WO2023016056A1 - Method for recovering magnesium oxide from ferronickel slag - Google Patents

Method for recovering magnesium oxide from ferronickel slag Download PDF

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WO2023016056A1
WO2023016056A1 PCT/CN2022/095677 CN2022095677W WO2023016056A1 WO 2023016056 A1 WO2023016056 A1 WO 2023016056A1 CN 2022095677 W CN2022095677 W CN 2022095677W WO 2023016056 A1 WO2023016056 A1 WO 2023016056A1
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magnesium chloride
ferronickel slag
magnesium
solution
crystallization
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PCT/CN2022/095677
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French (fr)
Chinese (zh)
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余海军
钟应声
谢英豪
李爱霞
张学梅
李长东
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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
湖南邦普汽车循环有限公司
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Publication of WO2023016056A1 publication Critical patent/WO2023016056A1/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
    • C01F5/02—Magnesia
    • C01F5/06—Magnesia by thermal decomposition of magnesium compounds
    • 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
    • C01F5/26—Magnesium halides
    • C01F5/30—Chlorides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
    • C22B26/20—Obtaining alkaline earth metals or magnesium
    • C22B26/22—Obtaining magnesium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/006—Wet processes
    • C22B7/007—Wet processes by acid leaching
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/04—Working-up slag
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the invention belongs to the technical field of ferronickel recovery, and in particular relates to a method for recovering magnesium oxide from ferronickel slag.
  • Rotary kiln-electric furnace melting (RKEF) smelting technology has become the mainstream technology for refining nickel from laterite nickel ore due to its ability to simultaneously process different grades of laterite nickel ore, high ferronickel recovery, and high-quality ferronickel production.
  • Nickel accounts for more than 65% of my country's nickel output.
  • the main steps of this technology are: drying and crushing of laterite nickel ore raw materials, roasting with coal powder, smelting and refining in high-temperature furnace.
  • a large amount of ferronickel slag will be discharged.
  • the discharge of ferronickel slag in my country is increasing by 30 million tons every year, and the amount of slag produced accounts for more than 60% of the world's total.
  • ferronickel slag The comprehensive utilization rate of ferronickel slag is low, especially the industrial application of recovering valuable metals from ferronickel slag is almost blank. If these ferronickel slags are directly landfilled or dumped, the environment will be seriously damaged, and reasonable and effective disposal of these slags can not only reduce the harm to the environment and human health, but also obtain considerable benefits from it.
  • ferronickel slag produced by rotary kiln-electric furnace melting (RKEF) technology
  • silicon dioxide and metal oxides account for the most, of which silicon dioxide accounts for 40-60%, magnesium oxide accounts for 20-40%, and iron oxide The proportion is 5-8%, alumina is 2-5%, and calcium oxide is 1-5%.
  • ferronickel slag has the characteristics of high magnesium and low calcium aluminum iron, so it will also extract magnesium, ferronickel from ferronickel slag. In the process of iron and other metals, more impurities remain in the metal salts, resulting in lower product quality.
  • the present invention provides a method for recovering high-purity magnesium oxide from ferronickel slag.
  • the present invention aims to solve at least one of the technical problems in the above-mentioned prior art. For this reason, the present invention proposes a kind of method that reclaims magnesia in ferronickel slag, and the present invention utilizes acid atmospheric pressure to leach ferronickel slag, adds alkali again to adjust pH, carries out precipitation reaction, removes iron and aluminum, and is equipped with crystal seed. The first crystallization is carried out under the premise, and then the secondary crystallization is carried out to obtain high-purity magnesium oxide and increase the recovery rate of magnesium.
  • the present invention adopts the following technical solutions:
  • a method for reclaiming magnesium oxide in ferronickel slag comprising the following steps:
  • the magnesium chloride crystal is subjected to secondary crystallization, and the obtained crystal is heated and decomposed to obtain magnesium oxide.
  • crushing and drying ferronickel are also included; the drying temperature is 300-650° C., and the drying time is 1-2 hours.
  • the liquid-solid ratio of the ferronickel slag and acid is 10: (40-80) ml/g.
  • the purity of the hydrochloric acid is industrial grade or above.
  • the temperature of the heating reaction is 150-240° C., and the heating reaction time is 30-40 minutes.
  • step (1) before the solid-liquid separation, water washing is also included, and the temperature of the water washing is 50-95° C., and the water washing is 1-2 times.
  • the volume ratio of ferronickel slag slurry to hot water in the water washing process is 10:(30-60).
  • the salt in the hydrochloric acid washing solution is at least one of magnesium chloride, ferric chloride, aluminum chloride or calcium chloride.
  • the concentration is: evaporate part of the water until the water content of the acid washing solution is reduced by 200-400ml/L, and the evaporation temperature is 70-90°C.
  • the pH adjustment is to adjust the pH of the acid washing solution to 3.0-5.5.
  • the lye used for adding alkali to adjust pH is ammonia water.
  • the seed crystal is magnesium chloride.
  • the dosage of the seed crystal is 0.2-5 g/10L.
  • step (3) after the primary crystallization, the acidity of the solution is detected to be 20%-37%, and suction filtration is performed to obtain magnesium chloride crystals.
  • step (3) it also includes acid washing the magnesium chloride crystals, and suction filtering to obtain magnesium chloride.
  • the amount of acid used in the pickling and the liquid-solid ratio of the magnesium chloride crystals are 1-1.5ml/g.
  • the specific step of the secondary crystallization is to dissolve the magnesium chloride crystals with water to obtain a magnesium chloride solution, then add them to the seed crystals for stirring, and introduce gas for secondary crystallization to obtain magnesium chloride crystals.
  • the seed crystal dosage of the secondary crystallization is 0.2-5 g/10L.
  • step (4) acid washing the obtained crystals is also included before the thermal decomposition.
  • the pickling may be pickling with concentrated hydrochloric acid.
  • the acidity of the solution is 20%-37%.
  • the temperature of the thermal decomposition is 550-700° C., and the time is 150-300 min.
  • the present invention utilizes acid atmospheric pressure to leach ferronickel slag (after measurement, silicon dioxide and magnesium oxide account for the most in the ferronickel slag utilized, wherein silicon dioxide accounts for about 48%, and magnesium oxide is as high as 28.4%) , add alkali to adjust the pH, carry out precipitation reaction, remove iron and aluminum, perform primary crystallization in a crystallization device equipped with crystal seeds, and then perform secondary crystallization to obtain 97.1% to 98.3% high-purity magnesium oxide.
  • the recovery rate of magnesium is high, has reached 89.4 ⁇ 92.0%, therefore utilize recovery process of the present invention, can reclaim 15.2t ⁇ 15.7t magnesium in 100t ferronickel slag, according to current price of magnesium at 19,000 yuan/ t calculation, the production value of 100t of aluminum slag to extract magnesium is 289,000 to 298,000 yuan, and the economic benefits are considerable, so the potential value of recycling is huge.
  • the present invention utilizes the gaseous crystallization method to enable magnesium chloride to be crystallized in a relatively active state, and the yield of crystallized magnesium chloride is higher.
