DE459C - Process for the decomposition of ammoniacal distillation products from gas waters using Glauber's salt and chilli nitrate for the production of sulfuric and nitric ammonia, as well as soda - Google Patents

Description

1877.

G. TH. GERLACH in KALK at DEUTZ.

Process for the decomposition of ammoniacal distillation products from gas waters by Glauber's salt and chilli nitrate for the production of sulfuric acid and nitric acid ammonia,

as well as soda.

Patented in the German Empire on August 7, 1877. Longest duration: October 15, 1890.

As is well known, the production of soda by means of ammonia is based on the fact that when it is introduced of carbonic acid in a concentrate solution of table salt, which with caustic ammonia up to is saturated to a certain degree, bicarbonate of soda because of its lower level Solubility is eliminated, while ammonia remains in solution. The bicarbonate of soda After centrifugation and washing by calcining, it becomes simply carbonic acid Soda transferred; from the centrifuged solution, however, which, in addition to undecomposed Carbonate of ammonia and table salt, containing salmia, is made by distillation with the lime Caustic ammonia recovered and returned to the operation cycle.

Through experiments I have established that it is converted into bicarbonate of soda goes on with the same ease if one uses other sodium salts instead of table salt; this can be entirely explained by the solubility ratios of the double carbonic acid Natrons. In fact, concentrated Glauber's salt solutions and equally concentrated Chilli nitrate solutions, which are saturated with caustic ammonia to a certain extent are decomposed by the introduction of carbonic acid in such a way that double carbonic acid is formed Soda separates,. while in the solution alongside undecomposed carbonate of ammonia and undecomposed Glauber's salt or chilli nitrate, sulfuric acid ammonia or nitric acid ammonia are present. In all of these cases, implementation is only halfway done: only about halfway of the sodium salts used becomes even from very concentrated solutions in the form of bicarbonate of soda initially excreted. It should be noted, however, that through the excretion of bicarbonate of soda, the specific gravity of the Lyes are very reduced, and just as when using table salt the remaining, Solution containing ammonia is still able to dissolve considerable quantities of table salt anew, so the solutions obtained here can still absorb Glauber's salt or chilli nitrate; if, therefore, an excess of these salts is added, the introduction is continued of carbonic acid the conversion of table salt, Glauber's salt or chilli nitrate into salmiak, sulfuric acid ammonia or nitric acid ammonia can be reached much more completely. In the ammonia-soda process, this is cooked. salt therefore as so-called »correction salt« added to the lye, and it serves to keep the solution always in a saturated state. In this way you got there, probably three quarters of the table salt used in Transfer soda.

Namely the behavior of sulfuric acid It is natrons that I have used, from the ammo niacal distillation products of the Gas water to produce sulfuric acid ammonia with the simultaneous production of soda, while the ammoniacal distillation products, which are produced in the distillation of gaseous waters, or in bone distilleries, or in coke distilleries, until now in the following Way to be processed:

In order to produce ammonia or caustic ammonia, the gas water is mixed with caustic lime distilled; in order to obtain carbonate of ammonia, the dry ammonia gases are used carbonated.

The ammoniacal distillation products are used to produce sulfuric acid ammonia in sulfuric acid, or they are decomposed by Gyps to sulfuric acid To form ammonia.

Salmiak is prepared through Introducing the cooled ammoniacal distillation products in hydrochloric acid or through They decompose by means of alkalis containing earth chlorides or metal chlorides (e.g. Calcium chloride or manganese dioxide.

About the implementation of the ammoniacal distillation products; medium Rock salt, sea salt or salt pools.

