WO2024045531A1 - Method for treating magnesium-containing waste liquid - Google Patents

Method for treating magnesium-containing waste liquid Download PDF

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Publication number
WO2024045531A1
WO2024045531A1 PCT/CN2023/079349 CN2023079349W WO2024045531A1 WO 2024045531 A1 WO2024045531 A1 WO 2024045531A1 CN 2023079349 W CN2023079349 W CN 2023079349W WO 2024045531 A1 WO2024045531 A1 WO 2024045531A1
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magnesium
solid
waste liquid
containing waste
treating
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PCT/CN2023/079349
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French (fr)
Chinese (zh)
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曾志佳
李长东
阮丁山
陈若葵
乔延超
毛清敏
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广东邦普循环科技有限公司
湖南邦普循环科技有限公司
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Publication of WO2024045531A1 publication Critical patent/WO2024045531A1/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00—Compounds of magnesium
    • C01F5/24—Magnesium carbonates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/02—Oxides or hydroxides
    • C01F11/08—Oxides or hydroxides by reduction of sulfates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/46—Sulfates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00—Compounds of magnesium
    • C01F5/02—Magnesia
    • C01F5/06—Magnesia by thermal decomposition of magnesium compounds
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • C01P2006/82—Compositional purity water content

Definitions

  • the invention belongs to the technical field of wastewater treatment, and specifically relates to a method for treating magnesium-containing waste liquid.
  • the sulfuric acid leaching process is a commonly used method to extract valuable metals.
  • sulfuric acid is used to leach valuable metals such as nickel and cobalt from the ore.
  • a refined magnesium-containing sodium sulfate solution is obtained.
  • Magnesium oxide is then used to precipitate cobalt.
  • the solution contains a large amount of magnesium, and then After removing other metals, magnesium-containing sodium sulfate waste liquid is obtained.
  • the above-mentioned treatment method for magnesium-containing waste liquid is often to directly add sodium hydroxide and sodium carbonate to the magnesium-containing waste liquid to obtain magnesium hydroxide/basic magnesium carbonate, and then roast the product into magnesium oxide and sell it externally. ; Or evaporate and concentrate the magnesium-containing waste liquid, freeze and crystallize, and carry out salt separation and purification through the above method to obtain magnesium sulfate and sodium sulfate crystals, and then further prepare other magnesium salts.
  • the above method has the problems of high cost of raw materials and poor economic benefits; evaporation and crystallization, salt separation and purification, easy to form double salts, making it difficult to ensure the quality of the magnesium sulfate and sodium sulfate crystals obtained.
  • the present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a treatment method for magnesium-containing waste liquid to prepare high-purity magnesium salt.
  • step S2 Beat the solid phase residue obtained in step S1 and carbonize it once, perform solid-liquid separation on the carbonized product, and collect the liquid phase components;
  • step S3 Pyrolyze the liquid phase components obtained in step S2, conduct solid-liquid separation of the pyrolysis products, and collect the solid phase products;
  • step S4 Carry out secondary carbonization of the solid phase product obtained in step S3, collect the liquid phase components of the carbonized product, and prepare a refined magnesium bicarbonate solution;
  • the magnesium precipitating agent includes at least one of calcium oxide and calcium hydroxide
  • the primary carbonization and secondary carbonization are both the contact between reactants and carbon dioxide.
  • step S1 magnesium hydroxide and calcium sulfate hemihydrate are obtained by controlling the addition of calcium oxide or calcium hydroxide, and the filter residue obtained by filtration is calcium sulfate dihydrate and magnesium hydroxide;
  • step S2 a magnesium bicarbonate solution containing a small amount of calcium bicarbonate is obtained through one carbonization.
  • step S3 the magnesium bicarbonate solution in the liquid phase component separated by filtration in step S2 is pyrolyzed to obtain basic magnesium carbonate (magnesium salt).
  • the magnesium salt enters the solution preferentially, and the magnesium in the solution The content is getting higher and higher, the calcium and magnesium are separated, and the magnesium bicarbonate refined liquid is obtained.
  • step S1 of the present invention the calcium sulfate hemihydrate obtained by using a magnesium precipitation agent has good particle size, good filtration performance, and low attached water entrained on the surface, thereby reducing the moisture content of the entire product. , reducing the entrainment of impurities, thereby reducing the amount of product washing water and improving product quality; it can also reduce the subsequent drying costs of the product.
  • the purpose of primary carbonization is to convert magnesium hydroxide into magnesium bicarbonate solution and achieve separation from solid phase calcium sulfate. In this process, a small amount of calcium will enter the solution. Secondary carbonization removes calcium to obtain refined magnesium bicarbonate solution. Secondary carbonization Can remove impurities such as calcium.
  • the present invention uses secondary carbonization to realize the extraction of magnesium and the separation of magnesium and calcium, and effectively recover and produce high-purity magnesium salts. It also realizes the fixation and utilization of carbon dioxide, and effectively recovers and produces high-purity magnesium salts.
  • the mixing includes feed mixing by a peristaltic pump.
  • the feeding speed of the peristaltic pump is 0.001-0.009 mol/min on a molar ratio basis.
  • the feeding speed is too fast, it will cause agglomeration when the powder enters the solution. After the surface of the agglomerates participates in the reaction, it will be covered by the generated precipitate, so that the materials inside will no longer react and reduce the reaction efficiency.
  • the molar ratio of Mg 2+ in the magnesium-containing wastewater and the magnesium precipitation agent is 1: (1.05-1.1).
  • Adding the magnesium precipitating agent according to the above ratio can ensure the complete precipitation of magnesium. At the same time, it can prevent the magnesium precipitating agent from entering the product and increasing the impurity content of the product caused by excessive use of the magnesium precipitating agent.
  • the mixing includes stirring and mixing.
  • the stirring and mixing speed is 50-300 r/min.
  • the particle size and crystal form of calcium sulfate hemihydrate are guaranteed, thereby ensuring better filtration performance and reducing the amount of water used to wash the filter residue.
  • the particle size Dv50 of the calcium sulfate hemihydrate is 50-80 ⁇ m.
  • step S1 the main component of the filtrate obtained after the solid-liquid separation is sodium sulfate.
  • Yuanming powder After the above-mentioned sodium sulfate is evaporated and crystallized, Yuanming powder can be obtained, which can be used for external sales.
  • step S2 the solid content of the slurry obtained by beating is 10%-20%.
  • the slurry with the above solid content not only has good fluidity, but also does not introduce too much water and does not increase the subsequent processing steps.
  • the pH value of the system after primary carbonization is 7.0-7.5.
  • the pyrolysis temperature is 60-65°C.
  • the termination condition of the secondary carbonization is that the concentration change rate of Mg 2+ in the carbonization liquid is ⁇ 0.01g/L.
  • the carbonization is stopped, and the obtained carbonized liquid is a refined magnesium bicarbonate liquid.
  • step S4 also includes pyrolysis of the magnesium bicarbonate refined liquid.
  • the pyrolysis temperature of the magnesium bicarbonate refined liquid is 90-95°C.
  • the pyrolysis time of the magnesium bicarbonate refined liquid is 1-2 h.
  • basic magnesium carbonate is obtained after pyrolysis of the magnesium bicarbonate refined liquid.
  • the method further includes drying and roasting the basic magnesium carbonate to obtain activated magnesium oxide.
