阅读说明：本技术 一种制备4n级氯化镁的方法 (Method for preparing 4N-grade magnesium chloride ) 是由 徐玉娜 钟学明 于 2019-11-07 设计创作，主要内容包括：本发明一种制备4N级氯化镁的方法以含镁的脱色制溴废液为料液、P507为萃取剂、TOPO为改性剂；由3个步骤段组成,分别为满载分馏萃取分离NaKMg/MgCaBaPbAlFe、满载分馏萃取分离NaK/Mg和分馏萃取分离Mg/CaBaPbAlFe；直接制备4N级氯化镁溶液。目标产品4N级氯化镁溶液的纯度为99.993％～99.998％,镁的收率为97％～99％。本发明具有产品纯度高、镁的收率高、试剂消耗少、分离效率高、工艺流程短、生产成本低等优点。(The invention relates to a method for preparing 4N-grade magnesium chloride, which takes magnesium-containing decolored bromine preparation waste liquid as feed liquid, P507 as an extracting agent and TOPO as a modifying agent; consists of 3 steps, namely full-load fractionation, extraction and separation of NaKMg/MgCaBaPbAlFe, full-load fractionation, extraction and separation of NaK/Mg and fractionation, extraction and separation of Mg/CaBaPbAlFe; directly preparing 4N-grade magnesium chloride solution. The purity of the 4N grade magnesium chloride solution of the target product is 99.993-99.998%, and the yield of magnesium is 97-99%. The method has the advantages of high product purity, high magnesium yield, low reagent consumption, high separation efficiency, short process flow, low production cost and the like.)

1. A method for preparing 4N-grade magnesium chloride is characterized by comprising the following steps: the method takes magnesium-containing decolorized bromine preparation waste liquid as a feed liquid, P507 as an extracting agent and TOPO as a modifier; separating and removing metal elements of sodium, potassium, calcium, barium, lead, aluminum and iron in the feed liquid, and separating and removing non-metal elements of sulfur, boron and silicon to directly prepare a 4N-grade magnesium chloride solution; consists of 3 steps, namely full-load fractionation, extraction and separation of NaKMg/MgCaBaPbAlFe, full-load fractionation, extraction and separation of NaK/Mg and fractionation, extraction and separation of Mg/CaBaPbAlFe; the extraction section of full-load fractionation, extraction and separation NaKMg/MgCaBaPbAlFe realizes the separation of NaKMg/CaBaPbAlFe, and the washing section realizes the separation of NaK/MgCaBaPbAlFe; full-load fractionation, extraction and separation of NaKMg/MgCaBaPbAlFe, namely, a balanced load P507 organic phase obtained by full-load fractionation, extraction and separation of NaK/Mg feeding level is taken as an extraction organic phase, and a balanced water phase obtained by fractionation, extraction and separation of Mg/CaBaPbAlFe feeding level is taken as a detergent; full-load fractionation, extraction and separation of NaK/Mg and fractionation, extraction and separation of Mg/CaBaPbAlFe are directly connected in series; the outlet organic phase which is fully loaded with NaK/Mg and is separated by fractional extraction is used as an extraction organic phase for separating Mg/CaBaPbAlFe by fractional extraction, and directly enters the 1 st stage of separating Mg/CaBaPbAlFe by fractional extraction; the 1 st level outlet water phase of the Mg/CaBaPbAlFe separation by fractional extraction is used as a detergent for separating NaK/Mg by full-load fractional extraction;

the 3 steps are as follows:

