阅读说明：本技术 一种制备6n级硫酸镁溶液的方法 (Method for preparing 6N-grade magnesium sulfate solution ) 是由 李艳容 钟学明 于 2019-11-20 设计创作，主要内容包括：本发明一种制备6N级硫酸镁溶液的方法,以4N级硫酸镁溶液为料液、C272为萃取剂,由满载分馏萃取分离NaKMg/MgCaPbAlFe、满载分馏萃取分离NaK/Mg和分馏萃取分离Mg/CaPbAlFe三3个步骤段组成；分离除去料液中的钠、钾、钙、铅、铝、铁等金属元素,以及分离除去氯、硅、砷等非金属元素,制备6N级硫酸镁溶液。目标产品6N级硫酸镁溶液的纯度为99.99992%～99.99998%,4N级硫酸镁溶液中镁的收率为95%～97%。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 6N-grade magnesium sulfate solution, which takes 4N-grade magnesium sulfate solution as feed liquid and C272 as an extracting agent and consists of three 3 steps of full-load fractional extraction separation of NaKMg/MgCaPbAlFe, full-load fractional extraction separation of NaK/Mg and fractional extraction separation of Mg/CaPbAlFe; separating and removing metal elements such as sodium, potassium, calcium, lead, aluminum, iron and the like in the feed liquid, and separating and removing nonmetal elements such as chlorine, silicon, arsenic and the like to prepare a 6N-grade magnesium sulfate solution. The purity of the 6N-grade magnesium sulfate solution of the target product is 99.99992-99.99998%, and the yield of magnesium in the 4N-grade magnesium sulfate solution is 95-97%. 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 6N-grade magnesium sulfate solution is characterized by comprising the following steps: the method takes 4N-grade magnesium sulfate solution as feed liquid and C272 as an extracting agent, and separates and removes metallic element impurities of sodium, potassium, calcium, lead, aluminum and iron in the feed liquid, and non-metallic elements of chlorine, silicon and arsenic to prepare 6N-grade magnesium sulfate solution; consists of 3 steps, namely full-load fractionation, extraction and separation of NaKMg/MgCaPbAlFe, full-load fractionation, extraction and separation of NaK/Mg and fractionation, extraction and separation of Mg/CaPbAlFe; the extraction section of full-load fractionation, extraction and separation NaKMg/MgCaPbAlFe realizes the separation of NaKMg/CaPbAlFe, and the washing section realizes the separation of NaK/MgCaPbAlFe; full-load fractionation, extraction and separation of NaKMg/MgCaPbAlFe, full-load fractionation, extraction and separation of NaK/Mg, a balanced load C272 organic phase obtained at a feed level is used as an extraction organic phase, and a balanced water phase obtained at a feed level is used as a detergent; full-load fractionation, extraction and separation of NaK/Mg and fractionation, extraction and separation of Mg/CaPbAlFe are directly connected in series; 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/CaPbAlFe by fractional extraction, and directly enters the 1 st stage for separating Mg/CaPbAlFe by fractional extraction; the 1 st level outlet water phase of the Mg/CaPbAlFe 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/MgCaPbAlFe

Step 1, full-load fractionation, extraction and separation of NaKMg/MgCaPbAlFe, wherein the extraction section realizes the separation of NaKMg/CaPbAlFe, and the washing section realizes the separation of NaK/MgCaPbAlFe; using a balanced loaded C272 organic phase obtained from the feed stage of the NaK/Mg full-load fractionation extraction system in the step 2 as an extraction organic phase, using 4N-grade magnesium sulfate as a feed liquid, and using a balanced water phase obtained from the feed stage of the Mg/CaPbAlFe fractionation extraction system in the step 3 as a detergent; the equilibrium loaded C272 organic phase obtained from the feed stage of the NaK/Mg full-load fractionation extraction system in the step 2 enters a NaKMg/MgCaPbAlFe full-load fractionation extraction system from the 1 st stage, 4N-stage magnesium sulfate enters the NaKMg/MgCaPbAlFe full-load fractionation extraction system from the feed stage, and the equilibrium aqueous phase obtained from the feed stage of the Mg/CaPbAlFe fractionation extraction system in the step 3 enters the NaKMg/MgCaPbAlFe full-load fractionation extraction system from the last stage 1; obtaining a magnesium sulfate solution containing Na, K, Cl, Si and As from the water phase at the 1 st level outlet of the NaKMg/MgCaPbAlFe full-load fractional extraction system, and using the magnesium sulfate solution As a feed liquid for full-load fractional extraction and separation of NaK/Mg in the step 2; obtaining a C272 organic phase loaded with Mg-Ca-Pb-Al-Fe from the last 1-level outlet organic phase of the NaKMg/MgCaPbAlFe full-load fractional extraction system, and using the C272 organic phase as feed liquid for fractional extraction and separation of Mg/CaPbAlFe in the step 3;