  • the carbon dioxide generated during the roasting process can be recycled into the primary carbonization process and the secondary carbonization process.
  • step S2 further includes pyrolytic reduction of the filter residue obtained by solid-liquid separation into the magnesium precipitating agent.
  • the filter residue includes calcium sulfate.
  • the pyrolysis reduction further includes drying the filter residue.
  • the drying temperature is 150-250°C.
  • the reducing agent used in the pyrolysis reduction of the filter residue includes coke.
  • the temperature of the pyrolysis reduction is 1000-1300°C.
  • the above method can realize the recycling of magnesium precipitating agent, greatly save the consumption of raw and auxiliary materials, and realize circular economy.
  • Figure 1 is a process flow chart for the treatment of magnesium-containing waste liquid in Embodiment 1 of the present invention.
  • This embodiment discloses a method for treating magnesium-containing waste liquid. The specific steps are:
  • step S2 Control the solid-to-liquid ratio of calcium sulfate dihydrate and magnesium hydroxide in step S1 to 15%, add water to beat, and introduce carbon dioxide to perform primary carbonization at 25°C.
  • the filter cake component is mainly calcium sulfate dihydrate, and the filtrate It is magnesium bicarbonate and a small amount of residual calcium bicarbonate.
  • the test results of the primary carbonization filtrate are shown in Table 3.
  • Calcium sulfate dihydrate (gypsum) is dried at 200°C to obtain anhydrous calcium sulfate. The roasting temperature is controlled at 1200°C, and coke is added.
  • Coke gypsum 0.15:1
  • sulfuric acid can be prepared and calcium oxide/calcium hydroxide can be co-produced.
  • the test results of the obtained calcium oxide are shown in Table 6, which can be used as raw material to precipitate magnesium.
  • This embodiment discloses a method for treating magnesium-containing waste liquid. The specific steps are:
  • step S2 Control the solid-to-liquid ratio of calcium sulfate dihydrate and magnesium hydroxide in step S1 to 15%, add water to beat, and add carbon dioxide Carbon is carbonized once at 25°C. After filtration, the filter cake composition is mainly calcium sulfate dihydrate, and the filtrate is magnesium bicarbonate and a small amount of residual calcium bicarbonate. The test results of the primary carbonization filtrate are shown in Table 3.
  • Calcium sulfate dihydrate (gypsum) is dried at 180°C to obtain anhydrous calcium sulfate, control the roasting temperature at 1250°C, add coke, coke: gypsum 0.18:1, and decompose through reduction roasting to prepare sulfuric acid and co-produce calcium oxide/calcium hydroxide to obtain
  • the test results of calcium oxide are shown in Table 6, which are used as raw materials to precipitate magnesium.
  • This embodiment discloses a method for treating magnesium-containing waste liquid. The specific steps are:
  • step S2 Control the solid-to-liquid ratio of calcium sulfate dihydrate and magnesium hydroxide in step S1 to 10%, add water to beat, and introduce carbon dioxide to perform primary carbonization at 25°C.
  • the filter cake component is mainly calcium sulfate dihydrate, and the filtrate It is magnesium bicarbonate and a small amount of residual calcium bicarbonate.
  • the test results of the primary carbonization filtrate are shown in Table 3.
  • Calcium sulfate dihydrate (gypsum) is dried at 250°C to obtain anhydrous calcium sulfate. The roasting temperature is controlled at 1300°C, and coke is added.
  • Coke gypsum 0.2:1
  • sulfuric acid can be prepared and calcium oxide/calcium hydroxide can be co-produced.
  • the test results of the obtained calcium oxide are shown in Table 6, which can be used as raw material to precipitate magnesium.
  • This embodiment discloses a method for treating magnesium-containing waste liquid.
  • the difference between this embodiment and Example 1 is that in step S1, the temperature of the stirring reaction is 100°C, and the other conditions are the same.
  • This comparative example discloses a method for treating magnesium-containing waste liquid.
  • the difference between this comparative example and Example 1 is that the stirring reaction temperature in step S1 in this comparative example is 85°C, and the other conditions are the same as in Example 1.
  • This comparative example discloses a method for treating magnesium-containing waste liquid.
  • the difference between this comparative example and Example 1 is that this comparative example
  • the stirring reaction temperature in step S1 is 90°C, and the other conditions are the same as in Example 1.
  • This test example tests the magnesium sedimentation filter residue in step S1 in Example 1 and Comparative Examples 1-2.
  • the test results are shown in Table 2.
  • Example 2 in Table 1 calcium hydroxide slurry is added at a feeding ratio of 1:1. Since the reaction ratio cannot reach 100% and there will be trace losses during the process, the hydroxide radicals entering the magnesium-containing waste liquid cannot reach the concentration required to completely precipitate magnesium. , so the concentration of magnesium in the filtrate is higher than that of the other two groups of examples.
  • the reaction temperatures in Comparative Example 1 and Comparative Example 2 are 85°C and 90°C respectively.
  • the filter residue product is mainly calcium sulfate dihydrate, and its crystal water and surface water are both higher than those of the filter residue obtained in Example 1.
  • the surface The content of entrained impurities is high, and the sodium content is more than 1.5%;
  • the reaction temperature of Example 1 is 95°C, the filter residue product is mainly hemihydrate gypsum, and its crystal water and surface water content are both lower than Comparative Example 1 and Comparative Example 2.
  • the sodium content It is only 0.1%, which is also much lower than Comparative Example 1 and Comparative Example 2.
  • This test example tests the secondary carbonization filtrate in step S3 of Example 1-3.
  • the test results are shown in Table 4.
  • the filter cake is beaten and carbonized according to different solid-liquid ratios.
  • the magnesium content involved in the reaction is basically the same. The lower the solid-liquid ratio, the higher the magnesium concentration in the filtrate after carbonization. In Example 3, the solid-liquid ratio is carbonized at 10%, and the magnesium in the filtrate is The recovery rate is the highest, and its process is the best in terms of recovery efficiency among the examples.
  • This test example tests the primary carbonization filtrate in step S3 of Example 1-3.
  • the test results are shown in Table 5.
  • the surface water content of the calcium sulfate dihydrate obtained by the present invention is low, below 7%.
  • the moisture content of conventional calcium sulfate dihydrate is above 20%. Therefore, the attached water entrained on the surface of the calcium sulfate dihydrate of the present invention is low, and the entire surface of the calcium sulfate dihydrate has a low moisture content.
  • the moisture content of the product decreases, reducing the entrainment of impurities, thereby reducing the amount of product washing water and improving product quality; it can also reduce the cost of drying subsequent products.
  • the above calcium oxide is obtained by the pyrolysis reduction of calcium sulfate. It is suitable for industrial calcium oxide standards for Class I chemical synthesis in HG/T 4205-2011.
  • the calcium oxide content is ⁇ 92% and the magnesium oxide content is ⁇ 1.5%. It can be used as a magnesium precipitating agent. Add it to magnesium-containing waste liquid for reuse.

