CN115161478A - Utilizing MgO/SiO in silicon-magnesium-containing minerals 2 Method for extracting magnesium metal through carbon in-situ high-temperature reduction reaction - Google Patents

Utilizing MgO/SiO in silicon-magnesium-containing minerals 2 Method for extracting magnesium metal through carbon in-situ high-temperature reduction reaction Download PDF

Info

Publication number
CN115161478A
CN115161478A CN202210193948.8A CN202210193948A CN115161478A CN 115161478 A CN115161478 A CN 115161478A CN 202210193948 A CN202210193948 A CN 202210193948A CN 115161478 A CN115161478 A CN 115161478A
Authority
CN
China
Prior art keywords
magnesium
sio
mgo
powder
acid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210193948.8A
Other languages
Chinese (zh)
Inventor
朱萍
夏斌
刘强
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Shanghai for Science and Technology
Original Assignee
University of Shanghai for Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Shanghai for Science and Technology filed Critical University of Shanghai for Science and Technology
Priority to CN202210193948.8A priority Critical patent/CN115161478A/en
Publication of CN115161478A publication Critical patent/CN115161478A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/10—Dry methods smelting of sulfides or formation of mattes by solid carbonaceous reducing agents
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0006—Making spongy iron or liquid steel, by direct processes obtaining iron or steel in a molten state
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0066—Preliminary conditioning of the solid carbonaceous reductant
    • 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
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
    • C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
    • C22B3/08—Sulfuric acid, other sulfurated acids or salts thereof
    • 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
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

The invention discloses a method for utilizing MgO/SiO in silicon-magnesium-containing mineral 2 Method for extracting magnesium metal by carbon in-situ high-temperature reduction reaction, and method for extracting magnesium metal from SiO of silicon-magnesium-containing mineral or tailings by using carbothermic reduction method 2 Reducing the silicon into silicon and then reducing the magnesium oxide into magnesium metal, belonging to the fields of chemical industry, agriculture, metallurgy, metal materials, solid wastes and environment. The invention uses acid cross flow to leach the minerals or tailings containing silicon and magnesium, the liquid after filtration and separation is extracted or precipitated to obtain ferric hydroxide, and the ferric hydroxide is calcined into ferric oxide. After iron removal, containCrystallizing the magnesium leaching solution to obtain a magnesium crystal; reacting the magnesium crystal with ammonia water to obtain Mg (OH) 2 And (NH) 4 ) 2 SO 4 Handle of bicycle Mg (OH) 2 Calcining to prepare MgO; filtering the separated solid residue SiO 2 (or SiO) 2 And iron oxide) and carbon to prepare molten ferrosilicon; the molten ferrosilicon product reacts with MgO and additive or cosolvent under vacuum condition to obtain Mg vapor, and the Mg product is obtained through condensation, so that the cost is low, and the industrial value is remarkable.

Description

Utilizing MgO/SiO in silicon-magnesium-containing minerals 2 By carbon in situ high temperature reductionMethod for extracting metal magnesium by primary reaction
Technical Field
The invention relates to a method for preparing SiO from minerals or tailings containing silicon and magnesium by using a carbothermic reduction method 2 A method for reducing silicon and then reducing magnesium oxide into magnesium metal belongs to the fields of chemical industry, agriculture, metallurgy, metal materials, solid wastes and environment.
Background
In the latter half of the 20 th century, fused salt electrolysis is mainly used in world magnesium production. In 2000, over 80% of the world's magnesium was produced by electrolysis, followed by semi-continuous process, which is third of Pidgeon process. The molten salt electrolysis method is an important method for producing metal magnesium, and MgCl is mainly used 2 -NaCI-KCl-CaCl 2 -CaF 2 Or MgCl 2 -NaCI-KCl-CaF 2 Electrolyzing magnesium chloride at 680-750 deg.C by molten salt system to obtain chlorine at anode, and separating out liquid magnesium at cathode, wherein the anode material is graphite, and the cathode is steel; when the chloride fused salt is used for electrolyzing and smelting magnesium, the existence of impurities in the electrolyte can cause the changes of physical and chemical properties in the electrolyte and the electrochemical process of an electrode, thereby destroying the normal circulation of the electrolyte, the magnesium and the chlorine and greatly reducing the current efficiency of electrolysis.
