52 kg of water are introduced into the centrifuge to wash the boric acid. Finally, * ± m is released from E 343 kg boi acid via 14 and 29 kg ammonia and water (in the form of * (NH ||) ₂ O) via 12. This ammonia is sent to the absorber G,

About 5 leave the absorber G 1111 kg of a solution of the following Composition:

Na ₂ O / 105 g / kg (NH.) ₂ O: 113 g / kg HCl: 124 g / kg B ₂ O ₃ : 66 g / kg

CO _9:; Aq g / kg H ₂ O "-y- : 544 g / kg This solution is sent to A in the brewing column of the soda factory, in which 122 kg of CO _{2 are} also introduced via 2.

You leave Tom Pilter

233 kg of sodium bicarbonate about 1000 kg of liquid over

This liquid is sent to B to be treated with a new batch of borax.

Example 2

Boric acid is immediately crystallized without ammonium pentaborate to go »

In the scheme of figure II, A, B, C and G denote the same apparatus as in Example 1. However, the distillation column C operates at 140 ⁰ O, D represents the entirety of the crystallization, centrifugation and washing of the boric acid »

The units A and B work under the same conditions as in Example 1. The solution is 6 liters too concentrated in BpO to enable the elimination in C of a sufficient amount of ammonia, as is the case with the crystallization in D of boric acid would be compatible «.

We therefore introduce into G:

1141 kg of a solution 1200 kg ΐ / ater durah

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The distillation column 0 operates at a temperature of One discharges from column C:

1316 kg of steam through 1238 kg of solution.

87 kg (NH ^) ₂ O through 8. This ammonia is sent back to the absorber G ·

Solution 10 of the following composition:

Na ₂ O: 95: g / kg

(M ₄ ) ₂ ©: 2.4 g / kg '

HGl: 111 g / kg

B ^ O ₅ : 215 g / kg

H ₂ O: 577 g / kg

is passed according to D into a ^{crystallizer kept at about 60 0} G, in which boric acid is crystallized, which is separated from the mother liquor and wash water by centrifugation.

60 kg of washing water are introduced in D through 13.

At the outlet of the centrifuge you send via 9 to the absorber 935 kg of mixed liquor with the composition:

Na ₂ O: 125 g / kg

(NH _{4) 2} 0: 3 g / kg

HGl: 148 g / kg

B ₂ O ₃ : 76 g / kg

H ₂ O: 646 g / kg

and gains over 11,343 kg of boric acid with 20 kg of impregnation water.

209808/1721

Claims (1)

-12 patent claims 1. Process for the production of sodium carbonate, boric acid and / or Boreatjri Hater starting from sodium borate in the Cycle of an ammonia soda factory, characterized in that one the "liquid from dtn filters of the soda factory with a Sodium borate reacts in such a way as to obtain: 1) a solution * which is essentially an ammonium borate, Contains sodium chloride and optionally ammonium chloride, 2) a gas phase, which contains ammonia, carbonic acid and water vapor, which is fed into the soda factory, where the solution 1) is heated and cooled one after the other, to result in: a) a solid crystallized phase on cooling, consisting of ammonium pentaborate and / or boric acid, the ammonium pentaborate then decomposing is used to release the ammonia it contains and to provide either boric acid or boron oxide, b) a liquid phase, formed in the mother liquors of the crystallization with a content of .Sodium chloride _# B ₂ O ₅ , a small amount of ammonia, which was initially in the solution Torhandtn, and possibly Amaonlumohlorld, β) tine gas phase, obtained when the solution is heated and / or in the decomposition of ammonium pentaborate Ammonia and vapor, before dit liquid b) and gaseous c) phase then in dit Sodafabrik gtltitet wtrAtn, * ■ in a way known to aioh Iittiu * t »iöarboiiat and tint tiittrflttssigktit su trhtlttn, vtltht »an. τοπ ηtue », as described by» btm, treated. 209808/1727 BATH 2, method according to claim 1, characterized in that the crystallization of the ammonium pentaborate and / or the boric acid is regulated in such a way that the mother liquors (solution ti) poured into the soda factory do not contain more than 78 g O «0» / kg, WWMWTDt The bio-carbonate column operates at about 30 o. 3. The method according to claim 2, characterized in that the crystallization of the ammonium pentaborate and / or the boric acid takes place at a temperature of at least equal to O ⁰ O · 4 · Method according to one of the preceding claims, d & duroh marked that the solution 1) a few * al 100 .g BgO ^ / kg contains «, and that from it the ammonia can be passed through a plate column is desorbed in countercurrent to the steam, which is created by this solution, and then you Aase it like that cools to crystallize boric acid au. 5. The method according to claims 1 to 3, iaduroh characterized ^ the solution 1) contains more than 100 g of B ₂ O, and that one! Part of the ammonia duroh Pass through> «a plate column in the counterflow, sum desorbed vapor, welpkev through the Solution is generated, and that one then «» cools it in order to obtain a 2wisehta ~ product which is Ammeniunjentaborat · 6. The method according to claim 5, characterized in that the ammonium pentaborate theraiaoh gwifohen 600 and 1000 ⁰ O is dissolved, to provide boron oxide and apntnitk tu. 7. Method according to claim 5, de ^ uroi * gekennitiohnet that the ammonium pentaborate is dissolved in a sufficient amount of water to obtain a solution which contains less than 100 g of B ₂ Oy /) cg , which then treats vegetables to claim 4. 8.Verfahren naoh one of the preceding claims, characterized marked, that a single quantity of pilter liquor is used sets in that there is an excess of ammonium luachloride on the sodium borate in the reaction gives " 9 "Method according to claim 8, because it is marked" ₉ the excess of Innonlumahl aric! ΐΩ? ί ti ha τ · Aav SiiHahi 209808/1727 BAD ORtQfNAL "~ 10 The method according to tinem dtr preceding claims, characterized marked, the * dl reaction between the filter liquid and atm sodium borate takes place under Sitdtn 11 ·. Ytrfahrtn naoh dtn Anaprüchtn 1-10, characterized because the sodium borate borax let " 12. The method naoh dtn claims 1-10, characterized in that daes daa sodium borate Tinoal let " 13 · Method according to Claim 12, characterized in that the Tinoal TQr implementing old filter fluid in is treated at well known whites, including him at CaHium and Magnesium in the clean and τοη etinen inert components too to free· 14. "Method according to claim 12, characterized in that one unmltttllia * dtn Tincal with dtr diluted filter liquid ums et, then that from the inert components of the Tinca existing bad "detach", and finally date the Solution Ton'üaloium and Magnesium cleans before putting them into the Soda factory works. 19. Proceed »make claim 13» daduroh marked that you immediately and ratch dtn Tinoal with dtr Filttrlüesigkeit converts, one can then separate the bad from the inert constituents of the lineal, and then the solution of paloium and Hagnteimm »efieit, eevör man ei · to the soda factory • ohiokt. 16, the method according to An · ρrueh 8, characterized in that one immediately ar dtn Tinoal with the liquid under Keep «· * Klaohuag boiling for a maximum of 15 minutes um8 «tit, dtni). Al · Sohlämmt from 4 · η inert components of the Tinoji separates the solution from calcium and Magnesium frees, 'bevoijman ei · echiokt in the soda factory. 17. ** ue commercial product, mämlioh sodium bicarbonate, Boric acid nmf boric oxide, obtained after a method of the preceding claims. 209809/1727 BATH ORIGINAL