SU998346A1 - Process or preparing solution of sodium chloride - Google Patents

Description

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The invention relates to a method for preparing a sodium chloride solution used in the chlorine industry as an aiolite.

The closest in technical essence and the achieved result to the proposed is a method of preparing a solution of sodium chloride, consisting of three stages, i.e. the preparation of Oiiporo brine by dissolving the salts of natural deposits or secondary technological raw material, preparing a reverse brine by dissolving the salt obtained after electro-alkali residues, and joint reagent purification of the raw and reverse brine followed by precipitation of impurities. Cooking the solutions are carried out in capacitive apparatuses with agitators or bubblers when moved for 4-6 hours or in apparatus operating on the principle of airlift. After brine and soda treatment of the brine with calcium and magnesium salts, the brine is cleaned in a fluidized bed clarifier (with an average clarification rate of 3-5 m / h) 11.

The disadvantages of this method are the low specific productivity, the duration of the process, the impossibility of obtaining brines containing sodium chloride above 310-315 g / l and the content of calcium and magnesium impurities after clarification above 15-30 mg / l.

The aim of the invention is to increase the rate of dissolution of sodium chloride, to obtain a solution supersaturated with sodium chloride, to increase the rate of precipitation of calcium and magnesium impurities and to reduce their content in the solution after precipitation.

The goal is achieved by the fact that according to the method, the pulp is processed in a magnetic field before dissolving 5, and the dissolution is carried out in a pulsating mode, and the pulp is processed in a magnetic field of 150-2000 E at a feed rate of 0.7-1.0 m / s and dissolving in

20 pulsation mode is carried out at a pulsation intensity of 6000-8000 mm / min.

It is advisable to treat the water before mixing with sodium chloride.

in a magnetic field of 1500-2000 Oe at a feed rate of 0.7-1.0 m / s.

The use of the pulsation dissolving regime at the pulsation intensity of 600–8000 mm / min allows obtaining solutions with a content of 315 g / l of sodium chloride at a pulp processing time of 1.5–2.0 minutes An increase in the pulsation time to 30–40 min leads to an increase in the concentration of the solution by 3–4 g / l. When the intensity of the pulsation decreases below 6000 mm / min, the rate of salt dissolution decreases and the residence time of the solution in the pulsation zone increases to achieve the same dissolution effect to 6-8 missions. Increased ripple intensity is higher. 8000 mm / min leads to the uios of the pulsation apparatus.

The use of water treated in a magnetic field of 1500–2000 Å strength at a feed rate of 0.7–1.0 m / s makes it possible to obtain solutions with a content of 240 g / l of sodium chloride at 2 min stirring, at 8–10 min 316 g / l, 50-60 min - 322 g / l, which is the limit of solubility at the temperature of the experiment.

The magnetization efficiency is about the same when the velocity of the solution passes through a magnetic field, in the ranges of 0.7-1.0 m / s and 2.8-3.1 m / s and the intensity of the magnetic field is 1500-2000 Oe and 3200-3500 Oe In the proposed method, a mode of 0.7–1.0 m / s and 1500–2000 Oe was chosen, based on the equipment possibilities and for the purpose of economizing energy costs.

The table shows the results of obtaining solutions of sodium chloride using the proposed method, which show that with optimal modes of joint action of pulsation and magnetic treatment on sodium chloride pulp with a contact time of up to 2 minutes, solutions with a concentration higher than the solubility limit (325 g / l) are obtained, cannot be achieved by applying pulsation and magnetic field separately. The deposition rate of calcium and magnesium impurities after processing reagents also increases to 20 m / h, and the content of impurities in the solution after clarification. reduced to 10 mg / l.