The bischofite dehydration is a complex chemical process with strong heat absorption and high energy consumption, and has no advantages compared with the method for producing magnesium chloride by the chlorination of magnesite with almost no energy consumption. And the magnesium chloride prepared by dehydrating bischofite always contains a small amount of water, so that the electrolytic cell generates more waste residues harmful to the environment, the current efficiency is low, more harmful gas HCl is generated, and the consumption of the graphite anode is high. At present, the world uses brine to smelt magnesium in a small number of plants, and due to the rising price of energy, the production cost is increased, and some plants are closed. The newly built electrolytic magnesium plants mostly use anhydrous magnesium chloride prepared by the chlorination of magnesite as a raw material. The design and process technology of foreign magnesium chloride molten salt electrolytic cells are greatly improved, and the Ex2 electrolytic cell technology of Canadian aluminum industry company is the most representative. The current intensity is 650kA, the daily yield of a single groove is 6.18t, the current efficiency is 87 percent, the direct current power consumption is 10000kWh/t & Mg, and the alternating current power consumption is 11000kWh/t & Mg. In addition, in the process of producing the electrolytic magnesium by taking anhydrous magnesium chloride or anhydrous potassium carnallite as raw materials, 2.85t of chlorine gas is produced at the same time when 1t of electrolytic crude magnesium is obtained. As is well known, in magnesium electrolysis plants and magnesium-titanium combined enterprises, by-product chlorine is collected and processed to form good magnesium-chlorine circulation, which is an important guarantee for improving the surrounding atmospheric environment, improving the economic benefit of electrolysis production and ensuring the continuous magnesium electrolysis.
The canadian scientist pijiang (l.m. pidgeon) in 1941 invented a process for smelting magnesium by silicothermic reduction, called pijiang method. The process comprises the steps of grinding calcined dolomite and ferrosilicon into fine powder according to a certain proportion, pressing the calcined dolomite into briquettes (the calcined dolomite is easy to absorb water, so that the briquettes absorb water slowly), placing the briquettes into a distillation retort made of heat-resistant alloy, reducing the briquettes at the temperature of 150-1200 ℃ and under the condition of 1-13 Pa to obtain magnesium vapor, then condensing and crystallizing the magnesium vapor into crude magnesium, and refining the crude magnesium to obtain magnesium ingots. The reduction reaction is as follows:
2(CaO·MgO) fixing device +Si(Fe) Fixing device ＝2Mg Qi (Qi) +2CaO·SiO 2 fixation +Fe(Si) Fixing device (1)
The Pidgeon process is simple, less in investment, high in product quality, but not capable of continuous production, and higher in cost than the electrolytic process.
The reducing agent of the metal reduction method has higher price, and the reduction preparation of the metal magnesium by using the cheap carbonaceous material is always paid attention by people, so that the search for a new magnesium smelting process has very important significance. The carbothermic reduction method is an alternative thermal method magnesium-smelting reduction technology besides the Pidgeon method. The carbothermic reduction method is to reduce magnesium oxide or other calcined magnesite (magnesite, dolomite, serpentine, sepiolite, talc, forsterite, bischofite, carnallite and brucite) at high temperature by taking carbonaceous materials as a reducing agent to obtain magnesium vapor, and to obtain solid magnesium metal after condensation. The carbothermic reduction reaction may be represented by formula (2):
MgO(s)+C(s)＝Mg(g)+CO(g)(2)
however, the gaseous products of this process, which are formed by the reaction at high temperatures, partly undergo a reversible reaction. Many scholars in foreign countries have conducted a series of large, medium and small studies on the preparation of metal magnesium by carbothermic method under two conditions of normal pressure and vacuum, but the industrial production has not been realized yet due to some technical difficulties. At the present stage, the condensation experimental research for preparing metal magnesium by a vacuum carbothermic method at home and abroad is still limited to laboratory miniaturization experiments, and meanwhile, the scheme provided by foreign scholars for condensing metal magnesium vapor has the defects of high equipment requirement, large investment, complex process flow and difficult industrial popularization.
In foreign research on magnesium smelting by carbothermic processes, the work done in australia is the most prominent and detailed. While the Laval nozzle is used for carrying out a supersonic condensation experiment, the Laval nozzle utilizes simulation to determine the process conditions of nozzle temperature and air injection pressure on controlling magnesium vapor liquid phase nucleation, evaluates the influence of supersonic speed on particle size (powdery magnesium) under different operation processes and different nozzle shapes, and solves the problem of nozzle blockage after optimizing the external appearance of the nozzle. However, the process conditions of high temperature and high pressure have extremely high requirements for industrial production, so that the process has not been applied industrially.
The national engineering laboratory of vacuum metallurgy of Kunming university has carried out small-scale research on the vacuum thermal decomposition of dolomite and the vacuum carbothermic reduction of magnesium oxide, because the reduction temperature is difficult to control, and the distance between the reduction chamber and the condensation chamber is too far, the condensation temperature is too low, therefore the crystal magnesium that obtains is all powdery, it becomes unsafe factor to explode easily.