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

Step 2, full-load fractionation, extraction and separation of NaK/Mg are carried out, and metal element impurities of sodium and potassium and non-metal element impurities of chlorine, silicon and arsenic in the magnesium sulfate solution are removed through separation; taking an ammonia saponification C272 organic phase As an extraction organic phase, taking a magnesium sulfate solution containing Na, K, Cl, Si and As obtained by fully fractionating a 1 st-grade outlet water phase of an extraction system with NaKMg/MgCaPbAlFe in the step 1 As a feed liquid, and taking a 6N-grade magnesium sulfate solution obtained by fractionating the 1 st-grade outlet water phase of the extraction system with Mg/CaPbAlFe in the step 3 As a detergent; the ammoniated saponified C272 organic phase enters a NaK/Mg full-load fractionation extraction system from the 1 st level, a magnesium sulfate solution containing Na, K, Cl, Si and As, which is obtained from the 1 st level outlet aqueous phase of the NaKMg/MgCaPbAlFe full-load fractionation extraction system of the step 1, enters the NaK/Mg full-load fractionation extraction system from a feeding level, and a 6N level magnesium sulfate solution obtained from the 1 st level outlet aqueous phase of the Mg/CaPbAlFe fractionation extraction system of the step 3 enters the NaK/Mg full-load fractionation extraction system from the last 1 level; obtaining a mixture solution containing sodium, potassium, chlorine, silicon and arsenic from the water phase at the 1 st stage outlet of a NaK/Mg full-load fractional extraction system; separating a balanced load C272 organic phase of a feed grade of a NaK/Mg full-load fractional extraction system, and using the balanced load C272 organic phase as an extraction organic phase for full-load fractional extraction separation of NaKMg/MgCaPbAlFe in the step 1; obtaining a C272 organic phase loaded with magnesium from the last level 1 outlet organic phase of the NaK/Mg full-load fractionation extraction system, and using the C272 organic phase as an extraction organic phase for fractionating, extracting and separating Mg/CaPbAlFe in the step 3;

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

Step 3, fractionating, extracting and separating Mg/CaPbAlFe to realize the separation of magnesium from calcium, lead, aluminum and iron; taking a C272 organic phase loaded with magnesium and 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 C272 organic phase loaded with magnesium, calcium, lead, aluminum and iron and obtained from the last level 1 of the NaKMg/MgCaPbAlFe full-load fractionation extraction system in the step 1 as a feed liquid, and taking 2.5mol/L sulfuric acid as a washing acid; the C272 organic phase loaded with magnesium and obtained from the last level 1 of the NaK/Mg full-load fractionation extraction system in the step 2 enters the Mg/CaPbAlFe fractionation extraction system from the level 1, the C272 organic phase loaded with magnesium, calcium, lead, aluminum and iron and obtained from the last level 1 of the NaKMg/MgCaPbAlFe full-load fractionation extraction system in the step 1 enters the Mg/CaPbAlFe fractionation extraction system from the feeding level, and 2.5mol/L sulfuric acid washing acid enters the Mg/CaPbAlFe fractionation extraction system from the last level 1; obtaining a target product 6N-grade magnesium sulfate solution from a 1 st grade outlet water phase of the Mg/CaPbAlFe fractional extraction system, and taking the 6N-grade magnesium sulfate 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/CaPbAlFe fractional extraction system to be used as a detergent for separating NaKMg/MgCaPbAlFe by full-load fractional extraction in the step 1; and obtaining a C272 organic phase loaded with calcium, lead, aluminum and iron from the final stage 1 outlet organic phase of the Mg/CaPbAlFe fractional extraction system.