  • the introduction of hydrogen chloride into the crystallization device can make the acid washing solution crystallize at >40°C (crystallization at high temperature, the waste liquid recovery should be in a high-energy state, and the energy consumed by heating and recovering acid is less) to crystallize MgCl 2 6H 2 O, no need
  • the temperature is lowered to crystallize and the crystallization temperature is higher than normal temperature. Therefore, the filtrate after crystallization can be directly sent to the evaporation device for separation, and the hydrogen chloride is recovered by evaporation, which reduces the energy consumption required for heating, greatly reduces the energy consumption of regeneration, and indirectly reduces the cost.
  • the present invention utilizes gaseous crystallization and concentrated hydrochloric acid pickling to purify magnesium chloride.
  • hydrogen chloride gas is introduced into the acid washing liquid, the precipitation rate of MgCl 2 will increase according to the high concentration of Mg 2+ , and the precipitation rate of other element ions will also increase accordingly.
  • the crystallization sequence of the substance (AlCl 3 >MgCl 2 >FeCl 3 ) makes MgCl 2 preferentially crystallize out as MgCl 2 , and controls the acidity of the crystallization system. Most of the impurity ions still remain in the remaining acid solution after crystallization. Wash pure magnesium chloride crystals to achieve the purpose of secondary impurity removal.
  • Fig. 1 is a flowchart of Embodiment 1 of the present invention.
  • Fig. 2 is the SEM figure of the nickel-iron slag powder of embodiment 1 of the present invention.
  • Figure 3 is a SEM image of magnesium oxide in Example 1 of the present invention.
  • Magnesium chloride crystals are dissolved with pure water to obtain 9.0L magnesium chloride solution, which is placed in a crystallization device.
  • the crystallization device adds 1.8g of magnesium chloride seed crystals in advance, and the stirring speed is stirred at 120rmp, and hydrogen chloride gas is fed into the magnesium chloride solution to crystallize
  • One end of the device collects the hydrogen chloride discharged from the solution until the acidity of the magnesium chloride solution is 25.6%, stops feeding the hydrogen chloride, takes out the acid solution, and obtains 1.79 kg of secondary magnesium chloride crystals, pickling with 1.9 L of industrial grade hydrochloric acid and the magnesium chloride crystals, and suctioning the acid
  • the solution is acid-washed magnesium chloride, and the acid-washed magnesium chloride is heated and decomposed in a decomposition furnace at 620°C for 185 minutes to obtain high-purity magnesium oxide.
  • Fig. 1 is the flow chart of embodiment 1, and ferronickel slag is crushed and ground to obtain ferronickel slag powder, and ferronickel slag powder is heated in the kiln under ventilation. After heating, transfer it to an airtight container to react with hydrochloric acid, cool to obtain ferronickel slag slurry, wash the ferronickel slag slurry with hot water and then suction filter to obtain hydrochloric acid washing solution, then evaporate to remove most of hydrogen chloride, and add ammonia to remove the formed
  • the iron-removing aluminum solution is obtained by depositing the iron-removing aluminum solution, and the iron-removing aluminum solution is sent to the container, and magnesium chloride seed crystals are added and chlorine hydrogenation is introduced to carry out crystallization, and the magnesium chloride crystals are pickled with concentrated hydrochloric acid, and the remaining acid solution after crystallization and The remaining acid liquid is sent to the evaporator to evaporate and recover hydrogen chloride.
  • the obtained acid-washed magnesium chloride is sent to the decomposition
  • Fig. 2 is the SEM picture of the ferronickel slag powder of embodiment 1, can find out from Fig. 2 that the fine powder of ferronickel slag powder of embodiment 1 is mixed with some massive, elongated flaky particles.
  • Figure 3 is a SEM image of the magnesium oxide prepared in Example 1. It can be seen from Figure 3 that the granular magnesium oxide prepared in Example 1 is ⁇ 10 ⁇ m, and the particle distribution is uniform.
  • Magnesium chloride crystals are dissolved with pure water to obtain 8.7L magnesium chloride solution, which is placed in a crystallization device.
  • the crystallization device adds 2.3 g of magnesium chloride seed crystals in advance, and the stirring speed is stirred at 120 rpm, and hydrogen chloride gas is fed into the magnesium chloride solution to crystallize
  • One end of the device collects and discharges the hydrogen chloride of the secondary solution, until the acidity of the magnesium chloride solution is 27.4%, stops feeding the hydrogen chloride, takes out the acid solution, and obtains 1.64kg of secondary magnesium chloride crystals, pickling with 1.7L industrial grade hydrochloric acid and the magnesium chloride crystals, pumping Filtrate the acid solution to obtain acid-washed magnesium chloride, which is heated and decomposed in a decomposition furnace at 620°C for 185 minutes to obtain high-purity magnesium oxide.
  • the iron-removing aluminum hydrochloric acid washing solution is sent to the crystallization device, and the crystallization device adds 3.0 g of magnesium chloride seeds in advance, stirs at a stirring rate of 120rmp, feeds hydrogen chloride gas into the acid washing solution, and one end of the crystallization device collects and discharges the solution Hydrogen chloride, when the acidity of magnesium chloride solution is 29.3%, stop feeding hydrogen chloride, take out acid solution, obtain 2.33kg primary magnesium chloride crystal;
  • Magnesium chloride crystals are dissolved with pure water to obtain 9.8L magnesium chloride solution, which is placed in a crystallization device.
  • the crystallization device adds 3.1 g of magnesium chloride seed crystals in advance, and the stirring speed is stirred at 120 rpm, and hydrogen chloride gas is fed into the magnesium chloride solution to crystallize
  • One end of the device collects the hydrogen chloride discharged from the solution until the acidity of the magnesium chloride solution is 28.3%, stops feeding the hydrogen chloride, and removes the acid solution to obtain 2.27 kg of secondary magnesium chloride crystals, pickling with 2.5 L of industrial grade hydrochloric acid and magnesium chloride crystals, and suctioning the acid
  • the solution is acid-washed magnesium chloride, and the acid-washed magnesium chloride is heated and decomposed in a decomposition furnace at 620°C for 190 minutes to obtain high-purity magnesium oxide.
  • the method for recovering magnesium oxide from ferronickel slag of the present embodiment comprises the following steps.
  • Magnesium chloride crystal is dissolved with pure water to obtain 8.7L magnesium chloride solution, is placed in the crystallization device, the magnesium chloride seed crystal of 3.6g is added in advance in the crystallization device, stirring speed is stirred under 120rmp, feeds hydrogen chloride gas and enters in the magnesium chloride solution, crystallization One end of the device collects the hydrogen chloride discharged from the solution until the acidity of the magnesium chloride solution is 29.73%, stops feeding the hydrogen chloride, and removes the acid solution to obtain 2.12 kg of secondary magnesium chloride crystals, pickling with 1.8 L of industrial grade hydrochloric acid and magnesium chloride crystals, and suctioning the acid The solution is acid-washed magnesium chloride, which is heated and decomposed in a decomposition furnace at 620°C for 197 minutes to obtain high-purity magnesium oxide.
  • the quality (kg) of magnesium in the primary magnesium chloride crystal the primary magnesium chloride crystal total mass * the concentration of magnesium in the magnesium chloride crystal acid solution to be measured * the dilution factor/the magnesium chloride crystal quality to be measured;
  • the quality (kg) of magnesium in the secondary magnesium chloride crystal the secondary magnesium chloride crystal total mass * the concentration of magnesium in the magnesium chloride crystal acid solution to be measured * the dilution factor/magnesium chloride crystal quality to be measured;
  • Magnesium oxide purity after thermal decomposition (%) magnesium oxide quality after thermal decomposition of secondary magnesium chloride crystals/total mass after thermal decomposition of secondary magnesium chloride crystals ⁇ 100%;
  • Magnesium recovery rate (%) mass of magnesium oxide after thermal decomposition of secondary magnesium chloride crystal ⁇ magnesia purity ⁇ 0.6/mass of magnesium in ferronickel slag ⁇ 100%.