Abstract

Disclosed is a method for treating magnesium-containing waste liquid, comprising the following steps: S1, mixing a magnesium precipitation agent with magnesium-containing wastewater, performing solid-liquid separation, and collecting solid-phase residues, the temperature of the mixing being 95-100°C, and the magnesium-containing wastewater containing Mg2+ and SO4 2-; S2, beating the solid-phase residues obtained in step S1 and performing primary carbonization on same, performing solid-liquid separation on the carbonized product, and collecting a liquid-phase component; S3, pyrolyzing the liquid-phase component obtained in step S2, performing solid-liquid separation on the pyrolysis product, and collecting a solid-phase product; and S4, performing secondary carbonization on the solid-phase product obtained in step S3, and collecting a liquid-phase component of the carbonized product, so as to prepare a magnesium bicarbonate refined solution. The magnesium precipitation agent comprises at least one of calcium oxide and calcium hydroxide; and the primary carbonization and the secondary carbonization both make a reactant to be in contact with carbon dioxide. The method for treating magnesium-containing wastewater of the present invention can effectively recover and produce high-purity magnesium salts.

Description

一种含镁废液的处理方法A kind of treatment method of magnesium-containing waste liquid 技术领域Technical field
本发明属于废水处理技术领域，具体涉及一种含镁废液的处理方法。The invention belongs to the technical field of wastewater treatment, and specifically relates to a method for treating magnesium-containing waste liquid.
背景技术Background technique
在传统湿法冶金过程中，硫酸浸出工艺是常用的提炼有价金属的方法。在镍钴湿法冶炼中，采用硫酸将矿石中的镍钴等有价金属浸出，经过萃取分离提纯后得到精制含镁硫酸钠溶液，随后使用氧化镁沉钴，溶液中含有大量的镁，再经过去除其他金属后，得到含镁硫酸钠废液。In the traditional hydrometallurgical process, the sulfuric acid leaching process is a commonly used method to extract valuable metals. In the nickel and cobalt hydrometallurgy, sulfuric acid is used to leach valuable metals such as nickel and cobalt from the ore. After extraction, separation and purification, a refined magnesium-containing sodium sulfate solution is obtained. Magnesium oxide is then used to precipitate cobalt. The solution contains a large amount of magnesium, and then After removing other metals, magnesium-containing sodium sulfate waste liquid is obtained.
目前，针对上述含镁废液的处理方法，往往是直接向含镁废液中加入氢氧化钠和碳酸钠，从而得到氢氧化镁/碱式碳酸镁，然后将产物焙烧成氧化镁并外售；或者将含镁废液蒸发浓缩，冷冻结晶，通过以上方法进行分盐提纯，得到硫酸镁及硫酸钠晶体，再进一步制备成其他镁盐。但上述方法存在原辅料成本高，经济效益差；蒸发结晶分盐提纯，易形成复盐，使得到的硫酸镁及硫酸钠晶体的品质也较难得到保证的问题。At present, the above-mentioned treatment method for magnesium-containing waste liquid is often to directly add sodium hydroxide and sodium carbonate to the magnesium-containing waste liquid to obtain magnesium hydroxide/basic magnesium carbonate, and then roast the product into magnesium oxide and sell it externally. ; Or evaporate and concentrate the magnesium-containing waste liquid, freeze and crystallize, and carry out salt separation and purification through the above method to obtain magnesium sulfate and sodium sulfate crystals, and then further prepare other magnesium salts. However, the above method has the problems of high cost of raw materials and poor economic benefits; evaporation and crystallization, salt separation and purification, easy to form double salts, making it difficult to ensure the quality of the magnesium sulfate and sodium sulfate crystals obtained.
因此，开发一种从含镁废液中回收高纯度镁盐的处理方法是目前的当务之急。Therefore, developing a treatment method for recovering high-purity magnesium salts from magnesium-containing waste liquids is a top priority.
发明内容Contents of the invention
本发明旨在至少解决现有技术中存在的技术问题之一。为此，本发明提出一种含镁废液的处理方法，以制备得到高纯镁盐。The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a treatment method for magnesium-containing waste liquid to prepare high-purity magnesium salt.
根据本发明的第一方面实施例的一种含镁废液的处理方法，包括如下步骤：A method for treating magnesium-containing waste liquid according to the first embodiment of the present invention includes the following steps:
S1：将沉镁剂和含镁废水混合，固液分离，收集固相渣；所述混合的温度为95-100℃；所述含镁废水中含有Mg2+和SO4 2-；S1: Mix the magnesium precipitation agent and magnesium-containing wastewater, separate the solid and liquid, and collect the solid phase slag; the mixing temperature is 95-100°C; the magnesium-containing wastewater contains Mg 2+ and SO 4 2- ;
S2：将步骤S1所得固相渣进行打浆、一次碳化，对碳化产物进行固液分离，收集液相组分；S2: Beat the solid phase residue obtained in step S1 and carbonize it once, perform solid-liquid separation on the carbonized product, and collect the liquid phase components;
S3：将步骤S2所得液相组分进行热解，并对热解产物进行固液分离，收集固相产物；S3: Pyrolyze the liquid phase components obtained in step S2, conduct solid-liquid separation of the pyrolysis products, and collect the solid phase products;
S4：将步骤S3所得固相产物进行二次碳化，收集碳化产物的液相组分，制得碳酸氢镁精制液；S4: Carry out secondary carbonization of the solid phase product obtained in step S3, collect the liquid phase components of the carbonized product, and prepare a refined magnesium bicarbonate solution;
所述沉镁剂包括氧化钙和氢氧化钙中的至少一种；The magnesium precipitating agent includes at least one of calcium oxide and calcium hydroxide;
所述一次碳化和二次碳化均为反应物和二氧化碳接触。The primary carbonization and secondary carbonization are both the contact between reactants and carbon dioxide.
本发明的原理如下： The principle of the present invention is as follows:
步骤S1中，通过控制加入氧化钙或氢氧化钙得到氢氧化镁及半水硫酸钙，过滤得到的滤渣为二水硫酸钙及及氢氧化镁；In step S1, magnesium hydroxide and calcium sulfate hemihydrate are obtained by controlling the addition of calcium oxide or calcium hydroxide, and the filter residue obtained by filtration is calcium sulfate dihydrate and magnesium hydroxide;
Ca(OH)2+MgSO4+0.5H2O＝＝CaSO4·0.5H2O+Mg(OH)2；Ca(OH) 2 +MgSO 4 +0.5H 2 O==CaSO 4 ·0.5H 2 O+Mg(OH) 2 ;
CaO+MgSO4+1.5H2O＝＝CaSO4·0.5H2O+Mg(OH)2；CaO+MgSO 4 +1.5H 2 O==CaSO 4 ·0.5H 2 O+Mg(OH) 2 ;
步骤S2中，通过一次碳化得到含少量碳酸氢钙的碳酸氢镁溶液，In step S2, a magnesium bicarbonate solution containing a small amount of calcium bicarbonate is obtained through one carbonization.
Mg(OH)2+2CO2＝＝Mg(HCO3)2；Mg(OH) 2 +2CO 2 ==Mg(HCO 3 ) 2 ;
步骤S3中，对步骤S2过滤分离后的液相组分中的碳酸氢镁溶液热解，得到碱式碳酸镁(镁盐)，二次碳化过程中，镁盐优先进入溶液，溶液中的镁的含量越来越高，实现钙镁分离，得到碳酸氢镁精制液。In step S3, the magnesium bicarbonate solution in the liquid phase component separated by filtration in step S2 is pyrolyzed to obtain basic magnesium carbonate (magnesium salt). During the secondary carbonization process, the magnesium salt enters the solution preferentially, and the magnesium in the solution The content is getting higher and higher, the calcium and magnesium are separated, and the magnesium bicarbonate refined liquid is obtained.