2. The method of claim 1, wherein the method comprises the following steps: the C272 organic phase is a sulfonated kerosene solution of C272, wherein the concentration of the C272 is 1.0 mol/L; when used, the C272 organic phase is saponified with aqueous ammonia to obtain an ammonolyzed C272 organic phase.

3. The method of claim 1, wherein the method comprises the following steps: the element concentrations in the 4N-grade magnesium sulfate solution are respectively as follows: cl 0.00010 g/L-0.00050 g/L, Si 0.00010.00010 g/L-0.00030 g/L, As 0.00010.00010 g/L-0.00030 g/L, Na 0.00010.00010 g/L-0.00070 g/L, K0.00010.00010 g/L-0.00050 g/L, Mg 58.0.0 g/L-62.0 g/L, Ca 0.0010.0010 g/L-0.0050 g/L, Pb 0.00010.00010 g/L-0.00030 g/L and Al0.00010g/L-0.00030 g/L, Fe 0.00010 g/L-0.00030 g/L.

4. The method of claim 1, wherein the method comprises the following steps: the element concentrations in the 6N-grade magnesium sulfate solution are respectively as follows: cl 0.0000010 g/L-0.0000030 g/L, Si 0.0000010 g/L-0.0000030 g/L, As0.0000010 g/L-0.0000030 g/L, Na 0.0000010 g/L-0.0000050 g/L, K0.0000010g/L-0.0000050 g/L, Mg 58.0.0 g/L-62.0 g/L, Ca 0.000010 g/L-0.000050 g/L, Pb0.0000010g/L-0.0000030 g/L, Al 0.0000010.0000010 g/L-0.0000030 g/L, Fe 0.0000010.0000010 g/L-0.0000030 g/L.

Technical Field

The invention relates to a method for preparing a 6N-grade magnesium sulfate solution, in particular to a method for preparing a 6N-grade magnesium sulfate solution by taking a 4N-grade magnesium sulfate solution as a feed liquid and C272 as an extracting agent, separating and removing metal elements such as sodium, potassium, calcium, lead, aluminum, iron and the like in the feed liquid and non-metal elements such as chlorine, silicon, arsenic and the like. The invention belongs to the technical field of preparation of 6N-grade magnesium sulfate.

Background

The bittern is an important resource for extracting magnesium, and mainly contains metal elements of magnesium, sodium, potassium, calcium, aluminum and iron, nonmetal elements of sulfur (sulfate radical) and chlorine (chloride ion), and trace elements of lead, cadmium, silicon, arsenic and the like. Currently, the purity of magnesium sulfate extracted from magnesium-containing brine can only reach 3N grade at most, and the purity of magnesium sulfate extracted from other magnesium-containing primary raw materials (magnesium ore) is 2N grade generally. The existing method for preparing 6N-grade magnesium sulfate uses 2N-grade magnesium sulfate (industrial grade) as a raw material. Therefore, no method for preparing 6N grade magnesium sulfate from magnesium-containing brine exists at present. The method for indirectly preparing the 6N-grade magnesium sulfate has the defects of long process, low magnesium yield, high production cost and the like.

Aiming at the defects that the prior method for preparing 6N-grade magnesium sulfate from magnesium-containing brine does not exist, but the method for indirectly preparing 6N-grade magnesium sulfate has long flow, low magnesium yield, high production cost and the like, the invention establishes the method for efficiently separating metal and nonmetal impurities in 4N-grade magnesium sulfate to prepare the 6N-grade magnesium sulfate solution.

Disclosure of Invention

The invention provides a method for preparing a 6N-grade magnesium sulfate solution, which aims at the method for preparing 6N-grade magnesium sulfate which is not available, and provides a method for preparing the 6N-grade magnesium sulfate solution by taking a 4N-grade magnesium sulfate solution as a feed liquid.