Example 1. The solution is fed with the reverse NaCl salt in an amount of 3250 kg / h, obtained directly after evaporation of the electromagnetic liquors and their separation. on a centrifuge. The chemical composition of the reverse salt,%: NaCl 99; N82804 5; NaOH 0.03. Granulometric composition of salt,% 0.4 mm 10.5; 0.2-0.315 mm 46; 0.16-0.20 m 6.5; OL-0.16 mm 25; 0.063-0.1 mm 8; 0.050, 063 mm 2.5; less than 0.05 mm J. As

the solvent uses production water, which is fed into the mixer in the amount of 3250 l / h. The remaining water in the amount of 5.5 is fed directly into the column solvent. The pre-mixed pulp of the indicated composition is fed from the mixing tank through a pass-through electromagnet with a speed of 0.9 m / s (magnetic field strength is 1800 Oe) and a neutralizer. Then 9 pulps enter the pulsation dissolution column, the cross section and height of which is chosen so that the maximum velocity of the solution (at the maximum amplitude of the pulsation) is 0.45 m / s, which corresponds to the pulsation intensity of 7000 mm / Min and the residence time of the solution in the column is 1 min. Approximately 3 solutions are returned through a pH meter to a mixer, where hydrochloric acid is fed for neutralization. The concentration of the solution at the exit from the pulsation column was 320 g / l (with an increase in the contact time of the dissolved salt with water in the pulsation dissolving column to 1.5 min, the concentration of the resulting brine is higher than 325 g / l)

In the sump, the clarification rate of the finished brine is 20 m / h. The total content of impurities (calcium and magnesium salts) in the finished brine is 10 mg / l.

PR, R m e R 2. Preparation of the reverse brine, the flow of water and pulp corresponds to example 1. The intensity of the pulsations in the column is 6500 mm / min. Before feeding into the column, the pulp is pretreated in a magnetic field of 1500 E with a velocity of 0.7 m / s. With the residence time of the treated suspension in the pulsation dissolving column, up to 1.5 minutes. The concentration of the brine obtained is 323 g / l. The rate of clarification of the finished brine in the settling tank is 18 m / h with a total impurity content of not more than 12 mg / l.

Example 3. The process corresponds to example 1, however, the magnetisation is subjected not only to the suspension, but also to that part of the water that is additionally supplied to the dissolution column under magnetisation modes: magnetic field strength 1750 Oe, water flow velocity in a magnetic field of 0.85 m / with. At the time of contact of the solution with the salt, 1.0 min, the concentration of the solution with the salt is 1.0 min, the concentration of the solution at the outlet of the column is 324 g / l, the rate of clarification of the finished solution in the sump is 20 m / g, and the total content of impurities in the final brine is 10 mg / l.

The implementation of the proposed method allows to reduce the time of dissolution of sodium chloride in water to 1.5-2 minutes, to increase the rate of precipitation of calcium and magnesium impurities up to 18-20 m / h, which is 2-2.5 times higher than the known value content of impurities in the solution after clarification to 10-15 g / l

(from 15-30 g / l as known), to obtain solutions with sodium chloride content up to 322-325 g / l at 20-25 ° C, which is above the saturation limit at this temperature.

Due to the Ili process, the dimensions of the equipment installed at the stage of dissolution and clarification of the solution are reduced.

Claims (3)

Claim 1. A method of preparing a solution of sodium chloride, including mixing sodium chloride with water, dissolving it, treating the resulting solution with reagents, precipitating and separating calcium and magnesium impurities from the solution, characterized in that, in order to increase the dissolution rate of sodium chloride, obtaining supersaturated in chloride sodium of the solution, increasing the rate of deposition of impurities and reducing the content of them in the solution, the pulp is subjected to treatment in a magnetic field before dissolution, and the dissolution is pulsed e. 2. The method of pop. 1, characterized in that the pulp is processed in a magnetic field with a strength of 1500-2000 Oe at a feed speed of 0.7-1.0 m / s, and dissolution in a pulsed mode is carried out at a pulsation intensity of 6000-8000 mm / min. 3. The method according to π. 1, due to the fact that before mixing with salt, they are treated in a magnetic field with a strength of 1500-2000 Oe and a feed speed of 0.7-1.0 m / s.