Abstract

The present invention belongs to the technical field of ferronickel recovery, and discloses a method for recovering magnesium oxide from ferronickel slag, the method comprising the steps of: crushing and drying ferronickel slag, adding acid, mixing, heating and reacting same, subjecting same to solid-liquid separation, and taking the liquid phase to obtain an acid water-washed solution; concentrating the acid water-washed solution, adding an alkali to adjust the pH, subjecting same to a precipitation reaction, and separating out the liquid phase to obtain an iron-aluminum-removed hydrochloric acid water-washed solution; adding the iron-aluminum-removed hydrochloric acid water-washed solution to a seed crystal and stirring same, introducing hydrogen chloride, and subjecting same to primary crystallization and suction filtering same to obtain magnesium chloride crystals; and subjecting same to secondary crystallization, and then heat-decomposing same to obtain magnesium oxide. According to the present invention, the ferronickel slag is leached by means of acid at a normal pressure, then has an alkali added thereto to adjust the pH, is subjected to a precipitation reaction for removing iron and aluminum, and is subjected to primary crystallization, on the premise of being loaded with seed crystals, and then secondary crystallization, so as to obtain the high-purity magnesium oxide while increasing the recovery rate of magnesium.

Description

一种镍铁渣中回收氧化镁的方法A kind of method that reclaims magnesium oxide in ferronickel slag 技术领域technical field
本发明属于镍铁回收技术领域，具体涉及一种镍铁渣中回收氧化镁的方法。The invention belongs to the technical field of ferronickel recovery, and in particular relates to a method for recovering magnesium oxide from ferronickel slag.
背景技术Background technique
转窑-电炉熔(RKEF)炼技术因以能同时处理不同品位的红土镍矿、镍铁回收高、产镍铁品质高等特点成为当前红土镍矿提炼金属镍的主流技术，该技术生产的金属镍占我国镍产量65％以上。该技术主要步骤为：红土镍矿原料干燥破碎，加煤粉焙烧，高温炉熔炼、精炼。然而该技术在冶炼过程中，会排出大量镍铁渣，我国镍铁渣每年以0.3亿吨的排放量增长，产渣的量占比达全球的60％以上。镍铁渣的综合利用率低，特别是从镍铁渣中回收有价金属的工业化应用，几乎为空白。这些镍铁渣如果直接填埋、堆弃处理，会严重破坏环境，而合理有效的处理这些炉渣，不仅可以减少对环境和人类健康的危害，还可以从中获得可观的收益。Rotary kiln-electric furnace melting (RKEF) smelting technology has become the mainstream technology for refining nickel from laterite nickel ore due to its ability to simultaneously process different grades of laterite nickel ore, high ferronickel recovery, and high-quality ferronickel production. Nickel accounts for more than 65% of my country's nickel output. The main steps of this technology are: drying and crushing of laterite nickel ore raw materials, roasting with coal powder, smelting and refining in high-temperature furnace. However, during the smelting process of this technology, a large amount of ferronickel slag will be discharged. The discharge of ferronickel slag in my country is increasing by 30 million tons every year, and the amount of slag produced accounts for more than 60% of the world's total. The comprehensive utilization rate of ferronickel slag is low, especially the industrial application of recovering valuable metals from ferronickel slag is almost blank. If these ferronickel slags are directly landfilled or dumped, the environment will be seriously damaged, and reasonable and effective disposal of these slags can not only reduce the harm to the environment and human health, but also obtain considerable benefits from it.
转窑-电炉熔(RKEF)技术产的镍铁渣以二氧化硅和金属氧化物占比最多，其中二氧化硅占比在40～60％，氧化镁占比在20～40％，氧化铁占比在5～8％，氧化铝在2～5％，氧化钙在1～5％，可见，镍铁渣具有高镁、低钙铝铁的特点，因此也将在镍铁渣提炼镁、铁等金属过程中，金属盐中残留较多的杂质，导致产品品质质量降低。当前，对于镍铁渣中回收镁的工业生产方法也缺少相应的技术参考。基于所述情况，本发明提供一种镍铁渣中回收高纯度氧化镁的方法。In the ferronickel slag produced by rotary kiln-electric furnace melting (RKEF) technology, silicon dioxide and metal oxides account for the most, of which silicon dioxide accounts for 40-60%, magnesium oxide accounts for 20-40%, and iron oxide The proportion is 5-8%, alumina is 2-5%, and calcium oxide is 1-5%. It can be seen that ferronickel slag has the characteristics of high magnesium and low calcium aluminum iron, so it will also extract magnesium, ferronickel from ferronickel slag. In the process of iron and other metals, more impurities remain in the metal salts, resulting in lower product quality. At present, there is also a lack of corresponding technical references for the industrial production method of recovering magnesium from ferronickel slag. Based on the above situation, the present invention provides a method for recovering high-purity magnesium oxide from ferronickel slag.
发明内容Contents of the invention
本发明旨在至少解决上述现有技术中存在的技术问题之一。为此，本发明提出一种镍铁渣中回收氧化镁的方法，本发明利用酸常压浸出镍铁渣，再加碱调pH，进行沉淀反应，除掉铁铝，再在装有晶种的前提下进行一次结晶，之后再进行二次结晶，得到高纯度氧化镁的同时增加镁的回收率。The present invention aims to solve at least one of the technical problems in the above-mentioned prior art. For this reason, the present invention proposes a kind of method that reclaims magnesia in ferronickel slag, and the present invention utilizes acid atmospheric pressure to leach ferronickel slag, adds alkali again to adjust pH, carries out precipitation reaction, removes iron and aluminum, and is equipped with crystal seed The first crystallization is carried out under the premise, and then the secondary crystallization is carried out to obtain high-purity magnesium oxide and increase the recovery rate of magnesium.
为实现上述目的，本发明采用以下技术方案：To achieve the above object, the present invention adopts the following technical solutions:
一种镍铁渣中回收氧化镁的方法，包括以下步骤：A method for reclaiming magnesium oxide in ferronickel slag, comprising the following steps:
(1)向镍铁渣中加入盐酸混合，加热反应，固液分离，取液相，即得酸水洗液；(1) adding hydrochloric acid to ferronickel slag to mix, heating for reaction, separating solid and liquid, taking the liquid phase to obtain acid washing solution;
(2)将所述酸水洗液进行浓缩，加碱调pH，进行沉淀反应，分离出液相，得到除铁铝盐酸水洗液；(2) Concentrating the acid washing liquid, adding alkali to adjust the pH, carrying out precipitation reaction, separating the liquid phase, and obtaining the iron-removing aluminum hydrochloric acid washing liquid;
(3)将所述除铁铝盐酸水洗液加入晶种中搅拌，通入氯化氢，进行一次结晶，固液分离，即得氯化镁晶体；(3) Add the washing solution of iron-removing aluminum hydrochloric acid into the seed crystal and stir, feed hydrogen chloride, carry out primary crystallization, and separate solid and liquid to obtain magnesium chloride crystals;
(4)将所述氯化镁晶体进行二次结晶，所得晶体加热分解，得到氧化镁。(4) The magnesium chloride crystal is subjected to secondary crystallization, and the obtained crystal is heated and decomposed to obtain magnesium oxide.