5Mg(HCO3)2＝4MgCO3·Mg(OH)2·4H2O+6CO2；5Mg(HCO 3 ) 2 =4MgCO 3 ·Mg(OH) 2 ·4H 2 O+6CO 2 ;
4MgCO3·Mg(OH)2·4H2O+CO2＝Mg(HCO3)2+3H2O；4MgCO 3 ·Mg(OH) 2 ·4H 2 O+CO 2 =Mg(HCO 3 ) 2 +3H 2 O;
根据本发明实施例的一种含镁废液的处理方法，至少具有以下有益效果：A method for treating magnesium-containing waste liquid according to an embodiment of the present invention has at least the following beneficial effects:
1、在不同温度下，石膏以不同的结晶产品及晶体状态存在，二水石膏在65℃开始释出结构水，但脱水速度较慢，在95-100℃下，可实现滤渣转变为半水石膏，同时避免因温度过高导致能耗增加，本发明中步骤S1利用沉镁剂得到的半水硫酸钙颗粒度好，过滤性能好，表面夹带的附着水低，进而整个产品的含水率下降，减少杂质的夹带，进而减少产品洗涤水用量，提高产品品质；同时还能减少后续生成物的烘干成本。1. At different temperatures, gypsum exists in different crystalline products and crystal states. Dihydrate gypsum begins to release structural water at 65°C, but the dehydration speed is slow. At 95-100°C, the filter residue can be transformed into semi-water. Gypsum, while avoiding an increase in energy consumption due to excessive temperature. In step S1 of the present invention, the calcium sulfate hemihydrate obtained by using a magnesium precipitation agent has good particle size, good filtration performance, and low attached water entrained on the surface, thereby reducing the moisture content of the entire product. , reducing the entrainment of impurities, thereby reducing the amount of product washing water and improving product quality; it can also reduce the subsequent drying costs of the product.
2、一次碳化是为了将氢氧化镁转化成碳酸氢镁溶液，实现与固相硫酸钙分离，这个过程会有少量钙进入溶液，二次碳化除钙，得到碳酸氢镁精制液，二次碳化可除去钙等杂质。2. The purpose of primary carbonization is to convert magnesium hydroxide into magnesium bicarbonate solution and achieve separation from solid phase calcium sulfate. In this process, a small amount of calcium will enter the solution. Secondary carbonization removes calcium to obtain refined magnesium bicarbonate solution. Secondary carbonization Can remove impurities such as calcium.
3、本发明用二次碳化实现了镁的提取及镁钙分离，有效回收及生产高纯镁盐，也实现了二氧化碳的固定及利用，有效回收及生产高纯镁盐。3. The present invention uses secondary carbonization to realize the extraction of magnesium and the separation of magnesium and calcium, and effectively recover and produce high-purity magnesium salts. It also realizes the fixation and utilization of carbon dioxide, and effectively recovers and produces high-purity magnesium salts.
根据本发明的一些实施例，所述混合包括通过蠕动泵进行加料混合。According to some embodiments of the invention, the mixing includes feed mixing by a peristaltic pump.
根据本发明的一些实施例，按摩尔比计，所述蠕动泵加料速度为0.001-0.009mol/min。According to some embodiments of the present invention, the feeding speed of the peristaltic pump is 0.001-0.009 mol/min on a molar ratio basis.
加料速度过快，会导致粉末进入溶液时产生团聚现象，团聚物表面参与反应后会被生成的沉淀覆盖，使内里的物料不再进行反应，降低反应效率。If the feeding speed is too fast, it will cause agglomeration when the powder enters the solution. After the surface of the agglomerates participates in the reaction, it will be covered by the generated precipitate, so that the materials inside will no longer react and reduce the reaction efficiency.
根据本发明的一些实施例，所述含镁废水中的Mg2+和所述沉镁剂的摩尔比为1：(1.05-1.1)。According to some embodiments of the present invention, the molar ratio of Mg 2+ in the magnesium-containing wastewater and the magnesium precipitation agent is 1: (1.05-1.1).
按上述比例加入沉镁剂可保证镁沉淀完全，同时可避免沉镁剂用量过多而导致的沉镁剂进入产品，增加产品的杂质含量。Adding the magnesium precipitating agent according to the above ratio can ensure the complete precipitation of magnesium. At the same time, it can prevent the magnesium precipitating agent from entering the product and increasing the impurity content of the product caused by excessive use of the magnesium precipitating agent.
根据本发明的一些实施例，所述混合包括搅拌混合。According to some embodiments of the invention, the mixing includes stirring and mixing.
根据本发明的一些实施例，所述搅拌混合的转速为50-300r/min。 According to some embodiments of the present invention, the stirring and mixing speed is 50-300 r/min.
在上述转速下，保证了半水硫酸钙的颗粒度和晶型，从而保证了更好的过滤性能，减少洗涤滤渣的水的用量。At the above-mentioned rotation speed, the particle size and crystal form of calcium sulfate hemihydrate are guaranteed, thereby ensuring better filtration performance and reducing the amount of water used to wash the filter residue.
根据本发明的一些实施例，所述半水硫酸钙的粒径Dv50为50-80μm。According to some embodiments of the present invention, the particle size Dv50 of the calcium sulfate hemihydrate is 50-80 μm.
根据本发明的一些实施例，步骤S1中，所述固液分离后得到的滤液的主要成分为硫酸钠。According to some embodiments of the present invention, in step S1, the main component of the filtrate obtained after the solid-liquid separation is sodium sulfate.
上述硫酸钠蒸发结晶后可制得元明粉，可用于外售。After the above-mentioned sodium sulfate is evaporated and crystallized, Yuanming powder can be obtained, which can be used for external sales.
根据本发明的一些实施例，步骤S2中，所述打浆得到的浆料的固含量为10％-20％。According to some embodiments of the present invention, in step S2, the solid content of the slurry obtained by beating is 10%-20%.
上述固含量下的浆料不仅具有较好的流动性，而且不会引入过多水量，不会增加后续处理的工序。The slurry with the above solid content not only has good fluidity, but also does not introduce too much water and does not increase the subsequent processing steps.
根据本发明的一些实施例，所述一次碳化后的体系的pH值为7.0-7.5。According to some embodiments of the present invention, the pH value of the system after primary carbonization is 7.0-7.5.
上述pH值下，保证了体系中的镁充分转化为碳酸氢镁。Under the above pH value, it is ensured that the magnesium in the system is fully converted into magnesium bicarbonate.
根据本发明的一些实施例，步骤S3中，所述热解的温度为60-65℃。According to some embodiments of the present invention, in step S3, the pyrolysis temperature is 60-65°C.
根据本发明的一些实施例，步骤S3中，所述二次碳化的终止条件为碳化液中的Mg2+的浓度变化率≤0.01g/L。According to some embodiments of the present invention, in step S3, the termination condition of the secondary carbonization is that the concentration change rate of Mg 2+ in the carbonization liquid is ≤0.01g/L.
当碳化液中Mg2+的浓度趋于稳定时，停止碳化，得到的碳化液为碳酸氢镁精制液。When the concentration of Mg 2+ in the carbonized liquid becomes stable, the carbonization is stopped, and the obtained carbonized liquid is a refined magnesium bicarbonate liquid.
根据本发明的一些实施例，步骤S4中，还包括对所述碳酸氢镁精制液热解。According to some embodiments of the present invention, step S4 also includes pyrolysis of the magnesium bicarbonate refined liquid.