For the magnesium smelting process by carbon reduction reaction, the key technology is magnesium vapor condensation. The MgO impurities are obtained when the magnesium vapor condenses too quickly (e.g., supersonic cooling, avoids the occurrence of inverse equation (2), but produces powdered magnesium, which is prone to explosion. When the magnesium vapor condenses more slowly, crystalline magnesium is produced, along with inverse equation (2).
China has huge reserves of minerals containing silicon and magnesium, such as serpentine, magnesite, dolomite, sepiolite, talc, forsterite, bischofite, carnallite and the like. The serpentine mineral has a chemical formula represented by Mg 6 Si 4 O 10 (OH) 8 1:1 lamellar tectosilicate minerals. Serpentine belongs toIn weakly alkaline minerals, where SiO 2 The content is more than 30 percent. Magnesite is carbonate mineral, mainly composed of MgCO 3 Wherein the MgO content can reach 47%, siO 2 The content can reach 8 percent. Dolomite is also carbonate mineral and its chemical component is CaMg (CO) 3 ) 2 . The MgO content reaches more than 21 percent. Sepiolite is a fibrous hydrous magnesium-rich silicate natural mineral with a chemical formula of Mg 8 (OH 2 ) 4 [Si 6 O 15 ] 2 (OH) 4 ·8H 2 O, wherein SiO 2 The content can reach 54-60%, and the MgO content can reach 20%. Talc is a common silicate mineral with a layered structure and has a chemical formula of Mg 6 Si 8 O 20 (OH) 4 The talc is generally in the form of a block, a leaf, a fiber or a radial, and has an MgO content of 31% and SiO content 2 The content can reach 63 percent. The forsterite is a mineral mainly containing magnesium oxide and silicon dioxide, and has a theoretical chemical formula of 2 MgO. SiO 2 . Wherein the MgO content can reach 57 percent, and the SiO 2 The content can reach 42 percent. Bischofite contains Mg (11.96%) and MgCl as main component 2 ·6H 2 And O. The carnallite is halide mineral and has KCl MgCl as main component 2 ·6H 2 O, 8.7 percent of magnesium.
Taking serpentine as an example, the comprehensive utilization of serpentine tailings is an urgent problem to be solved because no good resource development technology exists. Meanwhile, as the serpentine has foliated or phosphorus flake crystals and large differentiation layers, china is open-pit mining, a large amount of crushed ore with the granularity of 2-3 cm is generated in the mining process, generally called serpentine powder ore or tailing, occupies about 1/3-1/2 of the mining amount, is usually discarded as waste, wastes mineral resources and occupies mining surfaces and farmlands.
Disclosure of Invention
In order to solve the problems of the prior art, the invention aims to overcome the defects of the prior art and provide a method for utilizing MgO/SiO in silicon-magnesium-containing minerals 2 Method for extracting magnesium metal by carbon in-situ high-temperature reduction reaction, and method for separating silicon and magnesium by using acid to leach minerals or tailings containing silicon and magnesiumThe acidity can be reduced on the one hand by leaching the minerals or tailings containing silicon and magnesium through cross flow; on the other hand, the method can effectively enrich magnesium and iron ions in the leaching solution, the number of cross-flow leaching can be 1-10, and the pH value of the leaching solution can be adjusted to be 0-5. Concentrating and crystallizing the cross-flow leaching solution to obtain a magnesium salt crystal, circularly leaching silicon-magnesium-containing minerals or tailings by using the leaching solution, and precipitating or extracting and separating when iron ions are enriched to be separated. The magnesium salt crystal reacts with ammonia water to obtain magnesium hydroxide and ammonium salt, and then the magnesium hydroxide is calcined to obtain magnesium oxide which is used as a raw material for smelting magnesium. The ammonium salt is used as raw material of chemical fertilizer for agriculture. Filtering the leached SiO 2 The residue, subjected to carbon reduction to produce crude silicon, which is used to reduce magnesium oxide to achieve the production of magnesium metal.
In order to achieve the purpose, the invention adopts the following technical scheme:
MgO/SiO utilizing silicon-magnesium containing mineral 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction comprises the following steps: pretreating silicon-magnesium-containing mineral or tailings into mineral powder, leaching the mineral powder with acid, and filtering to separate solid from liquid to obtain SiO 2 The solid residue and the magnesium-containing leaching solution are concentrated to obtain a magnesium salt crystallization product, the magnesium salt crystallization product is reacted with alkali to obtain magnesium hydroxide, and the magnesium hydroxide is calcined and converted to generate MgO powder;
separating iron in the magnesium-containing leaching solution by a precipitation or extraction process to obtain an iron hydroxide precipitate, calcining and converting to generate iron oxide, and ball-milling the iron oxide precipitate into iron oxide powder;
the filtered and separated SiO 2 Drying the solid residue, and ball-milling into SiO 2 Powder;
under the condition of adding the iron oxide powder, the SiO is added 2 Putting the powder and carbon powder into a vacuum reduction furnace, and carrying out high-temperature reduction reaction to generate a molten ferrosilicon product;
under the in-situ condition, the MgO powder is sprayed into the molten ferrosilicon to be reduced to generate Mg steam, and a magnesium metal product is obtained through condensation.