优选地，步骤(1)中所述加入酸混合前还包括将镍铁粉碎、干燥；所述干燥的温度为300～650℃，干燥的时间为1～2h。Preferably, before adding acid and mixing in step (1), crushing and drying ferronickel are also included; the drying temperature is 300-650° C., and the drying time is 1-2 hours.
优选地，步骤(1)中，所述镍铁渣和酸的液固比为10：(40～80)ml/g。Preferably, in step (1), the liquid-solid ratio of the ferronickel slag and acid is 10: (40-80) ml/g.
优选地，步骤(1)中，所述盐酸的纯度为工业级或以上。Preferably, in step (1), the purity of the hydrochloric acid is industrial grade or above.
优选地，步骤(1)中，所述加热反应的温度为150～240℃，加热反应的时间为30～40min。Preferably, in step (1), the temperature of the heating reaction is 150-240° C., and the heating reaction time is 30-40 minutes.
优选地，步骤(1)中，所述固液分离前还包括进行水洗，所述水洗采用的温度为50～95℃的水，水洗1～2次。Preferably, in step (1), before the solid-liquid separation, water washing is also included, and the temperature of the water washing is 50-95° C., and the water washing is 1-2 times.
优选地，所述水洗过程中镍铁渣浆料和热水的体积比为10：(30～60)。Preferably, the volume ratio of ferronickel slag slurry to hot water in the water washing process is 10:(30-60).
优选地，步骤(1)中，所述盐酸水洗液中的盐为氯化镁、氯化铁、氯化铝或氯化钙中的至少一种。Preferably, in step (1), the salt in the hydrochloric acid washing solution is at least one of magnesium chloride, ferric chloride, aluminum chloride or calcium chloride.
优选地，步骤(2)中，所述浓缩为：蒸发部分水量至酸水洗液水含量减少200～400ml/L，蒸发的温度在70～90℃。Preferably, in step (2), the concentration is: evaporate part of the water until the water content of the acid washing solution is reduced by 200-400ml/L, and the evaporation temperature is 70-90°C.
优选地，步骤(2)中，所述调pH是将酸水洗液的pH调节至3.0～5.5。Preferably, in step (2), the pH adjustment is to adjust the pH of the acid washing solution to 3.0-5.5.
优选地，步骤(2)中，所述加碱调pH使用的碱液为氨水。Preferably, in step (2), the lye used for adding alkali to adjust pH is ammonia water.
酸水洗液加入碱液，调节酸水洗液pH，利用水解沉淀，生成沉淀物，过滤除去沉淀物(铁、铝)。Add lye to the acid washing solution to adjust the pH of the acid washing solution, use hydrolysis and precipitation to generate precipitates, and filter to remove the precipitates (iron, aluminum).
优选地，步骤(3)中，所述晶种为氯化镁。Preferably, in step (3), the seed crystal is magnesium chloride.
优选地，步骤(3)中，所述晶种投加量在0.2～5g/10L。Preferably, in step (3), the dosage of the seed crystal is 0.2-5 g/10L.
优选地，步骤(3)中，所述一次结晶后，检测溶液的酸度为20％～37％，进行抽滤，得到氯化镁晶体。Preferably, in step (3), after the primary crystallization, the acidity of the solution is detected to be 20%-37%, and suction filtration is performed to obtain magnesium chloride crystals.
优选地，步骤(3)中，还包括对所述氯化镁晶体进行酸洗，抽滤，得到氯化镁。Preferably, in step (3), it also includes acid washing the magnesium chloride crystals, and suction filtering to obtain magnesium chloride.
进一步优选地，所述酸洗中酸的用量与氯化镁晶体的液固比为1～1.5ml/g。Further preferably, the amount of acid used in the pickling and the liquid-solid ratio of the magnesium chloride crystals are 1-1.5ml/g.
优选地，步骤(4)中，所述二次结晶的具体步骤为将氯化镁晶体加水溶解得到氯化镁溶液，再加入晶种中搅拌，通入气体，进行二次结晶，得到氯化镁晶体。Preferably, in step (4), the specific step of the secondary crystallization is to dissolve the magnesium chloride crystals with water to obtain a magnesium chloride solution, then add them to the seed crystals for stirring, and introduce gas for secondary crystallization to obtain magnesium chloride crystals.
进一步优选地，所述二次结晶的晶种投加量为0.2～5g/10L。Further preferably, the seed crystal dosage of the secondary crystallization is 0.2-5 g/10L.
优选地，步骤(4)中，所述加热分解前还包括对所得晶体进行酸洗。Preferably, in step (4), acid washing the obtained crystals is also included before the thermal decomposition.
进一步优选地，所述酸洗可以采用浓盐酸酸洗。Further preferably, the pickling may be pickling with concentrated hydrochloric acid.
优选地，所述二次结晶后，溶液的酸度20％～37％。Preferably, after the secondary crystallization, the acidity of the solution is 20%-37%.
优选地，所述加热分解的温度为550～700℃，时间为150～300min。Preferably, the temperature of the thermal decomposition is 550-700° C., and the time is 150-300 min.
相对于现有技术，本发明的有益效果如下：Compared with the prior art, the beneficial effects of the present invention are as follows:
1、本发明利用酸常压浸出镍铁渣(经过测定，利用的镍铁渣中二氧化硅和氧化镁占比最多，其中二氧化硅占比在48％左右，而氧化镁高达28.4％)，再加碱调pH，进行沉淀反应，除掉铁铝，再在装有晶种的结晶装置中进行一次结晶，之后再进行二次结晶，得到97.1％～98.3％高纯度氧化镁。利用上述的回收工艺，镁的回收率高，达到了89.4～92.0％，因此利用本发明的回收工艺，100t镍铁渣中能回收15.2t～15.7t镁，按照目前镁价格在1.9万元/t计算，100t铝渣提炼镁的生产值为28.9万元～29.8万元，经济效益可观，因此回收潜在的价值巨大。1. The present invention utilizes acid atmospheric pressure to leach ferronickel slag (after measurement, silicon dioxide and magnesium oxide account for the most in the ferronickel slag utilized, wherein silicon dioxide accounts for about 48%, and magnesium oxide is as high as 28.4%) , add alkali to adjust the pH, carry out precipitation reaction, remove iron and aluminum, perform primary crystallization in a crystallization device equipped with crystal seeds, and then perform secondary crystallization to obtain 97.1% to 98.3% high-purity magnesium oxide. Utilize above-mentioned recovery process, the recovery rate of magnesium is high, has reached 89.4～92.0%, therefore utilize recovery process of the present invention, can reclaim 15.2t～15.7t magnesium in 100t ferronickel slag, according to current price of magnesium at 19,000 yuan/ t calculation, the production value of 100t of aluminum slag to extract magnesium is 289,000 to 298,000 yuan, and the economic benefits are considerable, so the potential value of recycling is huge.