step 1: full-load fractional extraction separation of NaKMg/MgCaBaPbAlFe

Taking a balanced load P507 organic phase obtained by the feed stage of the NaK/Mg full-load fractional extraction system in the step 2 as an extraction organic phase, taking decolorized bromine-making waste liquid containing magnesium as a feed liquid, and taking a balanced water phase obtained by the feed stage of the Mg/CaBaPbAlFe fractional extraction system in the step 3 as a detergent; the equilibrium loaded P507 organic phase obtained from the feed stage of the NaK/Mg full-load fractionation extraction system in the step 2 enters a NaKMg/MgCaBaPbAlFe full-load fractionation extraction system from the 1 st stage, the magnesium-containing decolorized bromine-making waste liquid enters the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system from the feed stage, and the equilibrium aqueous phase obtained from the feed stage of the Mg/CaBaPbAlFe fractionation extraction system in the step 3 enters the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system from the last 1 st stage; obtaining a magnesium chloride solution containing Na, K, S, B and Si from the water phase at the 1 st level outlet of the NaKMg/MgCaBaPbAlFe full-load fractional extraction system, and using the magnesium chloride solution as feed liquid for full-load fractional extraction separation of NaK/Mg in the step 2; obtaining a P507 organic phase loaded with Mg-Ca-Ba-Pb-Al-Fe from the last 1-level outlet organic phase of the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system, and using the P507 organic phase as feed liquid for fractionating, extracting and separating Mg/CaBaPbAlFe in the step 3;

step 2: full-load fractional extraction for separating NaK/Mg

Taking a saponified P507 organic phase as an extraction organic phase, taking a magnesium chloride solution containing Na, K, S, B and Si obtained from a No. 1 outlet aqueous phase of a NaKMg/MgCaBaPbAlFe full-load fractionation extraction system in the step 1 as a feed liquid, and taking a 4N grade magnesium chloride solution obtained from a No. 1 outlet aqueous phase of a Mg/CaBaPbAlFe fractionation extraction system in the step 3 as a washing agent; the saponification P507 organic phase enters a NaK/Mg full-load fractionation extraction system from the 1 st level as an extraction organic phase, a magnesium chloride solution containing Na, K, S, B and Si and obtained from a water phase at the 1 st level outlet of the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system in the step 1 enters the NaK/Mg full-load fractionation extraction system from a feeding level, and a 4N-level magnesium chloride solution obtained from a water phase at the 1 st level outlet of the Mg/CaBaPbAlFe fractionation extraction system in the step 3 enters the NaK/Mg full-load fractionation extraction system from the last 1 level; obtaining sodium chloride and potassium chloride mixed solution containing S, B and Si from the water phase at the 1 st stage outlet of a NaK/Mg full-load fractional extraction system; separating a balanced load P507 organic phase of a feed grade of a NaK/Mg full-load fractional extraction system, and using the balanced load P507 organic phase as an extraction organic phase for full-load fractional extraction separation of NaKMg/MgCaBaPbAlFe in the step 1; obtaining a P507 organic phase loaded with magnesium from the last 1-level outlet organic phase of the NaK/Mg full-load fractionation extraction system, and using the P507 organic phase as an extraction organic phase for fractionating, extracting and separating Mg/CaBaPbAlFe in the step 3;

and step 3: fractionation, extraction and separation of Mg/CaBaPbAlFe

Taking a P507 organic phase loaded with magnesium obtained from the last level 1 of the NaK/Mg full-load fractionation extraction system in the step 2 as an extraction organic phase, taking a P507 organic phase loaded with magnesium, calcium, barium, lead, aluminum and iron obtained from the last level 1 of the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system in the step 1 as a feed liquid, and taking 8.0mol/L HCl as a washing acid; the P507 organic phase loaded with magnesium and obtained from the last 1 level of the NaK/Mg full-load fractionation extraction system in the step 2 enters into a Mg/CaBaPbAlFe fractionation extraction system from the 1 st level, the P507 organic phase loaded with magnesium, calcium, barium, lead, aluminum and iron and obtained from the last 1 level of the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system in the step 1 enters into the Mg/CaBaPbAlFe fractionation extraction system from a feeding level, and 8.0mol/L HCl washing acid enters into the Mg/CaBaPbAlFe fractionation extraction system from the last 1 level; obtaining a target product of 4N-grade magnesium chloride solution from a 1 st-grade outlet water phase of the Mg/CaBaPbAlFe fractional extraction system, and taking the 4N-grade magnesium chloride solution as a detergent of the NaK/Mg full-load fractional extraction system in the step 2; separating a feed-grade equilibrium water phase of the Mg/CaBaPbAlFe fractional extraction system, and using the balance water phase as a detergent for separating NaKMg/MgCaBaPbAlFe through full-load fractional extraction in the step 1; and obtaining a P507 organic phase loaded with calcium barium lead aluminum iron from the last 1-stage outlet organic phase of the Mg/CaBaPbAlFe fractional extraction system.

