SU788629A1 - Method of producing carnallite - Google Patents

Description

The invention relates to methods for producing artificial carnallite and can be used in the processing of polymineral potash, natural carnallite and chlorine magnesium solutions.

A known method for the production of carnallite, including the interaction of a chloromagnesium solution with potassium chloride and the subsequent isolation of the resulting suspension of the product by vacuum crystallization.

The disadvantage of this method is to obtain a comparative methycrystalline and highly aggregated product, which, after 4 filtration or centrifugation, has the same content of mother liquor with impurities of sulphates and calcium chlorides and other salts that contaminate

carnallite, which degrades its quality. Also, when using from

of the known method, the intensive formation of salt outgrowths (inlays) occurs, to remove

the devices often have to be stopped (after 3-5 days) for industrial purposes, to with which, their efficiency is reduced.

The purpose of the invention is to increase the size of the product crystals and the elimination of hardware incrustation.

The goal is achieved by the described method, including the interaction of a chlorine-magnesium solution, previously mixed with a suspension of carnallite in a ratio of 1: (100-200), with potassium chloride and the subsequent separation from the resulting suspension of the product by vacuum crystallization at a ratio of the circulation of the suspension equal to

8-38, and the interaction time

and the duration of the crystallization cycle is maintained within 30120 s at a concentration of the solid phase, respectively, 50–20 ms,%.

The proposed method allows to significantly increase the size of carnallite crystals and reduce interwash run-machines,

Comparative data with a known method on the achieved effect are presented in table, 1.

The proposed intervals of technological parameters of the mode of carnallite production create the necessary conditions for carrying out the processes of conversion and crystallization in the metastable supersaturation of the solution in which mainly crystal growth takes place, and the emergence of new embryos and their growth with the formation of aggregates sharply reduces. This provides an increase in the quality of the product due to the production of large crystals with a low degree of aggregation and a low residual content of m & t solution, contaminated with impurities. Under these conditions, the formation of incrustations is also eliminated, which makes it possible to increase the interwash period of the apparatus,

In tab. Table 2 shows data on the effect of the amount of carnallite suspension (degree of mixing of chlorine solution with carnallite suspension before carnallite conversion) introduced at the stage of conversion on the quality (size, aggregation and humidity) of production crystals.

As can be seen from the table. 2 preliminary mixing of the starting chloromagnesium solution with carnallite suspension should be carried out in a ratio of 1: (100-200), since it is in this interval that production carnallite of better quality is obtained, having a coarse crystal size of more than 0.5 mm and a moisture content of 3-4 % in accordance with the requirements of the technological regula tion. Table 3 shows the averaged results of laboratory experiments to study changes in the quality of the product depending on the circulation ratio of the suspension (raster supersaturation) pr carnallite crystallization,

Example 1, a chloromagnesium solution containing 32–38 May,%, in an amount of 73.6 tons is mixed with 7360 tons (in a ratio of 1: 100 carnallite suspensions. 110.4 tons of potassium chloride suspension prepared from 11.4 KC1 crystals and 99.0 tons of the mother liquor obtained after crystallization of carnalite. Then, a conversion of chlorine magnesium solution and potassium chloride suspension with a duration of 120 s is carried out in a circulation apparatus. Thus, 7544 tons of carnallite crystal suspension are obtained. sent to the stage see Chlorine solution with chlorine solution, and 184 tons of suspension containing 35 tons of carnallite crystals and 149 tons of solution are sent to the crystallization stage by cooling under vacuum to a final temperature of 40 ° C. The crystallization process is carried out in a three-unit vacuum unit with the release of carnallite crystals in an amount of 5, 0 tons in the first case, 4.35 tons in the second case, and 4.0 tons in the third case, and 1.6 and 2.4 tons of water, respectively, by evaporation. In each installation case, the process is carried out with circulation of 1000–1600 m / h carnallite suspension at a frequency of 8-12 and ontsentratsii solids 40 wt%. The duration of the crystallization process in one suspension circulation cycle was 45 seconds. From 176 tons of carlitite suspension, 50 tons of carnallite crystals (based on the dry product) are filtered out and 126 tons of mother liquor are obtained, 99 tons of which are fed to prepare a suspension of potassium chloride, 37 tons are sent for further processing.

Example 2. A chloromagnesium solution, having a MgCl + CaCl content of 32–38 wt.% In an amount of 73.6 tons, is mixed with 14,720 tons (i = 1: 200) of carnallite suspensions. 110.4 tons of suspension are introduced into the mixture potassium chloride prepared from 11.4 tons of KC1 crystals and 99 tons of the mother liquor obtained after crystallization of carnallite. In the process of conversion of KC1 and MgClj, 14,904 tons of carnallite suspension are obtained. A part of this suspension in the amount of 14,720 tons is returned to the stage of mixing with chlormagt.

184 tons of the suspension is directed to a vacuum crystallization, which is carried out analogously to Example 1. 50 tons of carnallite crystals are obtained.

When described in examples 1. and 2 modes of implementation of the method, the average size of carnallite crystals was 0.5-0.6 mm, and the sulfate ion content did not exceed 0.054 wt.%. The product is fully meet the requirements of process regulations and standards.

Table I

The average diameter of the crystals of artificial carnallite, mm Content of impurities in production crystals, carnallite,%: - - Chloromagnesium mixture. Product quality with roll coating in

1:50 I 1: 100 | 1: 150 1: 200 | 1: 0.31 0.52 0.58 0.55 0.40

93 30533 6-8 4-53-44-55-6 0.25-0.35 0.45-0.60

Table 2

300

0.55 Not less than 0.5 mm of solution with a ratio

Average size of crystals, mm0,55

| Lgregirovannost crystals,% O

The content of the mother liquor in terms of the humidity of the crystals after filtration,% 4

T ablitsa

0.58 0.56 0.45 0.38 0.33 312567592

3-4 3-4

five-

7-8

Claims (2)

<claim-text> 1. The METHOD of OBTAINING KARNALLITE, including the interaction of chlorine magnesium solution with potassium chloride and the subsequent separation of the product vacuum from the resulting suspension - </ claim-text> </ li> </ ul> <ul style = "list-style: none;"> <li> <claim-text> 2 crystallization, characterized in that, in order to increase the size of carnality crystals and eliminate hardware incrustation, a pre-chlorine magnesium solution is mixed with the suspension in a ratio of 1: (100-200), and the product is evacuated by vacuum crystallisation at a rate of circulation of suspension equal to 8-38. </ claim-text> </ li> </ ul> <ul style = "list-style: none;"> <li> <claim-text> 2, Method pop. 1, characterized in that, with the interaction time and the duration of the crystallization cycle, it is maintained within .30-120 s with a concentration of the solid phase, respectively, 50-20 wt.%. with </ claim-text> </ li> </ ul>