The invention discloses a method for preparing a 6N-grade magnesium sulfate solution, which takes a 4N-grade magnesium sulfate solution as a feed liquid and di (2,4, 4-trimethylpentyl) phosphonic acid (C272 or Cyanex272 for short) as an extracting agent, separates and removes metal elements such as sodium, potassium, calcium, lead, aluminum, iron and the like in the feed liquid, and separates and removes non-metal elements such as chlorine, silicon, arsenic and the like to prepare the 6N-grade magnesium sulfate solution.

The invention relates to a method for preparing 6N-grade magnesium sulfate solution, which consists of 3 steps, namely full-load fractional extraction separation NaKMg/MgCaPbAlFe, full-load fractional extraction separation NaK/Mg and fractional extraction separation Mg/CaPbAlFe; the extraction section of full-load fractionation, extraction and separation NaKMg/MgCaPbAlFe realizes the separation of NaKMg/CaPbAlFe, and the washing section realizes the separation of NaK/MgCaPbAlFe; the method is characterized in that NaKMg/MgCaPbAlFe is separated by full-load fractionation extraction, a balanced loaded C272 organic phase obtained by separating NaK/Mg feeding grade by full-load fractionation extraction is used as an extraction organic phase, and a balanced aqueous phase obtained by separating Mg/CaPbAlFe feeding grade by fractionation extraction is used as a detergent. Full-load fractionation, extraction and separation of NaK/Mg and fractionation, extraction and separation of Mg/CaPbAlFe are directly connected in series; 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/CaPbAlFe by fractional extraction, and directly enters the 1 st stage for separating Mg/CaPbAlFe by fractional extraction; the 1 st stage outlet aqueous phase of the Mg/CaPbAlFe separation by fractional extraction is used as a washing agent for full-load fractional extraction separation of NaK/Mg.

The method for preparing the 6N-grade magnesium sulfate solution comprises the following 3 steps:

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

Step 1 is full-load fractionation, extraction and separation of NaKMg/MgCaPbAlFe, the extraction section realizes the separation of NaKMg/CaPbAlFe, and the washing section realizes the separation of NaK/MgCaPbAlFe. And (3) taking a balanced loaded C272 organic phase obtained from the feed stage of the NaK/Mg full-load fractional extraction system in the step 2 as an extraction organic phase, 4N-grade magnesium sulfate as a feed liquid, and taking a balanced water phase obtained from the feed stage of the Mg/CaPbAlFe fractional extraction system in the step 3 as a detergent. The equilibrium loaded C272 organic phase obtained from the feed stage of the NaK/Mg full-load fractionation extraction system in the step 2 enters the NaKMg/MgCaPbAlFe full-load fractionation extraction system from the 1 st stage, the 4N-stage magnesium sulfate enters the NaKMg/MgCaPbAlFe full-load fractionation extraction system from the feed stage, and the equilibrium aqueous phase obtained from the feed stage of the Mg/CaPbAlFe fractionation extraction system in the step 3 enters the NaKMg/MgCaPbAlFe full-load fractionation extraction system from the last stage 1. Obtaining a magnesium sulfate solution containing Na, K, Cl, Si and As from the water phase at the 1 st level outlet of the NaKMg/MgCaPbAlFe full-load fractional extraction system, and using the magnesium sulfate solution As a feed liquid for full-load fractional extraction and separation of NaK/Mg in the step 2; and (3) obtaining a C272 organic phase loaded with Mg-Ca-Pb-Al-Fe from the last 1-stage outlet organic phase of the NaKMg/MgCaPbAlFe full-load fractional extraction system, and using the C272 organic phase as feed liquid for fractional extraction and separation of Mg/CaPbAlFe 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 chlorine, silicon and arsenic in the magnesium sulfate solution. An ammonia saponification C272 organic phase is used As an extraction organic phase, a magnesium sulfate solution containing Na, K, Cl, Si and As, which is obtained by full-load NaKMg/MgCaPbAlFe full-load fractionation of an extraction system at the 1 st-stage outlet water phase in the step 1, is used As a feed liquid, and a 6N-stage magnesium sulfate solution which is obtained by the Mg/CaPbAlFe fractionation of the extraction system at the 1 st-stage outlet water phase in the step 3 is used As a detergent. The ammoniacal saponification C272 organic phase enters a NaK/Mg full-load fractionation extraction system from the 1 st level, a magnesium sulfate solution containing Na, K, Cl, Si and As obtained from the 1 st level outlet aqueous phase of the NaKMg/MgCaPbAlFe full-load fractionation extraction system of the step 1 enters the NaK/Mg full-load fractionation extraction system from a feeding level, and a 6N level magnesium sulfate solution obtained from the 1 st level outlet aqueous phase of the Mg/CaPbAlFe fractionation extraction system of the step 3 enters the NaK/Mg full-load fractionation extraction system from the last 1 level. Obtaining a mixture solution containing sodium, potassium, chlorine, silicon and arsenic from the water phase at the 1 st stage outlet of a NaK/Mg full-load fractional extraction system; separating a balanced load C272 organic phase of a feed grade of a NaK/Mg full-load fractional extraction system, and using the balanced load C272 organic phase as an extraction organic phase for full-load fractional extraction separation of NaKMg/MgCaPbAlFe in the step 1; and obtaining a C272 organic phase loaded with magnesium from the organic phase at the outlet of the last stage 1 of the NaK/Mg full-load fractional extraction system, and using the C272 organic phase as an extraction organic phase for fractional extraction and separation of Mg/CaPbAlFe in the step 3.