I make a concentrate solution of carbonate of ammonia by distillation of

Gas water and dissolve salt or chlorine in it! sodium in the proportion that at least ι Aeq. Sodium chloride to ι Aeq. carbonate of ammonia in the most concentrated form. Solution is included. Such a solution has 1.22 spec. Weight. In this solution will carbonic acid introduced as long as bicarbonate of soda still falls out. Here hydrogen sulphide escapes, which is always present as ammonium sulphide in the distillate of the gas water is included. When the gas water is distilled with lime, a sulfur-free one is obtained Distillation product, but using this caustic ammonia are later 2 Aeq .. Carbonic acid required for the precipitation of sodium bicarbonate.

The bicarbonate of soda obtained is separated from the liquid, either by Centrifuges or displacement apparatus.

The washed out bicarbonate of soda is heated to the second equivalent of carbonic acid to drive it out, or it is boiled for the same purpose with as much water as one concentrate soda solution, which is brought to crystallization. The escaping Carbonic acid can be used to decompose new quantities of lye.

The liquid which in centrifugation contains ammonia, undecomposed sodium chloride and carbonate of ammonia small amounts of dissolved sodium bicarbonate. To get the carbonic acid ammonia again To obtain it, it is distilled off, and from the liquid, which is now only salmiac and sodium chloride, salmiak is obtained by crystallization after the largest Part of the sodium chloride has been eliminated from the hot liquor by concentration; or one uses the liquid for distillation with lime to produce ammonia.

All undecomposed sodium chlorine is returned to the operating cycle.

Differences between imeinem process and the ammonia-soda process. My process differs from the ammonia-soda process in the following ways:

1. I aim to make the best possible use of the gas water and always bring new quantities of gas water for use. The ammonia-soda process, however, aims only the production of soda and always returns the ammonia used as caustic ammonia into the cycle of operations.

2. The ammonia, which is obtained from the gas water by decomposition with table salt, is obtained by crystallization according to my method, it is not decomposed by lime and is not reintroduced into the cycle of operations as caustic ammonia. Therefore, there is also no loss of ammonia through volatilization.

3. So I do not need to use lime, with the exception of the small amounts, which in the distillation of the gas water are necessary for the decomposition of the non-volatile ammonia compounds in gas water.

4. No table salt is lost, but it returns to the cycle of operations. That's why I get an equivalent for each applied sodium chloride a full equivalent of soda, as a by-product, while in the case of the ammonia-soda process, this has not yet been achieved.

5. The carbonic acid, which is contained in the gas water, comes as carbonic acid ammonia for use, while in the ammonia-soda process caustic ammonia - or salmiac, decomposes by lime - is used.

6. Apart from the gas-water distilled off, no by-product is obtained which is considered unusable would have to be removed.

7. The costs for the recovery of the ammonia are saved because the ammonia contains Lye only needs to be evaporated a little to obtain salmiac through crystallization.

8. By always bringing new quantities of gas water for processing, saI-miakproduction works steadily advancing, as is the extraction of soda as a by-product.

There can no longer be any doubt that the ammonia-soda process increased one Will become widespread and increasingly important in the soda industry; nevertheless it remains true that its implementation involves certain difficulties is.

The evils which practitioners criticize in the ammonia-soda process are as follows:

1. The great quantities of lye which one has to deal with.

2. The great consumption of coal which occurs in the constant recovery of the ammonia is required.

3. The inevitable loss of ammonia, mainly due to volatility of caustic ammonia is caused.

All these inconveniences have been eliminated in my procedure:

1. The alkalis are evaporated to obtain the salmiaks, and this salt is crystallized even with a low concentration.

2. The recovery of caustic ammonia with lime is omitted, and therefore also takes place the aforementioned large consumption of coal does not take place.

3. The loss of caustic ammonia is out of the question as there is no caustic ammonia occurs in this process, but only salmiak,

By means of the conversion of the ammonical distillation products

Glauber's salt or sodium sulfate.
I represent a concentrate solution of carbonate of ammonia, such as is obtained in a known way by distilling gas water. In this I dissolve crystallized Glauber's salt

without any further addition of water; or I dissolve the anhydrous sulfate, how to do such obtained in the manufacture of hydrochloric acid or nitric acid, in a less concentrated solution of carbonate of ammonia. This saturated solution should also be based on ι Aeq. carbonic acid Ammonia ι aeq. contain sodium sulphate; she has the spec. Weight 1.30. In these concentrated solution, carbonic acid is conducted as long as bicarbonate of soda is still precipitating ; the bicarb onate is then separated from the lye and converted into soda.