根据本发明的一些实施例，所述碳酸氢镁精制液的热解温度为90-95℃。According to some embodiments of the present invention, the pyrolysis temperature of the magnesium bicarbonate refined liquid is 90-95°C.
根据本发明的一些实施例，所述碳酸氢镁精制液的热解时间为1-2h。According to some embodiments of the present invention, the pyrolysis time of the magnesium bicarbonate refined liquid is 1-2 h.
根据本发明的一些实施例，所述碳酸氢镁精制液热解后得到碱式碳酸镁。According to some embodiments of the present invention, basic magnesium carbonate is obtained after pyrolysis of the magnesium bicarbonate refined liquid.
根据本发明的一些实施例，还包括对所述碱式碳酸镁干燥、焙烧得到活性氧化镁。According to some embodiments of the present invention, the method further includes drying and roasting the basic magnesium carbonate to obtain activated magnesium oxide.
根据本发明的一些实施例，所述焙烧过程中产生的二氧化碳可回用于所述一次碳化过程和二次碳化过程。According to some embodiments of the present invention, the carbon dioxide generated during the roasting process can be recycled into the primary carbonization process and the secondary carbonization process.
根据本发明的一些实施例，步骤S2中，还包括对所述固液分离得到的滤渣热解还原为所述沉镁剂。According to some embodiments of the present invention, step S2 further includes pyrolytic reduction of the filter residue obtained by solid-liquid separation into the magnesium precipitating agent.
根据本发明的一些实施例，所述滤渣包括硫酸钙。According to some embodiments of the invention, the filter residue includes calcium sulfate.
根据本发明的一些实施例，所述热解还原前还包括对所述滤渣进行干燥。According to some embodiments of the present invention, the pyrolysis reduction further includes drying the filter residue.
根据本发明的一些实施例，所述干燥的温度为150-250℃。According to some embodiments of the present invention, the drying temperature is 150-250°C.
根据本发明的一些实施例，所述滤渣的热解还原使用的还原剂包括焦碳。According to some embodiments of the present invention, the reducing agent used in the pyrolysis reduction of the filter residue includes coke.
根据本发明的一些实施例，所述热解还原的温度为1000-1300℃。According to some embodiments of the present invention, the temperature of the pyrolysis reduction is 1000-1300°C.
根据本发明的一些实施例，按重量比计，所述热解还原的原料配比为，焦炭：硫酸钙＝(0.15-0.2)：1。According to some embodiments of the present invention, in terms of weight ratio, the raw material ratio for pyrolysis reduction is: coke: calcium sulfate = (0.15-0.2): 1.
上述方法可以实现沉镁剂的循环利用，大大节约原辅料的消耗，实现循环经济。 The above method can realize the recycling of magnesium precipitating agent, greatly save the consumption of raw and auxiliary materials, and realize circular economy.
附图说明Description of drawings
本发明的上述和/或附加的方面和优点从结合下面附图对实施例的描述中将变得明显和容易理解，其中：The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
图1是本发明实施例1中含镁废液的处理的工艺流程图。Figure 1 is a process flow chart for the treatment of magnesium-containing waste liquid in Embodiment 1 of the present invention.
具体实施方式Detailed ways
下面详细描述本发明的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，仅用于解释本发明，而不应理解为对本发明的限制。Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be understood as limiting the present invention.
实施例1Example 1
本实施例公开了一种含镁废液的处理方法，具体步骤为：This embodiment discloses a method for treating magnesium-containing waste liquid. The specific steps are:
S1：取含镁7g/L的废液；配置100g/L氢氧化钙浆料，按摩尔比1:1.05投料，用蠕动泵缓慢加料，加料速度为0.009mol/min，95℃搅拌反应1.5h，得到氢氧化镁和半水硫酸钙，半水硫酸钙在过滤分离时重新生成二水硫酸钙，过滤后，滤液检测结果如表1所示，主要成分为硫酸钠，对滤液进一步除杂作为元明粉。S1: Take the waste liquid containing 7g/L magnesium; prepare 100g/L calcium hydroxide slurry, add the material at a molar ratio of 1:1.05, slowly add the material with a peristaltic pump, the adding speed is 0.009mol/min, stir and react at 95°C for 1.5h , to obtain magnesium hydroxide and calcium sulfate hemihydrate. Calcium sulfate hemihydrate regenerates calcium sulfate dihydrate during filtration and separation. After filtration, the test results of the filtrate are shown in Table 1. The main component is sodium sulfate. The filtrate is further impurity removed as Yuanming powder.
S2：将步骤S1中的二水硫酸钙及氢氧化镁控制固液比为15％，加水打浆，通入二氧化碳在25℃进行一次碳化，过滤后，滤饼成分主要为二水硫酸钙，滤液为碳酸氢镁及残留少量碳酸氢钙，一次碳化滤液检测结果如表3所示，二水硫酸钙(石膏)经过200℃烘干得到无水硫酸钙，控制焙烧温度在1200℃，加入焦炭，焦碳：石膏0.15:1，经还原焙烧分解，可制备得到硫酸同时联产氧化钙/氢氧化钙，得到的氧化钙的检测结果如表6所示，作为原料回用于沉镁。S2: Control the solid-to-liquid ratio of calcium sulfate dihydrate and magnesium hydroxide in step S1 to 15%, add water to beat, and introduce carbon dioxide to perform primary carbonization at 25°C. After filtration, the filter cake component is mainly calcium sulfate dihydrate, and the filtrate It is magnesium bicarbonate and a small amount of residual calcium bicarbonate. The test results of the primary carbonization filtrate are shown in Table 3. Calcium sulfate dihydrate (gypsum) is dried at 200°C to obtain anhydrous calcium sulfate. The roasting temperature is controlled at 1200°C, and coke is added. Coke: gypsum 0.15:1, after reduction and roasting decomposition, sulfuric acid can be prepared and calcium oxide/calcium hydroxide can be co-produced. The test results of the obtained calcium oxide are shown in Table 6, which can be used as raw material to precipitate magnesium.
S3：一次碳化滤液热解得到碳酸镁沉淀，对碳酸镁沉淀在固液比20％下进行搅拌，二级碳化得到碳酸氢镁溶液，过滤后，二次碳化滤液检测结果如表4所示，热解二次碳化滤液后得到碱式碳酸镁，焙烧得到氧化镁，尾气二氧化碳进行回收。S3: The primary carbonization filtrate is pyrolyzed to obtain magnesium carbonate precipitate. The magnesium carbonate precipitate is stirred at a solid-to-liquid ratio of 20%. The secondary carbonization is performed to obtain a magnesium bicarbonate solution. After filtration, the test results of the secondary carbonization filtrate are shown in Table 4. After pyrolysis of the secondary carbonization filtrate, basic magnesium carbonate is obtained, which is roasted to obtain magnesium oxide, and the tail gas carbon dioxide is recovered.
本实施例中的含镁废液的处理的工艺流程图如图1所示。The process flow chart of the treatment of magnesium-containing waste liquid in this embodiment is shown in Figure 1.