2、本发明利用气态结晶法使得氯化镁能在较高活跃状态下进行结晶，并且能使结晶析出的氯化镁产率较高。结晶装置中通入氯化氢可以使得酸水洗液在>40℃(高温下结晶，产生的废液回收要高能态下加热回收酸消耗的能量少)下进行结晶得MgCl 2·6H 2O，不需要降温结晶且结晶温度高于常温。因此结晶后的滤液可以直接送至蒸发装置进行分离，蒸发回收氯化氢，减少加热所需能耗，大大降低再生能耗，间接降低成本。 2. The present invention utilizes the gaseous crystallization method to enable magnesium chloride to be crystallized in a relatively active state, and the yield of crystallized magnesium chloride is higher. The introduction of hydrogen chloride into the crystallization device can make the acid washing solution crystallize at >40°C (crystallization at high temperature, the waste liquid recovery should be in a high-energy state, and the energy consumed by heating and recovering acid is less) to crystallize MgCl 2 6H 2 O, no need The temperature is lowered to crystallize and the crystallization temperature is higher than normal temperature. Therefore, the filtrate after crystallization can be directly sent to the evaporation device for separation, and the hydrogen chloride is recovered by evaporation, which reduces the energy consumption required for heating, greatly reduces the energy consumption of regeneration, and indirectly reduces the cost.
3、本发明利用气态结晶法和浓盐酸酸洗能提纯氯化镁。通入氯化氢气体进入酸水洗液时，依据高浓度的Mg 2+，MgCl 2析出率将增大，其他元素离子的析出率也相应增大，但在优先除去Al、Fe的条件下，利用不同物质的结晶顺序(AlCl 3>MgCl 2>FeCl 3)使得MgCl 2优先以MgCl 2结晶出来，控制结晶体系的酸度，大部分杂质离子仍然残留在结晶后剩余的酸液中，同时利用浓酸酸洗纯氯化镁晶体，达到二次除杂的目的。 3. The present invention utilizes gaseous crystallization and concentrated hydrochloric acid pickling to purify magnesium chloride. When hydrogen chloride gas is introduced into the acid washing liquid, the precipitation rate of MgCl 2 will increase according to the high concentration of Mg 2+ , and the precipitation rate of other element ions will also increase accordingly. However, under the condition of preferential removal of Al and Fe, different The crystallization sequence of the substance (AlCl 3 >MgCl 2 >FeCl 3 ) makes MgCl 2 preferentially crystallize out as MgCl 2 , and controls the acidity of the crystallization system. Most of the impurity ions still remain in the remaining acid solution after crystallization. Wash pure magnesium chloride crystals to achieve the purpose of secondary impurity removal.
附图说明Description of drawings
图1为本发明实施例1的流程图。Fig. 1 is a flowchart of Embodiment 1 of the present invention.
图2为本发明实施例1镍铁渣粉的SEM图；Fig. 2 is the SEM figure of the nickel-iron slag powder of embodiment 1 of the present invention;
图3为本发明实施例1氧化镁的SEM图。Figure 3 is a SEM image of magnesium oxide in Example 1 of the present invention.
具体实施方式Detailed ways
以下将结合实施例对本发明的构思及产生的技术效果进行清楚、完整地描述，以充分地理解本发明的目的、特征和效果。显然，所描述的实施例只是本发明的一部分实施例，而不是全部实施例，基于本发明的实施例，本领域的技术人员在不付出创造性劳动的前提下所获得的其他实施例，均属于本发明保护的范围。The conception and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments, so as to fully understand the purpose, features and effects of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts belong to The protection scope of the present invention.
实施例1Example 1
本实施例的镍铁渣中回收氧化镁的方法，包括以下步骤：The method for reclaiming magnesium oxide in the ferronickel slag of the present embodiment may further comprise the steps:
(1)将镍铁渣破碎为镍铁渣碎屑，进行研磨、筛分得1.21kg的镍铁渣粉，将镍铁渣粉在窑炉420℃下干燥，加入5.5L工业级盐酸进行混合，送至密闭容器，在216℃下反应30min，冷却至常温，镍铁渣浆料用76℃的热水水洗2次，抽滤，即得11L的盐酸水洗液；(1) Crushing ferronickel slag into ferronickel slag chips, grinding and sieving to obtain 1.21kg of ferronickel slag powder, drying the ferronickel slag powder in a kiln at 420°C, adding 5.5L industrial grade hydrochloric acid for mixing , sent to a closed container, reacted at 216°C for 30min, cooled to room temperature, washed the ferronickel slag slurry twice with hot water at 76°C, and suction filtered to obtain 11L of hydrochloric acid washing solution;
(2)将盐酸水洗液在80℃下进行蒸发剩余至8.4L，加氨溶液调pH为5.44，沉淀反应，过滤取滤液，得到9.2L的除铁铝盐酸水洗液；(2) Evaporate the hydrochloric acid washing solution at 80° C. to 8.4 L, add ammonia solution to adjust the pH to 5.44, conduct a precipitation reaction, filter the filtrate, and obtain 9.2 L of iron-removing aluminum hydrochloric acid washing solution;
(3)将除铁铝盐酸水洗液送至结晶装置中，结晶装置预先加入1.9g的氯化镁晶种，120rmp搅拌速率下搅拌，通入氯化氢气体进入酸水洗液中，结晶装置一端收集排出溶液的氯化氢，直至氯化镁溶液的酸度为28.7％时，停止通入氯化氢，抽去酸液，即得1.87kg一次氯化镁晶体；(3) Send the iron-removing aluminum hydrochloric acid washing solution to the crystallization device, and the crystallization device adds 1.9g of magnesium chloride seed crystals in advance, stirs at a stirring rate of 120rmp, feeds hydrogen chloride gas into the acid washing solution, and one end of the crystallization device collects and discharges the solution Hydrogen chloride, when the acidity of magnesium chloride solution is 28.7%, stop feeding hydrogen chloride, take out acid solution, obtain 1.87kg primary magnesium chloride crystal;
(4)将氯化镁晶体用纯水溶解得9.0L氯化镁溶液，置于结晶装置中，结晶装置预先加入1.8g的氯化镁晶种，搅拌速率为120rmp下搅拌，通入氯化氢气体进入氯化镁溶液中，结晶装置一端收集排出溶液的氯化氢，直至氯化镁溶液的酸度为25.6％时，停止通入氯化氢，抽去酸液，得到1.79kg二次氯化镁晶体，1.9L工业级盐酸与氯化镁晶体酸洗，抽滤酸液得酸洗氯化镁，酸洗氯化镁在分解炉620℃下加热分解185min，得到高纯度氧化镁。(4) Magnesium chloride crystals are dissolved with pure water to obtain 9.0L magnesium chloride solution, which is placed in a crystallization device. The crystallization device adds 1.8g of magnesium chloride seed crystals in advance, and the stirring speed is stirred at 120rmp, and hydrogen chloride gas is fed into the magnesium chloride solution to crystallize One end of the device collects the hydrogen chloride discharged from the solution until the acidity of the magnesium chloride solution is 25.6%, stops feeding the hydrogen chloride, takes out the acid solution, and obtains 1.79 kg of secondary magnesium chloride crystals, pickling with 1.9 L of industrial grade hydrochloric acid and the magnesium chloride crystals, and suctioning the acid The solution is acid-washed magnesium chloride, and the acid-washed magnesium chloride is heated and decomposed in a decomposition furnace at 620°C for 185 minutes to obtain high-purity magnesium oxide.