2. The process for preparing 4N grade magnesium chloride according to claim 1, characterized in that: the P507 organic phase is a kerosene solution of P507 and TOPO, wherein the concentration of the P507 is 1.0mol/L, and the concentration of the TOPO is 0.05 mol/L; when used, the P507 organic phase is saponified by ammonia saponification and sodium saponification to obtain a saponified P507 organic phase.

3. The process for preparing 4N grade magnesium chloride according to claim 1, characterized in that: the concentration of relevant elements of the magnesium-containing decolorized bromine preparation waste liquid is respectively as follows: s3.0-7.0 g/L, B0.010.010-0.030 g/L, Si 0.010.010-0.030 g/L, Na 3.0.0-5.0 g/L, K0.010.010-0.030 g/L, Mg 70.0.0-100.0 g/L, Ca0.050g/L-0.150 g/L, Ba 0.010.010-0.030 g/L, Pb 0.010.010-0.030 g/L, Al 0.10.10-0.30 g/L, Fe 0.10.10-0.30 g/L.

4. The process for preparing 4N grade magnesium chloride according to claim 1, characterized in that: the concentration of related elements in the 4N-grade magnesium chloride solution is respectively as follows: s0.00010 g/L-0.00050 g/L, B0.00010.00010 g/L-0.00030 g/L, Si 0.00010.00010 g/L-0.00030 g/L, Na 0.00020.00020 g/L-0.00080 g/L, K0.00010.00010 g/L-0.00070 g/L, Mg 92.0.0 g/L-96.0 g/L, Ca 0.0010.0010 g/L-0.0050 g/L, Ba0.0005.0 g/L-0.0020 g/L, Pb0.00010g/L-0.00030 g/L, Al 0.00010.00010 g/L-0.00030 g/L, Fe 0.00010.00010 g/L-0.00030 g/L.

Technical Field

The invention relates to a method for preparing 4N-grade magnesium chloride, in particular to a method for directly preparing 4N-grade magnesium chloride solution by taking decolorized bromine preparation waste liquid containing magnesium as a feed liquid, P507 as an extracting agent and TOPO as a modifying agent, separating and removing metal elements such as sodium, potassium, calcium, barium, lead, aluminum, iron and the like in the feed liquid and non-metal elements such as sulfur, boron, silicon and the like. The invention belongs to the technical field of preparation of 4N-grade magnesium chloride.

Background

The industrial bromine preparation process must produce a waste liquid with complex composition and high magnesium content, and the waste liquid becomes an important resource for extracting magnesium. The general process flow for extracting magnesium chloride from bromine production waste liquid is as follows: decolorizing by an oxidation method, removing sulfur by a barium chloride precipitation method, removing boron by an ion exchange method, removing barium and calcium by a sodium carbonate precipitation method, removing heavy metals by a sodium sulfide precipitation method, concentrating and crystallizing, and finally obtaining a 2N-grade magnesium chloride product. It is easy to find that the existing method for extracting magnesium chloride from bromine production waste liquid has the defects of long process flow, complicated operation (precipitation, filtration and washing), low product purity (2N grade), high production cost and the like.

The invention provides a method with short process flow, high purity of magnesium chloride products and low production cost aiming at the defects of long process flow, complex operation, low product purity, high production cost and the like of the existing method for extracting magnesium chloride from bromine preparation waste liquid, and 4N-grade magnesium chloride solution is directly prepared by taking magnesium-containing decolored bromine preparation waste liquid as feed liquid.

Disclosure of Invention

The invention provides a method for preparing 4N-grade magnesium chloride, which aims at the defects of long process flow, complex operation, low product purity, high production cost and the like of the existing method for extracting magnesium chloride from bromine preparation waste liquid and provides a method for directly preparing 4N-grade magnesium chloride solution from magnesium-containing decolored bromine preparation waste liquid.

