SU21130A1 - The method of pre-cleaning salt brine for the ammonia-soda process - Google Patents

Description

The present invention relates to methods for pre-purification of saline brine from calcium and magnesium salts by adding ammonia and carbon dioxide in quantities insufficient to complete the ammonia-soda process, after passing the solution through the filter air cleaner and the column air washer.

As is known, the initial raw material of ammonia soda plants — natural salt brines — contains significant amounts of calcium salts and rotten and very small amounts of iron and aluminum salts. When ammonia is introduced into the brine with a certain amount of carbon dioxide (absorption process), Ca, Md, Fe.A compounds precipitate from the brine in the form of carbonate salts of basic carbonate salts and hydrates. This precipitate of salts must be completely removed from the brine, so it will clog up all subsequent apparatuses and, moreover, 3 a5 will contaminate soda. Usually, in the Solvay system soda plants, precipitated calcium and magnesium compounds are separated by settling at jie. transmitting a hot salt-ammonia solution through the battery er

tical iron clarifiers (dosing), equipped with agitators. Periodically, these sediments are transferred to a special, settling tank (decanter), where they are defended from the solution, washed several times with decantation and pumped into the distillate of the distillate to the distiller for final separation of the assimac precipitate. When, with respect to the order of release, the specified precipitate from ammonia-saline solutions is resorted to one or another of the following methods: a) allow the solution to stand on the dosage after the complete amount of ampiacum is introduced into it, i.e.: 75-85 ammonia per liter | b) directing the solution to the dosers only after the first absorption phase, i.e. after the introduction, about half of the ammonia, namely, “per liter and c) combine the first and second variants. However, all these methods of operation have the following disadvantages: 1) the device - absorber is gradually contaminated by precipitation, as a result of which it is necessary (periodically every 2 months) to be shut down and put in for cleaning; 2) due to the high content of NHs in the salt-ammonia solution, there are losses of NBs

the selection of tricycles in dispensers; 3) in addition. High NHs content in them is necessary (even after washing) to start up the distilller and thereby accelerate the clogging of the latter, i.e. reduce the period of his work and, finally, 4) Purification of brine oy magnesium and calcium, is not enough

complete; - i-L .-; .. /

Similarly, the method of preliminary (before absorption) purification of brines from the calcium and magnesium salts contained in them has hitherto been sufficiently satisfactory to solve the problem of brines cleaning, since in order to achieve quite satisfactory results, this method requires adherence to the well-known 6-1 in relation to the temperature of the process, and in relation to the amount of carbon and the type of carbon dioxide introduced into the brine.

In order to obtain the maximum degree of purification of the brine from calcium and magnesium salts, the inventor introduces g of carbon dioxide per liter of solution into solution F-8 with simultaneous or subsequent heating of the brine to 60-70 °. After these operations, the solution is sent to the dosers, where it releases up to 98% of its calcium and magnesium salts. The introduction of the required amount of carbon dioxide into the skin solution can be realized by the absorption of gaseous carbon dioxide by dissolving sodium cibiporo bicarbonate.

To do this, the solution that passed the air washer of the filtration column gas washer is passed through a bubbling, cassette-equipped apparatus through which the carbon dioxide-rich drying gas (90% COz) blown through the nodder scrubber is blown through with a pump.

The carbon dioxide not absorbed in the bubbling apparatus is returned again to the suction tube scrubber. With this method, neither ammonia nor carboxylic acid is lost during this operation. Solution after

the introduction of carbon dioxide into it is heated to C.

The same carbon dioxide content is obtained by passing a solution of past-washer air filters and gas columns through the apparatus, which is a closed tank equipped with a stirrer, in which the necessary amount of raw bicarbonate is continuously and automatically added as it comes from the vacuum. filter.

In the same Apparatus, the fluid is also heated up to BWC or with the heat of the exhaust steam, or by heat exchange with liquids to be cooled (hot metering liquid, hot liquid from the absorber, steam from the exeptrum, hot water from the refrigerators; columns, etc.). Subsequently, to separate the precipitates from the brine, the latter is passed through the usual: system:: dosing units. The precipitate collected in the canter, after washing it with fresh brine, is discharged into the sewage system, and the washing brine is fed to the abs.

The subject of art.

1. A method for pre-purification of salt brine DAmAmI; ChNR-Sodovrgr from Calcium and Magnesium; and washer; gas columns, characterized in that the carbon dioxide is injected in an amount of about; t, 4 to 8 per liter of brine from a single heating followed by heating to 60-70 °, after which the formed, The precipitate is separated by 1).

2. Receive a lift. Referring to clause 1, it should be noted that carbon dioxide is introduced into the bath, in the form of sodium boron sodium. ,