Preferably, the magnesium-containing leach solution comprises at least one metal ion selected from the group consisting of iron ions, nickel ions and aluminum ions.
Preferably, the concentration process of the magnesium-containing leaching solution adopts cross-flow leaching or evaporation treatment.
Preferably, the base includes at least one of ammonia, a hydroxide, and a carbonate.
Preferably, the iron oxide comprises iron oxide obtained from an oxidation treatment of waste iron, an acidolysis precipitation calcination treatment of waste iron, or directly with industrial pure iron oxide.
Preferably, the siliceous magnesium mineral includes at least one mineral of serpentine, magnesite, dolomite, sepiolite, talc, forsterite, bischofite and carnallite and tailings thereof.
Preferably, the acid is any one of inorganic acid or mixed acid of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and carbonic acid, or any one of organic acid or mixed acid of oxalic acid, tartaric acid, acetic acid, boric acid, citric acid and formic acid; or the acid is a mixed acid of the inorganic acid and the organic acid.
Preferably, the SiO is treated with the addition of the iron oxide 2 Putting the powder and the carbon powder into a vacuum reduction furnace to carry out high-temperature reduction reaction to generate a molten ferrosilicon product; the grain diameter of the mixed powder is 10-200 meshes, and the component proportion of the mixed powder is as follows: siO 2 2 Powder, or SiO 2 The mixture of the powder and the ferric oxide is 2-5kg; 0.3-1kg of charcoal, or 0-1 kg of anthracite or bituminous coal, or 0.1-0.9 kg of petroleum coke, or 1-4 kg of sawdust; the power of the vacuum furnace is 1-2000MW, the smelting time is 1-40 hours, and the furnace temperature is controlled within the range of 1000-2000 ℃ to obtain a molten ferrosilicon product; the silicon content of the molten ferrosilicon product is 70-95% (w) by mass, and the iron content of the molten ferrosilicon product is 1-30% (w) by mass.
Preferably, under in-situ conditions, the MgO powder is sprayed into the molten ferrosilicon, and the reduction reaction conditions of the molten ferrosilicon product and MgO include: the particle size of MgO powder is 10-200 meshes, the reaction temperature is 700-1800 ℃, and the proportion of the raw materials for vacuum smelting of magnesium is calculated according to the mass proportion under the condition of negative pressure of 1-20 Pa:
CaO + MgO (or MgO), reducing agent and additive (or fluxing agent) in a mass ratio of 90-110;
the reducing agent is silicon powder, ferrosilicon powder or a mixture of silicon and iron powder.
Preferably, the additives and fluxing agents may be used alone or in admixture; the additive adopts fluorite powder and MgF 2 At least one of NaF and inorganic fluoride; the fluxing agent adopts Al 2 O 3 And CaO.
Compared with the prior art, the invention has the following obvious and prominent substantive characteristics and remarkable advantages:
1. the invention uses the minerals or tailings containing silicon and magnesium as raw materials to prepare the magnesium metal product, thereby reducing the resource waste and realizing the comprehensive utilization of the minerals or tailings;
2. the invention uses silicon-magnesium-containing minerals or tailings as raw materials to prepare the magnesium metal product, the industrial cost is low, and the byproduct ammonium salt of the method is used as the raw material of the fertilizer and is used in agriculture;
3. the method is simple, high in production efficiency and suitable for popularization and application.
Drawings
FIG. 1 shows the reduction of SiO with carbon after the acid leaching separation of Si and Mg according to the invention 2 The process flow schematic diagram of obtaining magnesium by reducing MgO from the obtained crude silicon.