The invention relates to a method for preparing 4N-grade magnesium chloride, which takes decolorized bromine preparation waste liquid containing magnesium as a feed liquid, 2-ethylhexyl phosphonic acid mono 2-ethylhexyl hexyl phosphonic acid (P507) as an extracting agent and trioctyl phosphorus oxide (TOPO) as a modifier, separates and removes metal elements such as sodium, potassium, calcium, barium, lead, aluminum, iron and the like in the feed liquid, and separates and removes non-metal elements such as sulfur, boron, silicon and the like, thereby directly preparing the 4N-grade magnesium chloride solution.

The invention relates to a method for preparing 4N-grade magnesium chloride, which consists of 3 steps, namely full-load fractional extraction separation NaKMg/MgCaBaPbAlFe, full-load fractional extraction separation NaK/Mg and fractional extraction separation Mg/CaBaPbAlFe; the extraction section of full-load fractionation, extraction and separation NaKMg/MgCaBaPbAlFe realizes the separation of NaKMg/CaBaPbAlFe, and the washing section realizes the separation of NaK/MgCaBaPbAlFe; the method is characterized in that NaKMg/MgCaBaPbAlFe is separated by full-load fractionation and extraction, a balanced load P507 organic phase obtained by separating NaK/Mg feeding grade by full-load fractionation and extraction is used as an extraction organic phase, and a balanced aqueous phase obtained by separating Mg/CaBaPbAlFe feeding grade by fractionation and extraction is used as a detergent. Full-load fractionation, extraction and separation of NaK/Mg and fractionation, extraction and separation of Mg/CaBaPbAlFe are directly connected in series; the outlet organic phase which is fully loaded with NaK/Mg and is separated by fractional extraction is used as an extraction organic phase for separating Mg/CaBaPbAlFe by fractional extraction, and directly enters the 1 st stage of separating Mg/CaBaPbAlFe by fractional extraction; the 1 st stage outlet aqueous phase of the Mg/CaBaPbAlFe separation by fractional extraction is used as a washing agent for full-load fractional extraction and separation of NaK/Mg.

The method for preparing the 4N-grade magnesium chloride comprises the following 3 steps:

step 1: full-load fractional extraction separation of NaKMg/MgCaBaPbAlFe

Step 1 is full-load fractionation, extraction and separation of NaKMg/MgCaBaPbAlFe, the extraction section realizes the separation of NaKMg/CaBaPbAlFe, and the washing section realizes the separation of NaK/MgCaBaPbAlFe. And (3) taking a balanced load P507 organic phase obtained by the feed stage of the NaK/Mg full-load fractional extraction system in the step 2 as an extraction organic phase, taking decolorized bromine-making waste liquid containing magnesium as a feed liquid, and taking a balanced water phase obtained by the feed stage of the Mg/CaBaPbAlFe fractional extraction system in the step 3 as a detergent. And (3) feeding the balance water phase obtained from the feeding stage of the Mg/CaBaPbAlFe fractional extraction system in the step 3 into the NaKMg/MgCaBaPbAlFe full-load fractional extraction system from the last 1 stage. Obtaining a magnesium chloride solution containing Na, K, S, B and Si from the water phase at the 1 st level outlet of the NaKMg/MgCaBaPbAlFe full-load fractional extraction system, and using the magnesium chloride solution as feed liquid for full-load fractional extraction separation of NaK/Mg in the step 2; and (3) obtaining a P507 organic phase loaded with Mg-Ca-Ba-Pb-Al-Fe from the last 1-stage outlet organic phase of the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system, and using the P507 organic phase as the feed liquid for fractionating, extracting and separating Mg/CaBaPbAlFe in the step 3.