图1为实施例1的流程图，将镍铁渣破碎研磨得到镍铁渣粉，通空气下窑炉中加热镍铁渣粉。加热完毕移送至密闭容器中与盐酸反应，冷却得到镍铁渣浆料，镍铁渣浆料用热水水洗再抽滤，得到盐酸水洗液，再蒸发除去大部分氯化氢，加氨后，除去生成的沉淀得除铁铝溶液，除铁铝溶液送至容器中，加氯化镁晶种和通入氯加氢进行结晶，得 氯化镁晶体用浓盐酸进行酸洗，结晶后剩余的酸液和酸洗后剩余的酸液送至蒸发装置中蒸发回收氯化氢。得到的酸洗氯化镁送至分解炉中加热分解，得到高纯度的氧化镁。Fig. 1 is the flow chart of embodiment 1, and ferronickel slag is crushed and ground to obtain ferronickel slag powder, and ferronickel slag powder is heated in the kiln under ventilation. After heating, transfer it to an airtight container to react with hydrochloric acid, cool to obtain ferronickel slag slurry, wash the ferronickel slag slurry with hot water and then suction filter to obtain hydrochloric acid washing solution, then evaporate to remove most of hydrogen chloride, and add ammonia to remove the formed The iron-removing aluminum solution is obtained by depositing the iron-removing aluminum solution, and the iron-removing aluminum solution is sent to the container, and magnesium chloride seed crystals are added and chlorine hydrogenation is introduced to carry out crystallization, and the magnesium chloride crystals are pickled with concentrated hydrochloric acid, and the remaining acid solution after crystallization and The remaining acid liquid is sent to the evaporator to evaporate and recover hydrogen chloride. The obtained acid-washed magnesium chloride is sent to the decomposition furnace to be heated and decomposed to obtain high-purity magnesium oxide.
图2为实施例1镍铁渣粉的SEM图，从图2中可以看出实施例1的镍铁渣粉细粉末夹杂了部分块状、长片状颗粒。Fig. 2 is the SEM picture of the ferronickel slag powder of embodiment 1, can find out from Fig. 2 that the fine powder of ferronickel slag powder of embodiment 1 is mixed with some massive, elongated flaky particles.
图3为实施例1制备的氧化镁的SEM图，从图3中可以看出实施例1制备的颗粒氧化镁<10μm，颗粒分布均匀。Figure 3 is a SEM image of the magnesium oxide prepared in Example 1. It can be seen from Figure 3 that the granular magnesium oxide prepared in Example 1 is <10 μm, and the particle distribution is uniform.
实施例2Example 2
本实施例的镍铁渣中回收氧化镁的方法，包括以下步骤：The method for reclaiming magnesium oxide in the ferronickel slag of the present embodiment may further comprise the steps:
(1)将镍铁渣破碎为镍铁渣碎屑，进行研磨、筛分得1.13kg镍铁渣粉，将镍铁渣粉在420℃干燥、加入5.2L工业级盐酸进行混合，送至密闭容器，在207℃下反应34min，冷却至常温，镍铁渣浆料用76℃的热水水洗2次，抽滤，即得10.3L盐酸水洗液；(1) Crushing the ferronickel slag into ferronickel slag debris, grinding and sieving to obtain 1.13kg of ferronickel slag powder, drying the ferronickel slag powder at 420°C, adding 5.2L industrial grade hydrochloric acid for mixing, and sending it to a closed The container was reacted at 207°C for 34 minutes, cooled to room temperature, the ferronickel slag slurry was washed twice with hot water at 76°C, and suction filtered to obtain 10.3L of hydrochloric acid washing solution;
(2)将盐酸水洗液在80℃下进行蒸发剩余至7.9L，加氨溶液调pH为5.37，沉淀反应，过滤取滤液，得到8.7L的除铁铝盐酸水洗液；(2) Evaporate the hydrochloric acid washing solution at 80° C. to 7.9 L, add ammonia solution to adjust the pH to 5.37, conduct a precipitation reaction, filter the filtrate, and obtain 8.7 L of iron-removing aluminum hydrochloric acid washing solution;
(3)将除铁铝盐酸水洗液送至结晶装置中，结晶装置预先加入2.5g的氯化镁晶种，120rmp搅拌速率下搅拌，通入氯化氢气体进入酸水洗液中，结晶装置一端收集排出溶液的氯化氢，直至氯化镁溶液的酸度为26.8％时，停止通入氯化氢，抽去酸液，即得1.79kg一次氯化镁晶体；(3) Send the iron-removing aluminum hydrochloric acid washing solution to the crystallization device, and the crystallization device adds 2.5g of magnesium chloride seed crystals in advance, stirs at a stirring speed of 120rmp, feeds hydrogen chloride gas into the acid washing solution, and one end of the crystallization device collects and discharges the solution Hydrogen chloride, until the acidity of magnesium chloride solution is 26.8%, stop feeding hydrogen chloride, take out acid solution, obtain 1.79kg primary magnesium chloride crystal;
(4)将氯化镁晶体用纯水溶解得8.7L氯化镁溶液，置于结晶装置中，结晶装置预先加入2.3g的氯化镁晶种，搅拌速率为120rmp下搅拌，通入氯化氢气体进入氯化镁溶液中，结晶装置一端收集排出二次溶液的氯化氢，直至氯化镁溶液的酸度为27.4％时，停止通入氯化氢，抽去酸液，得到1.64kg二次氯化镁晶体，1.7L工业级盐酸与氯化镁晶体酸洗，抽滤酸液得酸洗氯化镁，酸洗氯化镁在分解炉620℃下加热分解185min，得到高纯度氧化镁。(4) Magnesium chloride crystals are dissolved with pure water to obtain 8.7L magnesium chloride solution, which is placed in a crystallization device. The crystallization device adds 2.3 g of magnesium chloride seed crystals in advance, and the stirring speed is stirred at 120 rpm, and hydrogen chloride gas is fed into the magnesium chloride solution to crystallize One end of the device collects and discharges the hydrogen chloride of the secondary solution, until the acidity of the magnesium chloride solution is 27.4%, stops feeding the hydrogen chloride, takes out the acid solution, and obtains 1.64kg of secondary magnesium chloride crystals, pickling with 1.7L industrial grade hydrochloric acid and the magnesium chloride crystals, pumping Filtrate the acid solution to obtain acid-washed magnesium chloride, which is heated and decomposed in a decomposition furnace at 620°C for 185 minutes to obtain high-purity magnesium oxide.