Detailed Description
MgO/SiO utilizing silicon-magnesium containing mineral 2 The invention relates to a method for extracting metal magnesium by carbon in-situ high-temperature reduction reaction, which adopts any one of the following implementation modes:
the first embodiment is as follows:
ball-milling pretreatment is carried out on silicon-magnesium-containing minerals or tailings thereof, the size of particles completely passes through a sieve of 100-200 meshes, the mineral powder is divided into two parts, one part is subjected to calcination pretreatment, and the treatment temperature range is as follows: the temperature is 200-850 ℃ and the time is 15-180 minutes. Adding the pretreated mineral powder into a sulfuric acid solution for leaching reaction, wherein the solid-to-liquid ratio is 1:1-1 and the stirring speed is as followsThe temperature is 10-500 rpm, the temperature is 1-100 ℃, the time is 1-800 min, and the concentration of the sulfuric acid is controlled to be 0.5-98% (w). By cross-flow leaching of the mineral powder, on the one hand, acidity can be reduced; on the other hand, the concentration of magnesium and iron ions in the leaching solution can be effectively enriched, and the number of times of the cross-flow leaching can be 1-10. The filtering process can realize the separation of the leaching solution and the solid residue to obtain the porous SiO 2 。
Treating the filtered leaching solution, separating out iron by precipitation when iron in the cross-flow leaching solution is enriched to a certain degree, wherein the precipitator usually selects alkali and sulfide; wherein the alkali is at least one of sodium hydroxide, ammonia water and sodium carbonate; the sulfide adopts ammonium sulfide and Na 2 At least one of S. Alternatively, separation may be achieved by extraction processes, with P 507 Or naphthenic acid extraction of iron. Then, ferric hydroxide can be obtained through precipitation treatment, and ferric oxide is generated through calcination at 200-1000 ℃. If the mineral has no iron element, the iron oxide can be obtained by oxidizing waste iron or acid leaching and precipitating the waste iron and then roasting, or industrial pure iron oxide is directly used.
Treating the magnesium-containing leaching solution with iron removed by crystallization evaporation process or reduced pressure evaporation crystallization process to obtain magnesium sulfate heptahydrate crystal (MgSO) 4 ·7H 2 O). Treating the obtained magnesium sulfate crystals with ammonia water, and obtaining magnesium hydroxide and ammonium sulfate through precipitation reaction shown in equation (1). Initial Mg 2+ The ion concentration is 1.1-1.7 moL/L, the molar ratio of ammonia and magnesium is 1:1-8:1, the reaction temperature is 10-80 ℃, and the reaction time is 10-60 min. In Mg 2+ The concentration of the magnesium hydroxide is more than 2mol/L, the molar ratio of the magnesium hydroxide to the ammonia is 1:1-8:1, and the reaction temperature is 40-60 ℃. Then, filtering and separating, and drying the precipitate to obtain Mg (OH) 2 Evaporating the filtrate solution or evaporating under reduced pressure to obtain (NH) 4 ) 2 SO 4 。
MgSO 4 +2NH 4 OH＝(NH 4 ) 2 SO 4 +Mg(OH) 2 ↓ (1)
Mg(OH) 2 Calcining at 100-1200 deg.c for 10-600 min to obtain MgO product.
During the silicon melting process, the reducing agent for reducing the silicon oxide is mainly derived from carbon. The reaction capacity varies from carbonaceous feedstock to carbonaceous feedstock. However, it has not been clear for a long time which factors influence the reactivity. The reducing agent generally used contains a certain amount of moisture, ash and volatile components, the reducing agent is at least one of charcoal, oil coke and bituminous coal, and the content of fixed carbon is generally only 60-80% and at most about 95%. During the reduction reaction, water and volatile components are evaporated and volatilized, while ash is remained, wherein one part is reduced into simple substances, and the other part enters the product in the form of oxides to reduce the quality of the product.
During the reduction of silicon oxide by carbon, the change from silicon oxide to silicon is in the following order:
Figure BDA0003526183030000061
wherein O is SiO2 Is as SiO 2 Oxygen formed by the reaction of SiO + O. In the overall process, the silica decomposes into silicon monoxide and oxygen, and the silicon carbide formation is destroyed, which are two important intermediate steps.
Silicon smelting is carried out in a vacuum reduction furnace, and the filtered porous SiO is 2 Washing and drying the solid residue, and weighing SiO 2 Solid residues or SiO 2 1-5kg of mixture of iron oxide and coke, 0.1-4 kg of coke or 0.3-4kg of charcoal, or 0-4 kg of anthracite or bituminous coal, or 0.1-3 kg of petroleum coke, or 1-5kg of wood chips. The power of the vacuum furnace is 1-2000MW, the smelting time is 1-40 hours, the furnace temperature can be controlled within the range of 1000-2000 ℃, and the molten ferrosilicon reducing agent can be prepared and used for reducing MgO to prepare magnesium metal. In the molten ferrosilicon product, the mass content of silicon is 70-95% (w), and the mass content of iron is 1-30% (w).