Step 2: full-load fractional extraction for separating NaK/Mg

And step 2, full-load fractionation, extraction and separation of NaK/Mg, and separation and removal of metallic element impurities of sodium and potassium and non-metallic element impurities of sulfur, boron and silicon in the magnesium chloride solution. Taking a saponified P507 organic phase as an extraction organic phase, taking a magnesium chloride solution containing Na, K, S, B and Si obtained from a No. 1 outlet aqueous phase of a NaKMg/MgCaBaPbAlFe full-load fractionation extraction system in the step 1 as a feed liquid, and taking a 4N grade magnesium chloride solution obtained from a No. 1 outlet aqueous phase of a Mg/CaBaPbAlFe fractionation extraction system in the step 3 as a washing agent. The saponified P507 organic phase is an extraction organic phase and enters a NaK/Mg full-load fractionation extraction system from the 1 st level, a magnesium chloride solution containing Na, K, S, B and Si and obtained from a water phase at the 1 st level outlet of the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system in the step 1 enters a NaK/Mg full-load fractionation extraction system from a feeding level, and a 4N level magnesium chloride solution obtained from a water phase at the 1 st level outlet of the Mg/CaBaPbAlFe fractionation extraction system in the step 3 enters a Mg/CaBaPbAlFe fractionation extraction system from the last 1 level. Obtaining sodium chloride and potassium chloride mixed solution containing S, B and Si from the water phase at the 1 st stage outlet of a NaK/Mg full-load fractional extraction system; separating a balanced load P507 organic phase of a feed grade of a NaK/Mg full-load fractional extraction system, and using the balanced load P507 organic phase as an extraction organic phase for full-load fractional extraction separation of NaKMg/MgCaBaPbAlFe in the step 1; and (3) obtaining a magnesium-loaded P507 organic phase from the last grade 1 outlet organic phase of the NaK/Mg full-load fractional extraction system, and using the magnesium-loaded P507 organic phase as an extraction organic phase for fractional extraction and separation of Mg/CaBaPbAlFe in the step 3.

And step 3: fractionation, extraction and separation of Mg/CaBaPbAlFe

And 3, fractionating, extracting and separating Mg/CaBaPbAlFe to realize the separation of magnesium from calcium, barium, lead, aluminum and iron. Taking a P507 organic phase loaded with magnesium obtained from the last level 1 of the NaK/Mg full-load fractionation extraction system in the step 2 as an extraction organic phase, taking a P507 organic phase loaded with magnesium, calcium, barium, lead, aluminum and iron obtained from the last level 1 of the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system in the step 1 as a feed liquid, and taking 8.0mol/L HCl as a washing acid. The P507 organic phase loaded with magnesium obtained from the last level 1 of the NaK/Mg full-load fractionation extraction system in the step 2 enters into a Mg/CaBaPbAlFe fractionation extraction system from the level 1, the P507 organic phase loaded with magnesium, calcium, barium, lead, aluminum and iron obtained from the last level 1 of the NaKMg/MgCaBaPbAlFe full-load fractionation extraction system in the step 1 enters into the Mg/CaBaPbAlFe fractionation extraction system from a feeding level, and 8.0mol/L HCl washing acid enters into the Mg/CaBaPbAlFe fractionation extraction system from the last level 1. Obtaining a target product of 4N-grade magnesium chloride solution from a 1 st-grade outlet water phase of the Mg/CaBaPbAlFe fractional extraction system, and taking the 4N-grade magnesium chloride solution as a detergent of the NaK/Mg full-load fractional extraction system in the step 2; separating a feed-grade equilibrium water phase of the Mg/CaBaPbAlFe fractional extraction system, and using the balance water phase as a detergent for separating NaKMg/MgCaBaPbAlFe through full-load fractional extraction in the step 1; and obtaining a P507 organic phase loaded with calcium, barium, lead, aluminum and iron from the final level 1 outlet organic phase of the Mg/CaBaPbAlFe fractional extraction system, and recovering valuable elements after back extraction.

The P507 organic phase is a kerosene solution of P507 and TOPO, wherein the concentration of the P507 is 1.0mol/L, and the concentration of the TOPO is 0.05 mol/L. When used, the P507 organic phase is saponified by ammonia saponification and sodium saponification to obtain a saponified P507 organic phase.

The concentration of relevant elements of the magnesium-containing decolorized bromine preparation waste liquid is respectively as follows: 3.0-7.0 g/L S, 0.010g/L-0.030 g/L, Si 0.010.010-0.030 g/L, Na 3.0.0-5.0 g/L, K0.010-0.030 g/L, Mg 70.0.0-100.0 g/L, Ca 0.050.050 g/L-0.150 g/L, Ba 0.010.010-0.030 g/L Pb0.010g/L-0.030 g/L, Al 0.10.10 g/L-0.30 g/L, Fe 0.10 g/L-0.30 g/L.