实施例2Example 2
本实施例公开了一种含镁废液的处理方法，具体步骤为：This embodiment discloses a method for treating magnesium-containing waste liquid. The specific steps are:
S1：取含镁7g/L的废液；配置100g/L氢氧化钙浆料，按摩尔比1:1投料，用蠕动泵缓慢加料，加料速度为0.009mol/min，95℃搅拌反应1.5h，得到氢氧化镁和半水硫酸钙，半水硫酸钙在过滤分离时重新生成二水硫酸钙，过滤后，滤液检测结果如表1所示，主要成分为硫酸钠，对滤液进一步除杂作为元明粉。S1: Take the waste liquid containing 7g/L magnesium; prepare 100g/L calcium hydroxide slurry, add the material at a molar ratio of 1:1, slowly add the material with a peristaltic pump, the adding speed is 0.009mol/min, stir and react at 95°C for 1.5h , to obtain magnesium hydroxide and calcium sulfate hemihydrate. Calcium sulfate hemihydrate regenerates calcium sulfate dihydrate during filtration and separation. After filtration, the test results of the filtrate are shown in Table 1. The main component is sodium sulfate. The filtrate is further impurity removed as Yuanming powder.
S2：将步骤S1中的二水硫酸钙及氢氧化镁控制固液比为15％，加水打浆，通入二氧化 碳在25℃进行一次碳化，过滤后，滤饼成分主要为二水硫酸钙，滤液为碳酸氢镁及残留少量碳酸氢钙，一次碳化滤液检测结果如表3所示，二水硫酸钙(石膏)经过180℃烘干得到无水硫酸钙，控制焙烧温度在1250℃，加入焦炭，焦碳：石膏0.18:1，经还原焙烧分解，可制备得到硫酸同时联产氧化钙/氢氧化钙，得到的氧化钙的检测结果如表6所示，作为原料回用于沉镁。S2: Control the solid-to-liquid ratio of calcium sulfate dihydrate and magnesium hydroxide in step S1 to 15%, add water to beat, and add carbon dioxide Carbon is carbonized once at 25°C. After filtration, the filter cake composition is mainly calcium sulfate dihydrate, and the filtrate is magnesium bicarbonate and a small amount of residual calcium bicarbonate. The test results of the primary carbonization filtrate are shown in Table 3. Calcium sulfate dihydrate (gypsum) ) is dried at 180°C to obtain anhydrous calcium sulfate, control the roasting temperature at 1250°C, add coke, coke: gypsum 0.18:1, and decompose through reduction roasting to prepare sulfuric acid and co-produce calcium oxide/calcium hydroxide to obtain The test results of calcium oxide are shown in Table 6, which are used as raw materials to precipitate magnesium.
S3：一次碳化滤液热解得到碳酸镁沉淀，对碳酸镁沉淀在固液比15％下进行搅拌，二级碳化得到碳酸氢镁溶液，过滤后，二次碳化滤液检测结果如表4所示，热解二次碳化滤液后得到碱式碳酸镁，焙烧得到氧化镁，尾气二氧化碳进行回收。S3: The primary carbonization filtrate is pyrolyzed to obtain magnesium carbonate precipitate. The magnesium carbonate precipitate is stirred at a solid-to-liquid ratio of 15%. The secondary carbonization is performed to obtain a magnesium bicarbonate solution. After filtration, the test results of the secondary carbonization filtrate are shown in Table 4. After pyrolysis of the secondary carbonization filtrate, basic magnesium carbonate is obtained, which is roasted to obtain magnesium oxide, and the tail gas carbon dioxide is recovered.
实施例3Example 3
本实施例公开了一种含镁废液的处理方法，具体步骤为：This embodiment discloses a method for treating magnesium-containing waste liquid. The specific steps are:
S1：取含镁7g/L的废液；配置100g/L氢氧化钙浆料，按摩尔比1:1.1投料，用蠕动泵缓慢加料，加料速度为0.009mol/min，95℃搅拌反应1.5h，得到氢氧化镁和半水硫酸钙，半水硫酸钙在过滤分离时重新生成二水硫酸钙，过滤后，滤液检测结果如表1所示，主要成分为硫酸钠，对滤液进一步除杂作为元明粉。S1: Take the waste liquid containing 7g/L magnesium; prepare 100g/L calcium hydroxide slurry, add the material at a molar ratio of 1:1.1, slowly add the material with a peristaltic pump, the adding speed is 0.009mol/min, stir and react at 95°C for 1.5h , to obtain magnesium hydroxide and calcium sulfate hemihydrate. Calcium sulfate hemihydrate regenerates calcium sulfate dihydrate during filtration and separation. After filtration, the test results of the filtrate are shown in Table 1. The main component is sodium sulfate. The filtrate is further impurity removed as Yuanming powder.
S2：将步骤S1中的二水硫酸钙及氢氧化镁控制固液比为10％，加水打浆，通入二氧化碳在25℃进行一次碳化，过滤后，滤饼成分主要为二水硫酸钙，滤液为碳酸氢镁及残留少量碳酸氢钙，一次碳化滤液检测结果如表3所示，二水硫酸钙(石膏)经过250℃烘干得到无水硫酸钙，控制焙烧温度在1300℃，加入焦炭，焦碳：石膏0.2:1，经还原焙烧分解，可制备得到硫酸同时联产氧化钙/氢氧化钙，得到的氧化钙的检测结果如表6所示，作为原料回用于沉镁。S2: Control the solid-to-liquid ratio of calcium sulfate dihydrate and magnesium hydroxide in step S1 to 10%, add water to beat, and introduce carbon dioxide to perform primary carbonization at 25°C. After filtration, the filter cake component is mainly calcium sulfate dihydrate, and the filtrate It is magnesium bicarbonate and a small amount of residual calcium bicarbonate. The test results of the primary carbonization filtrate are shown in Table 3. Calcium sulfate dihydrate (gypsum) is dried at 250°C to obtain anhydrous calcium sulfate. The roasting temperature is controlled at 1300°C, and coke is added. Coke: gypsum 0.2:1, after reduction and roasting decomposition, sulfuric acid can be prepared and calcium oxide/calcium hydroxide can be co-produced. The test results of the obtained calcium oxide are shown in Table 6, which can be used as raw material to precipitate magnesium.
S3：一次碳化滤液热解得到碳酸镁沉淀，对碳酸镁沉淀在固液比10％下进行搅拌，二级碳化得到碳酸氢镁溶液，过滤后，二次碳化滤液检测结果如表4所示，热解二次碳化滤液后得到碱式碳酸镁，焙烧得到氧化镁，尾气二氧化碳进行回收。S3: The primary carbonization filtrate is pyrolyzed to obtain magnesium carbonate precipitate. The magnesium carbonate precipitate is stirred at a solid-to-liquid ratio of 10%. The secondary carbonization is performed to obtain a magnesium bicarbonate solution. After filtration, the test results of the secondary carbonization filtrate are shown in Table 4. After pyrolysis of the secondary carbonization filtrate, basic magnesium carbonate is obtained, which is roasted to obtain magnesium oxide, and the tail gas carbon dioxide is recovered.
实施例4Example 4
本实施例公开了一种含镁废液的处理方法，本实施例和实施例1的区别在于，步骤S1中，搅拌反应的温度为100℃，其余条件相同。This embodiment discloses a method for treating magnesium-containing waste liquid. The difference between this embodiment and Example 1 is that in step S1, the temperature of the stirring reaction is 100°C, and the other conditions are the same.
对比例1Comparative example 1
本对比例公开了一种含镁废液的处理方法，本对比例和实施例1的区别在于，本对比例中的步骤S1中的搅拌反应温度为85℃，其余条件和实施例1相同。This comparative example discloses a method for treating magnesium-containing waste liquid. The difference between this comparative example and Example 1 is that the stirring reaction temperature in step S1 in this comparative example is 85°C, and the other conditions are the same as in Example 1.