In the vacuum furnace, residual gases CO and CO in the furnace are discharged 2 Under the vacuum condition, the MgO (or CaO) powder subjected to calcination and drying treatment is sprayed into the molten ferrosilicon product, and the particle size of the MgO powder is 10-200The reaction temperature is 700-1800 ℃, the negative pressure is 1-20Pa, the generated magnesium is in a gas state, the magnesium steam is condensed into solid magnesium by a cooling device, and the solid magnesium is taken out periodically. In addition, the residue of the reaction of the molten ferrosilicon with the MgO powder is discharged from the furnace. Then, siO is added 2 And (3) putting the solid residues and a carbon reducing agent containing ferric oxide into a vacuum furnace to react to generate a ferrosilicon melt, and then adding magnesium oxide to react to generate magnesium metal, thereby forming a cyclic reaction. The reaction makes full use of the reaction between the high-temperature ferrosilicon melt and the magnesium oxide, and saves energy.
The vacuum smelting magnesium comprises the following raw materials in parts by mass of 90-110 (CaO + MgO (or MgO only) and 2-3 (CaO + MgO) and a reducing agent and an additive), wherein the reducing agent comprises silicon powder or ferrosilicon powder or silicon + iron powder. The particle size ratio of the raw materials is that silicon powder or ferrosilicon powder or silicon and iron powder is more than 80% (-100); fluorite powder is more than 80% (-120 meshes); (CaO + MgO (or MgO only) > 80% (-80 mesh.) the density of the compact is generally controlled to 1.9g/cm 3 ～2.1g/cm 3 . In addition, al may be added in a mass ratio 2 O 3 The amount of the reaction flux added is 1 to 50% by weight of MgO (w). The reduction process is a process of putting the prepared briquettes into a reduction tank reactor, namely a tank made of heat-resistant steel, and carrying out reduction reaction under the conditions of negative pressure of 10Pa and temperature of 1100-1300 ℃, wherein the heating mode comprises external heating and internal heating. During the reduction reaction, si in ferrosilicon reduces magnesium oxide (MgO) in the agglomerates, and the magnesium produced is in a gaseous state (T) B Mg = 1090-1107 ℃), a cylindrical condenser is arranged at the cold end of the reduction tank, and the precipitated magnesium vapor enters the outside of the furnace at the front end of the reduction tank after escaping and is precipitated with crude magnesium, namely crystallized magnesium, and presents crown crystals, and then the metal magnesium with high purity is obtained by refining.
Detailed description of the invention
Cross-flow leaching of silicon-magnesium-containing minerals and tailings thereof by using other acids such as hydrochloric acid and the like:
adding the pretreated mineral powder into a hydrochloric acid solution (inorganic acids such as nitric acid, phosphoric acid and carbonic acid, and organic acids such as oxalic acid, tartaric acid, acetic acid, citric acid and formic acid) for leaching reaction, wherein the solid-liquid ratio is 1:1-100, the stirring speed is 10-500 rpm, the temperature is 1-100 ℃, the time is 1-800 min, the concentration of hydrochloric acid is controlled at 1-37 wt.%, or 0.5-63 wt.% of nitric acid, 0.01-0.033 mol/L of carbonic acid, 1-98 wt.% of phosphoric acid, 5-17.5 mol/L of acetic acid, 5-30 mol/L of boric acid, 1-98 wt.% of oxalic acid, 1-98 wt.% of formic acid, 1-98 wt.% of citric acid or 1-98 wt.% of tartaric acid is adopted. The mineral powder is leached by cross flow, and the number of times of the cross flow leaching can be 1 to 10 times.
Hydrochloric acid and other acid leaching magnesium-containing minerals and magnesium-containing crystallization products of tailings thereof:
carrying out solid-liquid separation after cross-flow leaching, and treating the leached liquid containing magnesium with iron removed by a crystallization and evaporation process (or a reduced pressure evaporation and crystallization process) to obtain a magnesium chloride hexahydrate crystal MgCl 2 ·6H 2 O、Mg(NO 3 ) 2 ·6H 2 O、Mg(CO 3 ) 2 ·3H 2 O、 Mg(CH 3 COO) 2 ·4H 2 At least one magnesium salt of O, magnesium phosphate, magnesium citrate and magnesium borate. And respectively reacting the crystallized products of magnesium nitrate, magnesium chloride and magnesium phosphate with alkali, wherein the alkali adopts ammonia water or sodium hydroxide to generate magnesium hydroxide precipitate, and then calcining to obtain the MgO product. The MgO product can be obtained by respectively calcining magnesium acetate, magnesium citrate, magnesium formate, magnesium tartrate and magnesium oxalate. The temperature for obtaining magnesium oxide by calcining the magnesium salt of the organic matter is lower, for example, the temperature for obtaining magnesium oxide by calcining magnesium oxalate is 600 ℃, magnesium acetate is heated to 350 ℃ to lose Cheng Yanghua magnesium hydrate, magnesium formate starts to dehydrate to magnesium oxide at the temperature of 130-240 ℃, the decomposition temperature of magnesium borate is higher and is 1000 ℃.