The lye, which was separated from the bicarbonate, contains sulfuric acid ammonia, undecomposed Sodium sulphate and carbonate of ammonia together with small amounts of dissolved double carbonate Baking soda. The carbonic acid ammonia is recovered by distillation and returns to the cycle of operations.

From the lye, which now consists only of ammonia sulphate and sodium sulphate contains, the sulfuric acid ammonia is separated from the sulfuric acid soda; the sulfuric acid Baking soda returns to the cycle of operations.

About the implementation of the ammoniacal distillation products by means of

.Chilis nitrate.

I prepare a concentrated solution which has equal equivalents of carbonate of ammonia and sodium nitric acid. Such a solution has 1.37 spec. Weight. In this solution carbonic acid is conducted as long as bicarbonate of soda falls out.

The process is exactly the same as with sodium chloride and sodium sulphate. The end products are nitric ammonia and soda.

In all these cases, the cooled gases from a coke fire can be used as carbonic acid or come from a lime kiln; or you can get carbonated can also be produced in a purer state if one uses the cooled fireplace gases or the Gases from a coke oven or a lime oven into a saturated solution of soda pumps. Here the carbonic acid is absorbed, bicarbonate of soda falls out, while the atmospheric air and nitrogen escape. Then the lye is heated together to the precipitated bicarbonate of soda, the latter salt gives the second equivalent Carbonic acid. In this way you work with less lye than with the well-known Ozoufschen Procedure.

For the decomposition of the ammoniacal distillation products by the alkali salts mentioned the same apparatuses are used as they have been in the ammonia-soda process ever since as the most expedient.

Up to now table salt has been used exclusively in this way in industry, but only to make S o da; Until now it had not been recognized that this process could be extended extremely advantageously to the processing of gas water for the production of salmiac. Up to now, gas-water has never been processed in such a way that ammonia and soda are obtained at the same time, and no practical proposal has ever been made to obtain ammonia sulphate or ammonia nitric acid from the gas-water at the same time as soda this happens after my procedure. As will be seen at first glance, this method offers advantages aufserordentliche against the ordinary type ¹ processing with acids.

Against a relatively small outlay for wages and equipment, the costs are the acids are considerably reduced by the much cheaper alkali salts, with the soda for the soda is processed almost free of charge. An advantage that should not be underestimated it is also that the ammonia salts obtained in this way are beautifully white because they are through Crystallization can be obtained.

For comparison, I present a calculation on the production of sulfuric acid ammonia according to the old and new procedure here next to each other.

Production costs of 1000 ctr. sulfuric acid ammonia.

According to the old procedure. 1000 ctr. Sulfuric acid of 60 ⁰ B

to 4 M 4000 M.

In addition all other business expenses.

Proceeds:
1000 ctr. sulfuric acid ammonia

to 19 M. 19000 M.

According to the new procedure. 1076 ctr. Sodium sulfate anhydrous

to 2 M. . 2152 M.

For this all other business expenses as above;

furthermore interest and depreciation of the new plants, increased wages, manufacturing of carbonic acid and others

Additional expenses 6000 M.

Total . 8152 M. proceeds:
1000 ctr. sulfuric acid ammonia

for 19 M 19000 M.

803 ctr. calcined soda or 2165 ctr. crystallized soda. . . looooM.

Total . 29000 M.