对比例2Comparative example 2
本对比例公开了一种含镁废液的处理方法，本对比例和实施例1的区别在于，本对比例 中的步骤S1中的搅拌反应温度为90℃，其余条件和实施例1相同。This comparative example discloses a method for treating magnesium-containing waste liquid. The difference between this comparative example and Example 1 is that this comparative example The stirring reaction temperature in step S1 is 90°C, and the other conditions are the same as in Example 1.
测试例1Test example 1
本测试例对实施例1-3步骤S1中的滤液进行测试，测试结果如表1所示。In this test example, the filtrate in step S1 of Example 1-3 was tested, and the test results are shown in Table 1.
表1.沉镁滤液检测结果
Table 1. Test results of magnesium sedimentation filtrate
测试例2Test example 2
本测试例对实施例1和对比例1-2中的步骤S1中的沉镁滤渣进行测试，测试结果如表2所示。This test example tests the magnesium sedimentation filter residue in step S1 in Example 1 and Comparative Examples 1-2. The test results are shown in Table 2.
表2.沉镁滤渣检测结果
Table 2. Test results of magnesium sedimentation filter residue
表1中实施例2按投料比1:1加入氢氧化钙浆料，因反应比例不能达到100％且过程会有微量损耗，进入含镁废液中的氢氧根不能达到完全沉淀镁的浓度，故滤液中镁的浓度较其他两组实施例的偏高。In Example 2 in Table 1, calcium hydroxide slurry is added at a feeding ratio of 1:1. Since the reaction ratio cannot reach 100% and there will be trace losses during the process, the hydroxide radicals entering the magnesium-containing waste liquid cannot reach the concentration required to completely precipitate magnesium. , so the concentration of magnesium in the filtrate is higher than that of the other two groups of examples.
表2中，对比例1及对比例2中反应温度分别为85℃，90℃，滤渣产物主要为二水硫酸钙，其结晶水及表面水均高于对实施例1所得滤渣，同时造成表面夹带杂质含量高，钠含量在1.5％以上；实施例1反应温度为95℃，滤渣产物主要为半水石膏，其结晶水及表面水含量均低于对比例1及对比例2，同时钠含量仅为0.1％，也远低于对比例1及对比例2。In Table 2, the reaction temperatures in Comparative Example 1 and Comparative Example 2 are 85°C and 90°C respectively. The filter residue product is mainly calcium sulfate dihydrate, and its crystal water and surface water are both higher than those of the filter residue obtained in Example 1. At the same time, the surface The content of entrained impurities is high, and the sodium content is more than 1.5%; the reaction temperature of Example 1 is 95°C, the filter residue product is mainly hemihydrate gypsum, and its crystal water and surface water content are both lower than Comparative Example 1 and Comparative Example 2. At the same time, the sodium content It is only 0.1%, which is also much lower than Comparative Example 1 and Comparative Example 2.
测试例3Test example 3
本测试例对实施例1-3步骤S2中的一次碳化滤液进行测试，测试结果如表3所示。 This test example tests the primary carbonization filtrate in step S2 of Example 1-3, and the test results are shown in Table 3.
表3.一次碳化滤液检测结果
Table 3. Test results of primary carbonization filtrate
测试例4Test example 4
本测试例对实施例1-3步骤S3中的二次碳化滤液进行测试，测试结果如表4所示。This test example tests the secondary carbonization filtrate in step S3 of Example 1-3. The test results are shown in Table 4.
表4.二次碳化滤液检测结果
Table 4. Secondary carbonization filtrate test results
滤饼按照不同固液比进行打浆碳化，参与反应的镁含量基本相同，固液比越低，碳化后滤液中镁浓度越高，实施例3中固液比按10％进行碳化，滤液中镁回收率最高，其工艺是实施例中回收效益相比最佳的。The filter cake is beaten and carbonized according to different solid-liquid ratios. The magnesium content involved in the reaction is basically the same. The lower the solid-liquid ratio, the higher the magnesium concentration in the filtrate after carbonization. In Example 3, the solid-liquid ratio is carbonized at 10%, and the magnesium in the filtrate is The recovery rate is the highest, and its process is the best in terms of recovery efficiency among the examples.
测试例5Test example 5
本测试例对实施例1-3步骤S3中的一次碳化滤液进行测试，测试结果如表5所示。This test example tests the primary carbonization filtrate in step S3 of Example 1-3. The test results are shown in Table 5.
表5.二水硫酸钙结果
Table 5. Calcium sulfate dihydrate results
本发明得到的二水硫酸钙，表面水含水率低，在7％以下，常规二水硫酸钙含水率均在20％以上，因此本发明的二水硫酸钙表面夹带的附着水低，进而整个产品的含水率下降，减少杂质的夹带，进而减少产品洗涤水用量及提高产品品质；同时还能减少后续生成物的烘干成本。The surface water content of the calcium sulfate dihydrate obtained by the present invention is low, below 7%. The moisture content of conventional calcium sulfate dihydrate is above 20%. Therefore, the attached water entrained on the surface of the calcium sulfate dihydrate of the present invention is low, and the entire surface of the calcium sulfate dihydrate has a low moisture content. The moisture content of the product decreases, reducing the entrainment of impurities, thereby reducing the amount of product washing water and improving product quality; it can also reduce the cost of drying subsequent products.
测试例6Test example 6
本测试例对实施例1-3步骤S2中得到的氧化钙进行测试，测试结果如表6所示。 In this test example, the calcium oxide obtained in step S2 of Example 1-3 was tested. The test results are shown in Table 6.
表6.氧化钙检测结果
Table 6. Calcium oxide test results
以上氧化钙为硫酸钙热解还原所得，适用于HG/T 4205-2011中I类化工合成用工业氧化钙标准，氧化钙含量≥92％，氧化镁含量≤1.5％，可作为沉镁剂投加至含镁废液中重复利用。The above calcium oxide is obtained by the pyrolysis reduction of calcium sulfate. It is suitable for industrial calcium oxide standards for Class I chemical synthesis in HG/T 4205-2011. The calcium oxide content is ≥92% and the magnesium oxide content is ≤1.5%. It can be used as a magnesium precipitating agent. Add it to magnesium-containing waste liquid for reuse.
上面结合附图对本发明实施例作了详细说明，但本发明不限于上述实施例，在所属技术领域普通技术人员所具备的知识范围内，还可以在不脱离本发明宗旨的前提下作出各种变化。 The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various modifications can be made without departing from the purpose of the present invention. Variety.