实施例3Example 3
本实施例的镍铁渣中回收氧化镁的方法，包括以下步骤：The method for reclaiming magnesium oxide in the ferronickel slag of the present embodiment may further comprise the steps:
(1)将镍铁渣破碎为镍铁渣碎屑，进行研磨、筛分得1.54kg镍铁渣粉，将镍铁渣粉在420℃干燥、加入8.6L工业级盐酸进行混合，送至密闭容器，在193℃下反应34min，冷却至常温，镍铁渣浆料用76℃的热水水洗2次，抽滤，即得10.3L盐酸水洗液；(1) Crushing ferronickel slag into ferronickel slag debris, grinding and sieving to obtain 1.54kg ferronickel slag powder, drying the ferronickel slag powder at 420°C, adding 8.6L industrial grade hydrochloric acid for mixing, and sending it to a closed The container was reacted at 193°C for 34 minutes, cooled to room temperature, the ferronickel slag slurry was washed twice with hot water at 76°C, and suction filtered to obtain 10.3L of hydrochloric acid washing solution;
(2)将盐酸水洗液在80℃下进行蒸发剩余至7.9L，加氨溶液调pH为5.22，沉淀反应，过滤取滤液，得到10.4L的除铁铝盐酸水洗液；(2) Evaporate the hydrochloric acid washing solution at 80° C. to 7.9 L, add ammonia solution to adjust the pH to 5.22, conduct a precipitation reaction, filter the filtrate, and obtain 10.4 L of iron-removing aluminum hydrochloric acid washing solution;
(3)将除铁铝盐酸水洗液送至结晶装置中，结晶装置预先加入3.0g的氯化镁晶种，120rmp搅拌速率下搅拌，通入氯化氢气体进入酸水洗液中，结晶装置一端收集排出溶液的氯化氢，直至氯化镁溶液的酸度为29.3％时，停止通入氯化氢，抽去酸液，即得2.33kg一次氯化镁晶体；(3) The iron-removing aluminum hydrochloric acid washing solution is sent to the crystallization device, and the crystallization device adds 3.0 g of magnesium chloride seeds in advance, stirs at a stirring rate of 120rmp, feeds hydrogen chloride gas into the acid washing solution, and one end of the crystallization device collects and discharges the solution Hydrogen chloride, when the acidity of magnesium chloride solution is 29.3%, stop feeding hydrogen chloride, take out acid solution, obtain 2.33kg primary magnesium chloride crystal;
(4)将氯化镁晶体用纯水溶解得9.8L氯化镁溶液，置于结晶装置中，结晶装置预先加入3.1g的氯化镁晶种，搅拌速率为120rmp下搅拌，通入氯化氢气体进入氯化镁溶液中，结晶装置一端收集排出溶液的氯化氢，直至氯化镁溶液的酸度为28.3％时，停止通入氯化氢，抽去酸液，得到2.27kg二次氯化镁晶体，2.5L工业级盐酸与氯化镁晶体酸洗，抽滤酸液得酸洗氯化镁，酸洗氯化镁在分解炉620℃下加热分解190min，得到高纯度氧化镁。(4) Magnesium chloride crystals are dissolved with pure water to obtain 9.8L magnesium chloride solution, which is placed in a crystallization device. The crystallization device adds 3.1 g of magnesium chloride seed crystals in advance, and the stirring speed is stirred at 120 rpm, and hydrogen chloride gas is fed into the magnesium chloride solution to crystallize One end of the device collects the hydrogen chloride discharged from the solution until the acidity of the magnesium chloride solution is 28.3%, stops feeding the hydrogen chloride, and removes the acid solution to obtain 2.27 kg of secondary magnesium chloride crystals, pickling with 2.5 L of industrial grade hydrochloric acid and magnesium chloride crystals, and suctioning the acid The solution is acid-washed magnesium chloride, and the acid-washed magnesium chloride is heated and decomposed in a decomposition furnace at 620°C for 190 minutes to obtain high-purity magnesium oxide.
实施例4Example 4
本实施例的镍铁渣中回收氧化镁的方法，包括以下步骤。The method for recovering magnesium oxide from ferronickel slag of the present embodiment comprises the following steps.
(1)将镍铁渣破碎为镍铁渣碎屑，进行研磨、筛分得1.42kg镍铁渣粉，将镍铁渣粉在420℃干燥、加入7.2L工业级盐酸进行混合，送至密闭容器，加热至217℃下反应35min，冷却至常温，镍铁渣浆料用83℃的热水水洗2次，抽滤，即得9.6L盐酸水洗液；(1) Crushing ferronickel slag into ferronickel slag debris, grinding and sieving to obtain 1.42kg ferronickel slag powder, drying the ferronickel slag powder at 420°C, adding 7.2L industrial grade hydrochloric acid for mixing, and sending it to a closed The container was heated to 217°C and reacted for 35 minutes, cooled to room temperature, the ferronickel slag slurry was washed twice with hot water at 83°C, and suction filtered to obtain 9.6L hydrochloric acid washing solution;
(2)将盐酸水洗液在80℃下进行蒸发剩余至8.4L，加氨溶液调pH为5.48，沉淀反应，过滤取滤液，得到9.8L的除铁铝盐酸水洗液；(2) Evaporate the hydrochloric acid washing solution at 80° C. to 8.4 L, add ammonia solution to adjust the pH to 5.48, conduct precipitation reaction, filter and take the filtrate, and obtain 9.8 L of iron-removing aluminum hydrochloric acid washing solution;
(3)将除铁铝盐酸水洗液送至结晶装置中，结晶装置预先加入3.8g的氯化镁晶种，120rmp搅拌速率下搅拌，通入氯化氢气体进入酸水洗液中，结晶装置一端收集排出溶液的氯化氢，直至氯化镁溶液的酸度为28.8％时，停止通入氯化氢，抽去酸液，即得2.17kg一次氯化镁晶体；(3) Send the iron-removing aluminum hydrochloric acid washing solution to the crystallization device, and the crystallization device adds 3.8g of magnesium chloride seed crystals in advance, stirs at a stirring rate of 120rmp, feeds hydrogen chloride gas into the acid washing solution, and one end of the crystallization device collects and discharges the solution Hydrogen chloride, when the acidity of magnesium chloride solution is 28.8%, stop feeding hydrogen chloride, take out acid solution, obtain 2.17kg primary magnesium chloride crystal;
(4)将氯化镁晶体用纯水溶解得8.7L氯化镁溶液，置于结晶装置中，结晶装置预先加入3.6g的氯化镁晶种，搅拌速率为120rmp下搅拌，通入氯化氢气体进入氯化镁溶液中，结晶装置一端收集排出溶液的氯化氢，直至氯化镁溶液的酸度为29.73％时，停止通入氯化氢，抽去酸液，得到2.12kg二次氯化镁晶体，1.8L工业级盐酸与氯化镁晶体酸洗，抽滤酸液得酸洗氯化镁，酸洗氯化镁在分解炉620℃下加热分解197min，得到高纯度氧化镁。(4) Magnesium chloride crystal is dissolved with pure water to obtain 8.7L magnesium chloride solution, is placed in the crystallization device, the magnesium chloride seed crystal of 3.6g is added in advance in the crystallization device, stirring speed is stirred under 120rmp, feeds hydrogen chloride gas and enters in the magnesium chloride solution, crystallization One end of the device collects the hydrogen chloride discharged from the solution until the acidity of the magnesium chloride solution is 29.73%, stops feeding the hydrogen chloride, and removes the acid solution to obtain 2.12 kg of secondary magnesium chloride crystals, pickling with 1.8 L of industrial grade hydrochloric acid and magnesium chloride crystals, and suctioning the acid The solution is acid-washed magnesium chloride, which is heated and decomposed in a decomposition furnace at 620°C for 197 minutes to obtain high-purity magnesium oxide.