The concentration of related elements in the 4N-grade magnesium chloride solution is respectively as follows: s0.00010 g/L-0.00050 g/L, B0.00010g/L-0.00030 g/L, Si 0.00010.00010 g/L-0.00030 g/L, Na 0.00020.00020 g/L-0.00080 g/L, K0.00010g/L-0.00070 g/L, Mg 92.0.0 g/L-96.0 g/L, Ca 0.0010.0010 g/L-0.0050 g/L, Ba0.0005.0g/L-0.0020 g/L, Pb 0.00010.00010 g/L-0.00030 g/L/L, Al 0.00010.00010 g/L-0.00030 g/L and Fe0.00010g/L-0.00030 g/L.

The invention has the beneficial effects that: 1) directly obtaining a 4N-grade magnesium chloride solution from decolorized bromine preparation waste liquid containing magnesium. After the 4N-grade magnesium chloride solution is subjected to post-treatment such as concentration crystallization or precipitation, a series of 4N-grade magnesium-containing compounds such as 4N-grade magnesium chloride crystals and 4N-grade magnesium phosphate crystals can be obtained. 2) The product purity is high, and the yield of magnesium is high: the purity of the 4N grade magnesium chloride solution of the target product is 99.993-99.998%, and the yield of magnesium is 97-99%. 3) Zero reagent consumption is less: the outlet organic phase which is fully loaded with NaK/Mg and separated by fractional extraction is used as an extraction organic phase for separating Mg/CaBaPbAlFe by fractional extraction, and directly enters the 1 st stage of separating Mg/CaBaPbAlFe by fractional extraction, so that saponification alkali for separating Mg/CaBaPbAlFe by fractional extraction is saved. The water phase at the 1 st stage outlet for fractionating, extracting and separating Mg/CaBaPbAlFe is used as a detergent for separating NaK/Mg by full-load fractionating, extracting and separating, and the washing acid for separating NaK/Mg by full-load fractionating, extracting and separating is saved. 4) The separation efficiency is high: and 3 separation sections (full-load fractionation extraction separation NaKMg/MgCaBaPbAlFe, full-load fractionation extraction separation NaK/Mg, fractionation extraction separation Mg/CaBaPbAlFe) separate and remove metal impurities such as sodium, potassium, calcium, barium, lead, aluminum, iron and the like and non-metal impurities such as sulfur, boron, silicon and the like in the magnesium-containing decoloration bromine preparation waste liquid. 5) The process flow is short: the method for directly preparing 4N-grade magnesium chloride from magnesium-containing decolored bromine preparation waste liquid consists of 3 separation sections. The method is characterized in that NaKMg/MgCaBaPbAlFe is separated by full-load fractionation and extraction, and a balanced load P507 organic phase obtained by full-load fractionation, extraction and separation of NaK/Mg feeding level is used as an extraction organic phase, so that a saponification section is not needed for full-load fractionation, extraction and separation of NaKMg/MgCaBaPbAlFe; the equilibrium water phase obtained by fractionating, extracting and separating the Mg/CaBaPbAlFe feeding level is a detergent, so that a stripping section is not needed for full-load fractionating, extracting and separating NaKMg/MgCaBaPbAlFe. The full-load fractional extraction separation NaKMg/MgCaBaPbAlFe and the full-load fractional extraction separation NaK/Mg share a saponification section. The outlet organic phase which is fully loaded with NaK/Mg and is separated by fractional extraction is used as the extraction organic phase for separating Mg/CaBaPbAlFe by fractional extraction, so that the saponification section is not needed for separating Mg/CaBaPbAlFe by fractional extraction. The outlet organic phase of the full-load fractional extraction for separating the NaK/Mg is used as an extraction organic phase of the fractional extraction for separating the Mg/CaBaPbAlFe, so the fractional extraction for separating the full-load fractional extraction for separating the NaK/Mg does not need a washing section. 6) The production cost is low: high separation efficiency, short process flow and less reagent consumption.

Drawings

FIG. 1: the invention discloses a process flow schematic diagram of a method for preparing 4N-grade magnesium chloride. In FIG. 1, LOP denotes the loaded organic phase; w represents a detergent; 4N Mg represents a 4N grade magnesium chloride solution.

Detailed Description

A process for preparing 4N grade magnesium chloride according to the present invention will be further described with reference to the following specific examples.