SU952734A1 - Process for purifying sodium chloride brine from calcium ions - Google Patents

Description

(54) METHOD FOR CLEANING OF A SODIUM SODIUM CHLORIDE FROM CALCIUM IONS

This invention relates to the technology of deep purification of sodium chloride brines from calcium ions, which makes it possible to obtain brines that are suitable for electrolysis with an ion exchange membrane or used to obtain high frequency sodium chloride.

A known method for the purification of sodium chloride brine from calcium ions, including the treatment of brine with sodium monohydroorthophosphate fl.

The disadvantage of this method is the impossibility of obtaining sufficiently: a high degree of purification of sodium chloride from calcium ions.

The closest technical solution is a method for purifying sodium chloride brine from calcium ions, including treating the brine with orthophosphates of alkali metal in an alkaline medium at a pH of more than 10 E23.

The disadvantage of this method is the low degree of purification of the brine from calcium ions, since their content in the purified brine is 1-4 mg / l. Furthermore, this method is effective only with a high content of calcium ions in brine (on the order of 20-211 mg / l).

When the content of calcium ions is 810 mg / l, this purification method is ineffective and long-lasting, which will decrease its use in industrial conditions.

The aim of the invention is to increase the brine purification rate and reduce the duration of the process.

The goal is achieved by

10 that sodium chloride brine is treated in alkaline medium with an alkali metal orthophosphate in the presence of a mixed salt of monohydroxo orthophosphate and calcium orthophosphate calcium.

15

In this case, the mixed salt is introduced into the initial brine in the amount of 100,200 mg / l in terms of calcium ions.

The amount of mixed salt injected less than 100 mg / l does not have a significant effect on increasing the extent of brine purification from calcium ions; when a mixed salt is introduced in an amount greater than 200 mg / l, it does not affect the acceleration of the process.

25 increases the degree of purification and increases the amount of slag formed.

Example 1. In 1 liter of brine containing 300 g / l of sodium chloride,

Claims (2)

30 injected with 2 ml of a sodium orthophosphate solution with an ion concentration of 25 g., 5 ml of a solution containing 78.8 g / g of sodium hydroxide, and a suspension of a mixed salt of monohydroxyphosphate and calcium orthophosphate containing 1250 mg / l of SauSON) (PO.), Where n is 6-12 j, which is 100 mg / in terms of calcium ions. Semi | Chenny suspension is stirred for 10 minutes. The precipitate is separated from the brine on a dense paper filter and the calcium ions in the filtrate are determined by extraction-photometric method using Azo-azo-Oxy-BN. In the filtrate, 0.14 mg / l of 60 mg / l of NaOH and 108 mg / l was detected. Example 2. The experiment was carried out as in Example 1, the amount of the mixed salt added was 200 mg / l in terms of calcium ions. The contained filtrate ion is 0.14 mg / l. . PRI me R 3. The experiment was carried out according to example, L, the amount of the mixed AALOK salt introduced was 150 mg / l in terms of & calcium ions, calcium ion content in filtrate 0, l, 4 - nfr / n ,. Etc. l MER 4. In 1 l of brine containing 300 g / l of sodium chloride and 1.6 mg / l, 2 ml of a solution of OE phosphate of sodium containing 47.25 g / l (PQ ions n 1.5 ml of solution) are injected, containing 78.8 g / l of hydroxy and sodium. The brine is stirred at and the resulting suspension is filtered on a dense filter paper. The filtrate is found after 0.5 h. mixing 1.2 mg / l Ca, 60 mg / l NaOH and 134 mg / l PO, after 1 h stirring 1.12 mg / l Ca after 2 h stirring 1.10 mg / l after 5 h stirring 1.05 mg / l Thus, the proposed method, compared with the known, allows the soil to 10 times increased The degree of purification of the brine from calcium ions (1.12 mg / l to 0.14 mg / l) and significantly reduce the duration of the purification process (from 14 to 10 min). Claim 1. The method of purification of sodium chloride brine from calcium ions, including treatment of the brine in an alkaline medium with an alkali metal orthophosphate, characterized in that, in order to increase the degree of purification of the brine and reduce the duration of the process, the brine is processed in the presence of a mixed salt of monohydroxo orthophosphate and calcium orthophosphate 2. The method according to claim 1, is also distinguished by the fact that the mixed: this salt is introduced into the initial brine in the amount of 100-200 mg / l in terms of calcium ions. Sources of information taken into account during the examination 1. Furman A.A., Yraibman S.S. Cooking and. brine purification, chemistry, 1966, p. 59. 2. The patent of Germany 2837192, cl. C 01 D 3/16, 1979 (prototype).