表1实施例1-4数据对比Table 1 embodiment 1-4 data comparison
Figure PCTCN2022095677-appb-000001
Figure PCTCN2022095677-appb-000001
利用电感耦合等离子发射光谱仪(ICAP-7200，美国赛默飞公司)测定氯化镁晶体以及热分解后氧化镁纯度，计算公式为：Utilize the inductively coupled plasma emission spectrometer (ICAP-7200, U.S. Thermo Fisher) to measure the magnesium chloride crystal and the magnesium oxide purity after thermal decomposition, and the calculation formula is:
一次氯化镁晶体中镁的质量(kg)＝一次氯化镁晶体总质量×待测的氯化镁晶体酸溶液中镁的浓度×稀释倍数/待测的氯化镁晶体质量；The quality (kg) of magnesium in the primary magnesium chloride crystal = the primary magnesium chloride crystal total mass * the concentration of magnesium in the magnesium chloride crystal acid solution to be measured * the dilution factor/the magnesium chloride crystal quality to be measured;
二次氯化镁晶体中镁的质量(kg)＝二次氯化镁晶体总质量×待测的氯化镁晶体酸溶液中镁的浓度×稀释倍数/待测的氯化镁晶体质量；The quality (kg) of magnesium in the secondary magnesium chloride crystal = the secondary magnesium chloride crystal total mass * the concentration of magnesium in the magnesium chloride crystal acid solution to be measured * the dilution factor/magnesium chloride crystal quality to be measured;
酸洗后镁晶体中杂质降低量(％)＝(1-酸洗后镁晶体中杂质浓度/酸洗前镁晶体中杂质浓度)×100％；Impurity reduction in the magnesium crystal after pickling (%)=(1-impurity concentration in the magnesium crystal after pickling/impurity concentration in the magnesium crystal before pickling) × 100%;
热分解后氧化镁纯度(％)＝二次氯化镁晶体热分解后氧化镁质量/二次氯化镁晶体热分解后总质量×100％；Magnesium oxide purity after thermal decomposition (%) = magnesium oxide quality after thermal decomposition of secondary magnesium chloride crystals/total mass after thermal decomposition of secondary magnesium chloride crystals × 100%;
镁的回收率(％)＝二次氯化镁晶体热分解后氧化镁的质量×氧化镁纯度×0.6/镍铁渣中镁的质量×100％。Magnesium recovery rate (%)=mass of magnesium oxide after thermal decomposition of secondary magnesium chloride crystal×magnesia purity×0.6/mass of magnesium in ferronickel slag×100%.
从表1中可得，实施例1-4中二次氯化镁晶体经酸洗后，杂质含量分别降低了44.6％、38.5％、50.7％、48.9％，氧化镁的纯度分别为98.3％、98.7、97.1％、97.4％，杂质含量均<3.0％，含杂量低；实施例1-4镍铁渣中镁的回收率91.2％、89.4％、90.7％、92.0％，回收率较高。因此，利用本发明镍铁渣回收的氧化镁具有高纯度高回收率的特点。Can get from table 1, after the secondary magnesium chloride crystal is pickled in embodiment 1-4, impurity content reduces respectively 44.6%, 38.5%, 50.7%, 48.9%, and the purity of magnesium oxide is respectively 98.3%, 98.7, 97.1%, 97.4%, impurity content <3.0%, low impurity content; the recovery rate of magnesium in the ferronickel slag of Examples 1-4 is 91.2%, 89.4%, 90.7%, 92.0%, the recovery rate is relatively high. Therefore, the magnesium oxide recovered by using the ferronickel slag of the present invention has the characteristics of high purity and high recovery rate.
上面结合附图对本发明实施例作了详细说明，但是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。此外，在不冲突的情况下，本发明的实施例及实施例中的特征可以相互组合。The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments, and within the scope of knowledge of those of ordinary skill in the art, various modifications can be made without departing from the spirit of the present invention. Variety. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other if there is no conflict.

Claims (10)

  1. 一种镍铁渣中回收氧化镁的方法，其特征在于，包括以下步骤：A method for reclaiming magnesium oxide in ferronickel slag, is characterized in that, comprises the following steps:
    (1)向镍铁渣中加入盐酸混合，加热反应，固液分离，取液相，即得酸水洗液；(1) adding hydrochloric acid to ferronickel slag to mix, heating for reaction, separating solid and liquid, taking the liquid phase to obtain acid washing solution;
    (2)将所述酸水洗液进行浓缩，加碱调pH，进行沉淀反应，分离出液相，得到除铁铝盐酸水洗液；(2) Concentrating the acid washing liquid, adding alkali to adjust the pH, carrying out precipitation reaction, separating the liquid phase, and obtaining the iron-removing aluminum hydrochloric acid washing liquid;
    (3)将所述除铁铝盐酸水洗液加入晶种中搅拌，通入氯化氢，进行一次结晶，固液分离，即得氯化镁晶体；(3) Add the washing solution of iron-removing aluminum hydrochloric acid into the seed crystal and stir, feed hydrogen chloride, carry out primary crystallization, and separate solid and liquid to obtain magnesium chloride crystals;
    (4)将所述氯化镁晶体进行二次结晶，所得晶体加热分解，得到氧化镁。(4) The magnesium chloride crystal is subjected to secondary crystallization, and the obtained crystal is heated and decomposed to obtain magnesium oxide.
  2. 根据权利要求1所述的方法，其特征在于，步骤(1)中，所述镍铁渣和酸的液固比为10：(40～80)ml/g。The method according to claim 1, characterized in that in step (1), the liquid-solid ratio of the ferronickel slag and acid is 10: (40-80) ml/g.
  3. 根据权利要求1所述的方法，其特征在于，步骤(1)中，所述加热反应的温度为150～240℃。The method according to claim 1, characterized in that, in step (1), the temperature of the heating reaction is 150-240°C.
  4. 根据权利要求1所述的方法，其特征在于，步骤(1)中，所述固液分离前还包括进行水洗，所述水洗采用的温度为50～95℃的水，水洗1～2次。The method according to claim 1, characterized in that, in step (1), before the solid-liquid separation, water washing is also included, and the water washing uses water at a temperature of 50-95°C for 1-2 times.
  5. 根据权利要求1所述的方法，其特征在于，步骤(2)中，所述浓缩为：蒸发部分水量至酸水洗液水含量减少200～400ml/L。The method according to claim 1, characterized in that in step (2), the concentration is: evaporating part of the water until the water content of the acid washing solution is reduced by 200-400ml/L.
  6. 根据权利要求1所述的方法，其特征在于，步骤(2)中，所述调pH是将酸水洗液的pH调节至3.0～5.5。The method according to claim 1, characterized in that, in step (2), the pH adjustment is to adjust the pH of the acid washing solution to 3.0-5.5.
  7. 根据权利要求1所述的方法，其特征在于，步骤(2)中，所述加碱调pH使用的碱液为氨水。The method according to claim 1, characterized in that, in step (2), the lye used to adjust the pH by adding alkali is ammonia water.
  8. 根据权利要求1所述的方法，其特征在于，步骤(3)中，所述晶种为氯化镁晶种。The method according to claim 1, characterized in that, in step (3), the seed crystal is a magnesium chloride seed crystal.
  9. 根据权利要求1所述的方法，其特征在于，步骤(4)中，所述加热分解前还包括对所得晶体进行酸洗。The method according to claim 1, characterized in that, in step (4), before the thermal decomposition, it also includes pickling the obtained crystals.
  10. 根据权利要求1所述的方法，其特征在于，步骤(4)中，所述二次结晶的具体步骤为将氯化镁晶体加水溶解得到氯化镁溶液，再加入晶种中搅拌，通入气体，进行二次结晶，得到氯化镁晶体。The method according to claim 1, characterized in that, in step (4), the specific step of the secondary crystallization is to dissolve the magnesium chloride crystals with water to obtain a magnesium chloride solution, then add in the seed crystals and stir, feed gas, and carry out the secondary crystallization. Secondary crystallization to obtain magnesium chloride crystals.
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