SU1393790A1 - Method of purifying brine from magnesium and calcium ions - Google Patents

Abstract

The present invention relates to the purification of sodium chloride solutions from magnesium and calcium ions for the use of purified brines in the production of soda and reduces the loss of brine during the purification process. According to the method, the initial brine is precontacted with a thickened gypsum magnetization suspension at a volume ratio of 5-10: 1. After the sludge has been separated, the brine is treated with a lime suspension, the resulting hypomagnesia suspension is thickened, separated from the brine and sent to the initial brine pretreatment step. The clarified brine is then treated with soda, followed by separation of the calcium carbonate precipitate to obtain a purified brine. 1 tabl.Q

Description

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The invention relates to the purification of solutions of sodium chloride from impurities, and in particular from magnesium and calcium ions, for the use of solid solutions in the production of soda.

The aim of the invention is to reduce the loss of the purified brine.

PRI me R 1 (by a known method;.

1200 kg of the initial brine content, kg: NaCl 299.92; MgCl3,31; MgS04 8.19; CaSO2,82; water 885.76 to be purified from magnesium salts, (; stirrer in the first stage reactor; 79.34 kg of lime slurry with Content, kg: NaCl 18.0; Ca (OH) 2

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 1279.34 kg of suspension from the reactor enters the settling tank, from which; A dump of 162.18 kg of condensed g of ipso-magnesia suspension containing 17.27 kg of solids and M4.91 kg of brine, and 1124.4 kg of ras, to be purified from Ca, with Content, kg: NaCl 281.2; CaS04 CaCl 3.64; SASON) 0.47, mixture | They are supplied in another reactor with 150 kg with | a monolithic solution containing, ijr: NaCl 33.55; , 8.53; water . 108., O. Suspension from the reactor enters the sedimentation tank of the second purification stage, where kg of condensed suspension containing 7.5 kg of CaCO and 33.34 kg of vassol, with content, kg: NaCl

309.2; water 913.0; Other impurities are 6.8; they are divided into two streams, one of which with a content of 33.5 kg of NaCl is directed to preparation with a single-salt solution, and the other with a content of 275.76 kg of NaCl is fed into the production of soda.

The loss of brine was 13.5 wt.%; lime consumption (85% QaO) -8.54 kg / m o; soda consumption (100% NajCO,) - 9.56 kg / m.

PRI mme R 2. 600 kg of the original brine content, kg: NaCl 150; MgCli 1.65; 4.05; CaSO1,38; Water 443 is mixed in a reactor with 125.7 kg of a condensed gypsum-magnesia suspension containing 14.35 kg of solid substances and 111.35 kg of brine. The volume ratio of the thickened suspension | and: the initial brine is 1: 5.0. The suspension enters a settling tank, from which 127.13 kg of a thickened hypomagnesia suspension containing 14.35 kg of solids and 112.78 kg

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brine (NaCl 29; MgCl20.27; MgS04 0.66) is fed to the discharge, and 598.68 kg of brine containing, kg: NaCl 149.7j MgCl.j, l, 38; MgS04 3.44; CaSO1,56; CaCl 0.31; water 885.3 to be purified from magnesium salts is mixed in a reactor with 600 kg of initial brine and 72.06 kg of lime suspension containing, kg: NaCl 16.53; Ca (OH) 2 7.45; water 47.0; other impurities 1.23. The suspension enters a settling tank, where 128.7 kg of a thickened hypomagnesia suspension is formed, of which 3.0 kg is thrown into the dump, 125.7 kg containing 14.35 kg of solids and 111.35 kg of brine are mixed with the original brine, and 1148.7 kg of brine to be purified from Ca, with a content of 8.64 kg of calcium salts and 287.7 kg of NaCl is fed into the reactor of the second stage of purification for mixing with 145.8 kg of saline solution containing, kg: NaCl 32.6; Na, jCO, 8.31 j of water 104.9. Next, the suspension enters the settling tank, from which 39.4 kg of the condensed calcium carbonate-containing suspension enters the dump, and 1252.4 kg of the purified brine enters the collection of the purified brine, from where part of the brine enters the preparation of saline solution, and 1106, 6 kg of purified brine containing, kg: NaCl 283.5; water 825.2; other impurities 5.73, enters the production of soda ash.

The loss of brine is 11.72 wt.%.: Lime consumption (85% CaO) - 7.66 kg / m o; soda consumption (100%) - 9.08 kg / / m o.r.

PRI me R 3. 1200 kg of the original brine containing, kg: NaCl 299,92; MgCl3,31; MgSO 8.10; CaSO ,, 2.82; water 885.76, is mixed in the reactor with 125.7 kg of a condensed hypomagnesia suspension containing 14.35 kg of solids and 111.35 kg of brine, purified from magnesium salts. The volume ratio of the thickened suspension: brine is 1: 10.0; 1325.7 kg of the suspension enters the ottogen, from which 125.78 kg of the condensed gypsum-magnesia suspension containing 14.35 kg of solids and 111.38 kg of brine (28.75 NaCl; MgCl 0.29; MgSO 0.71) is fed to the discharge and 1199.86 kg

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containing, kg: NaCl 299,84

brine,

MgCL 3.02; MgSO 7.48; other impurities 3.42; water 886.13, subject to purification from magnesium salts, is mixed in the reactor with 72.03 kg of lime suspension containing, kg: NaCl 16.53; Ca (OH) 7.42. The suspension enters a settling tank, where 128.2 kg of condensed hypomagnesia suspension is formed, of which 2.5 kg is sent to the dump, and 125.7 kg containing 14.35 kg of solids and 111.15 kg of brine are mixed with the original brine, and 1148.7 kg of brine, purified from magnesium content, kg: NaCl 287.7; CaSO4,52; CaClj 3.67; Ca (LH), 0.45; water 848.1, sent to remove salts from salt. Mix up with 145.8 kg of brine containing: NaCl 32.6; 8.31; water 104.9, in the second stage purification reactor. The suspension enters the settling tank, from where 39.4 kg of the condensed suspension containing the precipitate CaCOj is sent to the dump, and 1252.4 kg of the purified

They are divided into two streams: one of them, with a content of 32.6 kg of NaCl, is directed to the preparation of a soda-saline solution, and the other with a content of 283.5 kg of NaCl is sent to the production of soda.

The loss of brine is 11.64% by weight; lime consumption (85% CaO) - 7.61 kg / m o.R .; soda consumption (100%,) - 9.07 kg / - -. р.

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 The results of the experiments are shown in the table.

The proposed method allows to reduce the loss of brine by 1.8-2.4% compared with the known, as well as reduce the cost of cleaning reagents by 10-11% for lime and 4.8-5.0% for soda.

Claims (1)

Invention Formula A method for purifying brine from magnesium and calcium ions, including brine processing with lime suspension, thickening gypsum-magnesia suspension formed, separating the suspension from brine, treating the latter with soda, and separating the resulting calcium carbonate precipitate, characterized in that, in order to reduce the loss of saline , the initial brine is precontacted with a condensed hypomomagnesia suspension at their volume ratio of 5-10: 1s, followed by settling and separation of the brine from the condensed suspension ..