Claims (10)

  1. 一种含镁废液的处理方法，其特征在于，包括如下步骤：A method for treating magnesium-containing waste liquid, characterized in that it includes the following steps:
    S1：将沉镁剂和含镁废水混合，固液分离，收集固相渣；所述混合的温度为95-100℃；所述含镁废水中含有Mg2+和SO4 2-；S1: Mix the magnesium precipitation agent and magnesium-containing wastewater, separate the solid and liquid, and collect the solid phase slag; the mixing temperature is 95-100°C; the magnesium-containing wastewater contains Mg 2+ and SO 4 2- ;
    S2：将步骤S1所得固相渣进行打浆、一次碳化，对碳化产物进行固液分离，收集液相组分；S2: Beat the solid phase residue obtained in step S1 and carbonize it once, perform solid-liquid separation on the carbonized product, and collect the liquid phase components;
    S3：将步骤S2所得液相组分进行热解，并对热解产物进行固液分离，收集固相产物；S3: Pyrolyze the liquid phase components obtained in step S2, conduct solid-liquid separation of the pyrolysis products, and collect the solid phase products;
    S4：将步骤S3所得固相产物进行二次碳化，收集碳化产物的液相组分，制得碳酸氢镁精制液；S4: Carry out secondary carbonization of the solid phase product obtained in step S3, collect the liquid phase components of the carbonized product, and prepare a refined magnesium bicarbonate solution;
    所述沉镁剂包括氧化钙和氢氧化钙中的至少一种；The magnesium precipitating agent includes at least one of calcium oxide and calcium hydroxide;
    所述一次碳化和二次碳化均为反应物和二氧化碳接触。The primary carbonization and secondary carbonization are both the contact between reactants and carbon dioxide.
  2. 根据权利要求1所述的含镁废液的处理方法，其特征在于，所述含镁废水中的Mg2+和所述沉镁剂的摩尔比为1：(1.05-1.1)。The method for treating magnesium-containing waste liquid according to claim 1, characterized in that the molar ratio of Mg 2+ in the magnesium-containing wastewater and the magnesium precipitation agent is 1: (1.05-1.1).
  3. 根据权利要求1所述的含镁废液的处理方法，其特征在于，步骤S2中，所述打浆后的浆料的固含量为10％-20％。The method for treating magnesium-containing waste liquid according to claim 1, characterized in that in step S2, the solid content of the beaten slurry is 10%-20%.
  4. 根据权利要求1所述的含镁废液的处理方法，其特征在于，所述一次碳化后的pH值为7.0-7.5。The method for treating magnesium-containing waste liquid according to claim 1, characterized in that the pH value after primary carbonization is 7.0-7.5.
  5. 根据权利要求1所述的含镁废液的处理方法，其特征在于，所述二次碳化的终止条件为碳化液中的Mg2+的浓度变化率≤0.01g/L。The method of treating magnesium-containing waste liquid according to claim 1, characterized in that the termination condition of the secondary carbonization is that the concentration change rate of Mg 2+ in the carbonized liquid is ≤0.01g/L.
  6. 根据权利要求1所述的含镁废液的处理方法，其特征在于，步骤S3中，所述热解的温度为60-65℃。The method for treating magnesium-containing waste liquid according to claim 1, characterized in that in step S3, the pyrolysis temperature is 60-65°C.
  7. 根据权利要求1所述的含镁废液的处理方法，其特征在于，步骤S2中，还包括对所述固液分离得到的滤渣热解还原为所述沉镁剂。The method for treating magnesium-containing waste liquid according to claim 1, characterized in that step S2 further includes pyrolytic reduction of the filter residue obtained by solid-liquid separation into the magnesium precipitation agent.
  8. 根据权利要求7所述的含镁废液的处理方法，其特征在于，所述滤渣包括硫酸钙；优选地，所述热解还原使用的还原剂包括焦碳。The method for treating magnesium-containing waste liquid according to claim 7, wherein the filter residue includes calcium sulfate; preferably, the reducing agent used in the pyrolysis reduction includes coke.
  9. 根据权利要求8所述的含镁废液的处理方法，其特征在于，按重量比计，所述热解还原的原料配比为，焦炭：硫酸钙＝(0.15-0.2)：1。The method for treating magnesium-containing waste liquid according to claim 8, characterized in that, in terms of weight ratio, the raw material ratio of the pyrolysis reduction is: coke: calcium sulfate = (0.15-0.2): 1.
  10. 根据权利要求8所述的含镁废液的处理方法，其特征在于，所述热解还原的还原剂包括焦碳；优选地，所述热解还原的温度为1000-1300℃。 The method for treating magnesium-containing waste liquid according to claim 8, wherein the reducing agent for pyrolysis reduction includes coke; preferably, the temperature of the pyrolysis reduction is 1000-1300°C.
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101104522A (en) * 2007-06-05 2008-01-16 昆明贵金属研究所 Method for preparing active magnesium chloride by using magnesium sulfate waste liquid
CN101519219A (en) * 2008-02-26 2009-09-02 中国恩菲工程技术有限公司 Manufacturing process for light magnesium carbonate
CN101760641A (en) * 2008-12-24 2010-06-30 中国恩菲工程技术有限公司 Technology for recovering magnesium from magnesium sulfate solution
US20160200587A1 (en) * 2015-01-08 2016-07-14 Industry Foundation Of Chonnam National University Method for manufacturing hydrated magnesium carbonate
CN107098366A (en) * 2017-04-25 2017-08-29 中国恩菲工程技术有限公司 The method for handling magnesium-containing waste solution
CN115385366A (en) * 2022-09-01 2022-11-25 广东邦普循环科技有限公司 Treatment method of magnesium-containing waste liquid

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101760646A (en) * 2008-12-24 2010-06-30 中国恩菲工程技术有限公司 Leaching method of magnesium-containing ore
CN106277417A (en) * 2015-05-26 2017-01-04 有研稀土新材料股份有限公司 The method that smelting waste water comprehensive containing magnesium reclaims

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101104522A (en) * 2007-06-05 2008-01-16 昆明贵金属研究所 Method for preparing active magnesium chloride by using magnesium sulfate waste liquid
CN101519219A (en) * 2008-02-26 2009-09-02 中国恩菲工程技术有限公司 Manufacturing process for light magnesium carbonate
CN101760641A (en) * 2008-12-24 2010-06-30 中国恩菲工程技术有限公司 Technology for recovering magnesium from magnesium sulfate solution
US20160200587A1 (en) * 2015-01-08 2016-07-14 Industry Foundation Of Chonnam National University Method for manufacturing hydrated magnesium carbonate
CN107098366A (en) * 2017-04-25 2017-08-29 中国恩菲工程技术有限公司 The method for handling magnesium-containing waste solution
CN115385366A (en) * 2022-09-01 2022-11-25 广东邦普循环科技有限公司 Treatment method of magnesium-containing waste liquid

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
LINCHENG LIU, ZUO HAIBIN; XU ZHIQIANG: "Effect of powdered carbon on the reductive decomposition of gypsum", JIANGXI METALLURGY, 北京科技大学钢铁冶金新技术国家重点实验室,北京100083, vol. 41, no. 3, 30 June 2021 (2021-06-30), pages 1 - 10, XP093145517, ISSN: 1006-2777, DOI: 10.19864/j.cnki.jxye.2021.03.001 *
RONGGUANG ZHENG, YAN SU: "Study of Distracting High Purity Magnaria By Carlionation Twice", JOURNAL OF EAST CHINA GEOLOGICAL INSTITUTE, vol. 20, no. 2, 30 June 1997 (1997-06-30), pages 173 - 177, XP093145515 *
ZHIQIANG WANG, LIU JIAXIANG; RAO FAMING: "Preparation of High Purity Basic Magnesium Carbonate with Light-burned Dolomite by Twice-Carbonation Method", JOURNAL OF THE CHINESE CERAMIC SOCIETY, vol. 41, no. 10, 24 September 2013 (2013-09-24), pages 1437 - 1441, XP093145520, DOI: 10.7521/j.issn.0454-5648.2013.10.19 *

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