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

And 3, fractionating, extracting and separating Mg/CaPbAlFe to realize the separation of magnesium from calcium, lead, aluminum and iron. Taking a C272 organic phase loaded with magnesium obtained from the last stage 1 of the NaK/Mg full-load fractionation extraction system in the step 2 as an extraction organic phase, taking a C272 organic phase loaded with magnesium, calcium, lead, aluminum and iron obtained from the last stage 1 of the NaKMg/MgCaPbAlFe full-load fractionation extraction system in the step 1 as a feed liquid, and taking 2.5mol/L sulfuric acid as a washing acid. The C272 organic phase loaded with magnesium and obtained from the last level 1 of the NaK/Mg full-load fractionation extraction system in the step 2 enters the Mg/CaPbAlFe fractionation extraction system from the level 1, the C272 organic phase loaded with magnesium, calcium, lead, aluminum and iron and obtained from the last level 1 of the NaKMg/MgCaPbAlFe full-load fractionation extraction system in the step 1 enters the Mg/CaPbAlFe fractionation extraction system from the feeding level, and 2.5mol/L sulfuric acid washing acid enters the Mg/CaPbAlFe fractionation extraction system from the last level 1. Obtaining a target product 6N-grade magnesium sulfate solution from a 1 st grade outlet water phase of the Mg/CaPbAlFe fractional extraction system, and taking the 6N-grade magnesium sulfate 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/CaPbAlFe fractional extraction system to be used as a detergent for separating NaKMg/MgCaPbAlFe by full-load fractional extraction in the step 1; and obtaining a C272 organic phase loaded with calcium, lead, aluminum and iron from the final level 1 outlet organic phase of the Mg/CaPbAlFe fractional extraction system, and recovering valuable elements after back extraction.

The C272 organic phase is a sulfonated kerosene solution of C272, wherein the concentration of the C272 is 1.0 mol/L. When used, the C272 organic phase is saponified with aqueous ammonia to obtain an ammonolyzed C272 organic phase.

The element concentrations in the 4N-grade magnesium sulfate solution are respectively as follows: cl 0.00010 g/L-0.00050 g/L, Si0.00010g/L-0.00030 g/L, As 0.00010.00010 g/L-0.00030 g/L, Na 0.00010.00010 g/L-0.00070 g/L, K0.00010g/L-0.00050 g/L, Mg 58.0.0 g/L-62.0 g/L, Ca 0.0010.0010 g/L-0.0050 g/L, Pb0.00010g/L-0.00030 g/L, Al 0.00010.00010 g/L-0.00030 g/L/L, Fe 0.00010.00010 g/L-0.00030 g/L.