If the sodium sulfate used is 10 pCt. free acid contained:

1000 ctr. ammonia sulfuric acid and only

723 ctr. calcined soda or 1949 ctr. crystallized soda. I still have to mention how the centrifuged liquor is treated further. First

jyjc the undecomposed carbonic acid ammonia dqrph distillation · recovered; here too, the small one settles down. Amount of dissolved double carbonate of soda with the existing Salmia or sulfuric acid ammonia, in which carbonate of ammonia escapes and table salt or Glauber's salt is obtained.

About the separation of ammonia and table salt.

If you steam such a solution, which contains approximately equal amounts of ammonia and table salt, as far as the salt skin and if you let it crystallize, salmiak is crooked, but of course he falls asleep the more table salt, the more abundantly the mother liquor contains it. You vape on the other hand, the solution continues to enter, even after a skin of salt forms in the heat, so it falls salt out of the boiling solution and the solution is enriched with ammonia.

The precipitated table salt always contains ammonia from adhering mother liquor and in this state it is again filled with new quantities of the ammoniacal product of the distillation brought together to be decomposed by carbonic acid.

In order to achieve this enrichment of the alkaline solution in salmiak as completely as possible, and to achieve this To remove table salt as much as possible, I carried out a systematic evaporation in such a way that that I set up four boilers I to IV side by side, but only one boiler, for example the one at the extreme left end (IV) was refilled with the lye to be evaporated.

IV
U

III

II

It was only from this cauldron that the precipitated table salt was scooped up while the table salt that precipitated in boiler III was brought to IV, that of II after III, that from I to II.

On the other hand, lye was only used from boiler I alone, while the lye was taken out Kessel II was brought to Kessel I, from III to II and from IV to III.

So while the precipitated salt back laid off from right to left, got the liquor, which at Salmiak _to: enriched, from left to right.

All boilers were always kept full during the evaporation process, whatever in factory operations can best be achieved through communicating tubes.

The boiling points of the boiler liquor I and II were ii6 °, the boiler 112 ⁰ III and IV of the boiler io8 °.

In order to remove all common salt as much as possible, the ammonia solution in kettle I was so concentrated that that on cooling it solidified to a crystalline paste; therefore so much water was added again that the Heat only began to form a salt membrane. The salmiak obtained in this way by crystallization gave only a residue of 1.75 pCt when glowing. Table salt.

On the separation of ammonia sulphate and soda sulphate.

From a solution containing approximately equal equivalents of ammonia and sulfuric acid Contains baking soda, crystallizes a double salt on cooling according to the formula:

JVH., NaSO, .H ₂ O.

This salt contains:

Sodium sulfate. -.
Ammonium sulfate
water

crystallized
45.81
42.58

anhydrous 51.82
48.18

100.00 100.00

However, if such a solution continues to evaporate during boiling, anhydrous Glauber's salt separates out and sulfuric acid ammonia remains in solution.

It is a well-known fact that double salts exist only in crystallized states. When the solutions are evaporated, all the double salts decompose in such a way that it is difficult to do so soluble salt separates and the more soluble salt goes into solution. About the type of Separation of the two salts mentioned I have nothing more to say than the separation is carried out exactly as it was done with salmiak and table salt.

The boiling points of the solution of the boiler I and II were 111 °, the boiler III iio ° and of boiler IV io6 °.

The excreted anhydrous Glauber's salt contained about 20 pCt. sulfuric acid ammonia and, together with new portions of Glauber's salt, came to further decompose the ammoniacal Distillation products.

A little double salt crystallized out of the lye in kettle I when it cooled but cold mother liquor on further evaporation yielded a beautiful, white, crystallized one sulfuric acid ammonia, which is only 1.8 pCt. Contained Glauber's salt.

This very satisfactory result proves that the chosen one. Way to separation the salt is quite the right one.

Finally I should like to remark that this happens when table salt or water-free salt is eliminated Glauber's salt lightly burn the salts in the boiling heat; So you have to work in a factory Evaporate with pressurized steam in boilers with double walls and also for acceleration Insert steam coils, preferably made of cast iron, since the coils are made of lead, at least in salmiak production to be attacked.