SU48227A1 - The method of separation of iodine from the drilling waters - Google Patents

Description

Iodine is adsorbed from drilling waters by activated carbon, the effect of which is the more effective the cleaner the feedstock (drill water) is from mechanical impurities and various precipitates that fall out of the water during the reactions of water iodide oxidation.

Since the oxidation of iodides to elemental iodine occurs in an acidic medium and acidification is carried out with strong technical sulfuric acid in water, calcium is converted into gypsum during acidification reactions.

The resulting gypsum has a very fine-crystalline structure and, the passage with acidified water through the layer of activated carbon, clogs its pores, thereby reducing its activity to adsorption FROM 40-50%, which accordingly causes an extremely rapid aging of the fresh adsorbent with associated carburization of coal, which also reduces the effect of his work.

At the same time, gypsum also has a detrimental effect on the washing of iodine from coal, since it clogs the pores of the coal that has already adsorbed iodine, but especially the negative effect of gypsum occurs during the regeneration of the coal coming out of the adsorption process in the waste coal activation furnace. Here, the presence of gypsum not only leads to additional waste of heat and heat to restore the activity of coal, but also results, during calcination, to waste coal, which is coupled with the reaction of calcium sulphate reduction to sulfide, according to the equation

CaSO -f 4C - CaS + 4CO

Only if calcium sulphate is reduced to sulphide, which is subsequently dissolved in HC1, is it possible to regenerate coal, which was used even on waters containing copious amounts of Ca.

All these defects can easily be eliminated by using HjSOi HCL instead of HL However, the economy of this replacement is losing much due to almost twice as much more expensive (equivalent) technical hydrochloric acid. The issue is complicated - still not transportable with hydrochloric acid because of its transportation in glass containers.

All this makes us refuse to work with HC1, although the expediency of its use is obvious and proven.

The component of the present author's testimony is that hydrochloric acid can be obtained here from iodine factories from drilling waters, and for such an installation costs are required that pay back extremely quickly.

The principle of this method is based precisely on the formation of gypsum when HaSO is added to drilling waters containing large amounts of Ca.

 The fact is that in water Sa is

in the form of CAL = so when adding

 the reaction goes to form

CaCl24-H2SO4- CaSO4H-2HCl, and the resulting gypsum leaves the sphere of reaction.

The resulting hydrochloric acid is weak and goes to the process of acidification instead of sulfuric.

The preparation of this HC1 is as follows. Strong H2SO4 is added to a certain volume of working water in amounts equivalent to Ca, i.e. able to bind all Ca into gypsum. This operation is carried out in a gummed vat equipped with a cone for sludge-forming gypsum.

After 8 hours, all the gypsum settles to the bottom in the form of a crystalline mass, easily removed from the cone by a simple drain. The solution is completely clarified.

After this, the solution is decanted through a valve above the cone, and, as a precaution, it is even better to filter this solution through a filter of acid-resistant tiles. The filtration rate of the solution is very high, as usually settling gives, as indicated, a clear solution.

After draining and (if necessary) filtering, this solution enters the same gum tank adapted for dosing of the HC1 obtained during the acidification process instead of H2SO4.

Since the content of Ca in water reaches a rather large (up to 10%) value, and acidification leads to weak acidity, it is possible to acidify up to 70 volumes of working water with a single volume of prepared HC1. When acidified with this HCI solution, gypsum formation is completely eliminated and activated carbon after a monthly period of work remains slightly different from fresh in appearance.

Coal saturation almost doubles (instead of 19% of the limit for S5% plastered coals when working with this HC1), which accordingly reduces the consumption of coal.

When regenerating (reactivating) the activated carbon that worked with this acid, its loss is reduced to a minimum, and even the coal itself does not need to be regenerated for a long time, and after removing iodine from it, it can be repeatedly used again for iodine adsorption.

This method solves the problem of very cheap development of ioniferous waters containing Ca, and can be recommended where the use of HgSO, similar to iodine production, leads to a difficult process, namely the formation of insoluble sulfates.

The cost of HC1 obtained is equal only to the cost equivalent to H2SO4 consumed, i.e., the process is not expensive, since iodine contained in the drilling water left for HC1 preparation enters the total flow along with iodine of water which is acidified with this solution.

The subject matter of the invention.

A method of separating iodine from drilling waters containing alkaline earth metal chlorides by treating these waters with acid and adsorbing iodine with activated carbon, characterized in that only a portion of the drilling water is treated with sulfuric acid to form free sulphates from chlorides. alkaline earth metals are separated, and hydrochloric acid solution is used to acidify the rest of the treated water.