Other embodiments are the same as the first embodiment.
The above-described scheme is further illustrated below with reference to specific embodiments, which are detailed below:
example 1:
in this example, a method of using MgO/SiO in a magnesium-containing mineral 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction comprises the following steps:
ball milling 1kg of serpentine ore for 1.5 hours to obtain granulesSerpentine mineral powder with a size of 200 meshes; then leaching by adopting sulfuric acid with the mass concentration of 50wt.%, wherein the solid-liquid ratio is 1 (g/mL), the reaction time is 2 hours, the temperature is 90 ℃, and the stirring speed is 500rpm; cross-flow leaching solid-liquid ratio 1:4 (g/mL) to reduce acidity of the solution to pH 3, performing solid-liquid separation, and collecting the magnesium sulfate leaching solution with a content of 20% P 507 Compared with 1:1, the extracted iron has acidity pH =3 and saponification rate of 100%; then carrying out two-phase separation, and adopting sodium hydroxide to precipitate iron to obtain ferric hydroxide; calcining at 500 ℃ to obtain iron oxide, and grinding into powder; concentrating the magnesium-containing leaching solution without iron at 90 ℃ for 2 hours, and then standing to obtain a magnesium sulfate heptahydrate crystallization product; then reacting the magnesium sulfate heptahydrate crystallization product with ammonia water at room temperature to obtain magnesium hydroxide precipitate and ammonium sulfate solution, filtering and separating to obtain Mg (OH) 2 Evaporating the filtrate to obtain ammonium sulfate; mg (OH) 2 Calcining at 1200 ℃ for 120 minutes to obtain an MgO product;
separating the solid and liquid to obtain the SiO-rich material 2 100g of the solid residue is washed, dried and ground into powder, or SiO 2 And the iron oxide mixture obtained above, and silicon is smelted in a vacuum reduction furnace. 200g of charcoal is added into a vacuum reduction furnace, the power of the vacuum furnace is 200MW, the smelting time is 3 hours, and the furnace temperature can be controlled within 1200 ℃, so that the molten ferrosilicon product reducing agent can be prepared and used for reducing MgO to prepare metal magnesium. In the molten ferrosilicon product, the mass content of silicon is 70-95% (w), and the mass content of iron is 1-30% (w).
In the vacuum furnace, residual gases CO and CO in the furnace are discharged 2 Under the vacuum condition, 500g of the calcined and dried MgO (or CaO) powder is sprayed into molten ferrosilicon, 10g of fluorite powder is added and stirred uniformly, the particle size of the MgO powder is 200 meshes, the reaction temperature is in the range of 1200 ℃, the generated magnesium is in a gas state under the negative pressure of about 10Pa, and the magnesium steam is condensed into solid magnesium through a cooling device.
Example 2:
this embodiment is substantially the same as embodiment 1, and is characterized in that:
in this example, a method of using a siliceous magnesium oreMgO/SiO in the substance 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction comprises the following steps:
the dolomite ore and the sepiolite ore are mixed and ball milled for 2 hours according to the proportion of 1:1 to obtain mixed mineral powder with the particle size of 200 meshes.
The other steps were the same as in example 1.
Example 2:
this embodiment is substantially the same as the previous embodiment, and is characterized in that:
in this example, a method of using MgO/SiO in a magnesium-containing mineral 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction comprises the following steps:
the forsterite is ball milled for 1 hour to obtain mineral powder with the particle size of 100 meshes. Then, hydrochloric acid with the mass concentration of 30wt.% is adopted for leaching, the solid-liquid ratio is 1 (g/mL), the reaction time is 2 hours, the temperature is 90 ℃, and the stirring speed is 500rpm. Reducing the acidity of the solution to 0.5-2 mol/L by using the cross-flow leaching solid-liquid ratio 1:4 (g/mL), carrying out solid-liquid separation, concentrating the obtained magnesium chloride leaching solution at 90 ℃ for 2 hours, and then standing to obtain a magnesium chloride crystal product. Then the magnesium chloride crystal product reacts with ammonia water at room temperature to obtain magnesium hydroxide precipitate and ammonium chloride solution, and Mg (OH) is obtained by filtration and separation 2 And evaporating the filtrate to obtain ammonium chloride.
The other steps are the same as in example 1.