The element concentrations in the 6N-grade magnesium sulfate solution are respectively as follows: cl 0.0000010 g/L-0.0000030 g/L, Si 0.0000010 g/L-0.0000030 g/L, As 0.0000010.0000010 g/L-0.0000030 g/L, Na 0.0000010.0000010 g/L-0.0000050 g/L, K0.0000010 g/L-0.0000050 g/L, Mg 58.0.0 g/L-62.0 g/L, Ca 0.000010.000010 g/L-0.000050 g/L, Pb 0.0000010.0000010 g/L-0.0000030 g/L, Al 0.0000010.0000010 g/L-0.0000030 g/L, Fe0.0000010g/L-0.0000030 g/L.

The invention has the beneficial effects that: 1) and preparing a 6N-grade magnesium sulfate solution by using the 4N-grade magnesium sulfate solution as a feed liquid. After the 6N-grade magnesium sulfate solution is subjected to post-treatment such as concentration crystallization or precipitation, a series of 6N-grade magnesium-containing compounds such as 6N-grade magnesium sulfate crystals and 6N-grade magnesium phosphate crystals can be obtained. 2) The product purity is high, and the yield of magnesium is high: the purity of the 6N-grade magnesium sulfate solution of the target product is 99.99992-99.99998%, and the yield of magnesium in the 4N-grade magnesium sulfate solution is 95-97%. 3) The 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/CaPbAlFe by fractional extraction, and directly enters the 1 st stage of separating Mg/CaPbAlFe by fractional extraction, so that saponified alkali for separating Mg/CaPbAlFe by fractional extraction is saved. The water phase at the 1 st level outlet for separating Mg/CaPbAlFe by fractional extraction is used as a detergent for separating NaK/Mg by full-load fractional extraction, so that the washing acid for separating NaK/Mg by full-load fractional extraction is saved. 4) The separation efficiency is high: and 3 separation sections (full-load fractionation extraction separation NaKMg/MgCaPbAlFe, full-load fractionation extraction separation NaK/Mg, fractionation extraction separation Mg/CaPbAlFe) separate and remove metal impurities such as sodium, potassium, calcium, lead, aluminum, iron and the like and non-metal impurities such as chlorine, silicon, arsenic and the like in the 4N-grade magnesium sulfate. 5) The process flow is short: the process for the preparation of 6N grade magnesium sulfate from 4N grade magnesium sulfate consists of 3 separation stages. The method is characterized in that NaKMg/MgCaPbAlFe is separated by full-load fractionation and extraction, and a balanced loaded C272 organic phase obtained by full-load fractionation, extraction and separation of NaK/Mg feeding grade is used as an extraction organic phase, so that a saponification section is not needed for full-load fractionation, extraction and separation of NaKMg/MgCaPbAlFe; the equilibrium water phase obtained by fractionating, extracting and separating the Mg/CaPbAlFe feeding grade is a detergent, so that a stripping section is not needed for fully loading, fractionating, extracting and separating NaKMg/MgCaPbAlFe. The NaKMg/MgCaPbAlFe full-load fractional extraction separation and the NaK/Mg full-load fractional extraction separation share a saponification section. The outlet organic phase loaded with NaK/Mg separated by fractional extraction is used as the extraction organic phase for separating Mg/CaPbAlFe by fractional extraction, so that the saponification section is not needed for separating Mg/CaPbAlFe 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/CaPbAlFe, so that a back-extraction section is not needed for separating the NaK/Mg by the full-load fractional extraction. 6) The production cost is low: high separation efficiency, short process flow and less reagent consumption.

Drawings

FIG. 1 is a schematic process flow diagram of a process for preparing a 6N grade magnesium sulfate solution according to the present invention;

in FIG. 1, LOP denotes the loaded organic phase; w represents a detergent; 6N Mg represents a 6N grade magnesium sulfate solution.

Detailed Description

A method of preparing a 6N grade magnesium sulfate solution according to the present invention is further described below with reference to specific examples.