The technical effects of the above embodiments:
Figure BDA0003526183030000091
the above embodiments of the invention relate to the carbothermic reduction of SiO from siliceous magnesium minerals or tailings 2 A method for reducing silicon and then reducing magnesium oxide into magnesium metal belongs to the fields of chemical industry, agriculture, metallurgy, metal materials, solid wastes and environment. Carbothermic reduction of SiO from siliceous magnesium minerals or tailings 2 A process for reducing silicon to magnesium metal and reducing magnesium oxide to magnesium metal, characterised in that an acid cross-flow leach is used to leach a magnesium-containing mineralOr tailings, filtering the separated liquid, extracting or precipitating to obtain ferric hydroxide, and calcining to obtain ferric oxide. Crystallizing the magnesium-containing leaching solution after iron removal to obtain a magnesium crystal; reacting the magnesium crystal with ammonia water to obtain Mg (OH) 2 And (NH) 4 ) 2 SO 4 Handle Mg (OH) 2 Calcining to prepare MgO; filtering the separated solid residue SiO 2 Or SiO 2 Reducing iron oxide and carbon to prepare molten ferrosilicon; and (3) reacting the molten ferrosilicon product with MgO and an additive or a cosolvent under a vacuum condition to obtain Mg steam, and condensing to obtain a magnesium metal product. The invention uses the minerals or tailings containing silicon and magnesium as raw materials to prepare the magnesium metal product, thereby reducing the resource waste and realizing the comprehensive utilization of the minerals or tailings; the invention uses the minerals or tailings containing silicon and magnesium as raw materials to prepare the magnesium metal product, the industrial cost is low, and the byproduct ammonium salt of the method is used as the raw material of the fertilizer, is used for agriculture and has good application prospect.
The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made according to the purpose of the invention, and any changes, modifications, substitutions, combinations or simplifications made based on the spirit and principle of the technical solution of the present invention shall be equivalent replacement, so long as the invention is in accordance with the purpose of the present invention, and the technical principle and the inventive concept of the present invention shall fall within the protection scope of the present invention.

Claims (10)

1. MgO/SiO utilizing silicon-magnesium containing mineral 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction is characterized by comprising the following steps of: pretreating silicon-magnesium-containing mineral or tailings into mineral powder, leaching the mineral powder with acid, and filtering to separate solid from liquid to obtain SiO 2 The solid residue and the magnesium-containing leaching solution are concentrated to obtain a magnesium salt crystallization product, the magnesium salt crystallization product is reacted with alkali to obtain magnesium hydroxide, and the magnesium hydroxide is calcined and converted to generate MgO powder;
separating iron in the magnesium-containing leaching solution by a precipitation or extraction process to obtain an iron hydroxide precipitate, calcining and converting to generate iron oxide, and ball-milling the iron oxide precipitate into iron oxide powder;
the filtered and separated SiO 2 Drying the solid residue, and ball-milling into SiO 2 Powder;
under the condition of adding the iron oxide powder, the SiO is added 2 Putting the powder and the carbon powder into a vacuum reduction furnace, and carrying out high-temperature reduction reaction to generate a molten ferrosilicon product;
under the in-situ condition, the MgO powder is sprayed into the molten ferrosilicon to be reduced to generate Mg steam, and a magnesium metal product is obtained through condensation.
2. The method of claim 1, wherein the magnesium silicate mineral is MgO/SiO 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction is characterized by comprising the following steps of: the magnesium-containing leaching solution contains at least one metal ion of iron ions, nickel ions and aluminum ions.
3. The method of claim 1, wherein the MgO/SiO ratio in the magnesium minerals containing silicon is utilized 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction is characterized by comprising the following steps of: the concentration process of the magnesium-containing leaching solution adopts cross-flow leaching or evaporation treatment.
4. The method of claim 1, wherein the MgO/SiO ratio in the magnesium minerals containing silicon is utilized 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction is characterized by comprising the following steps of: the base includes at least one of ammonia, a hydroxide, and a carbonate.
5. The method of claim 1, wherein the MgO/SiO ratio in the magnesium minerals containing silicon is utilized 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction is characterized by comprising the following steps of: the iron oxide comprises iron oxide obtained from waste iron oxidation treatment, waste iron acidolysis precipitation calcination treatment or directly industrial pure iron oxide.
6. The method of claim 1 using magnesium silicideMgO/SiO in minerals 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction is characterized by comprising the following steps of: the magnesium-containing mineral comprises at least one mineral selected from serpentine, magnesite, dolomite, sepiolite, talc, forsterite, bischofite and carnallite and tailings thereof.
7. The method of claim 1, wherein the magnesium silicate mineral is MgO/SiO 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction is characterized by comprising the following steps of: the acid is any one of inorganic acid or mixed acid of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and carbonic acid, or the acid is any one of organic acid or mixed acid of oxalic acid, tartaric acid, acetic acid, boric acid, citric acid and formic acid; or the acid is a mixed acid of the inorganic acid and the organic acid.
8. The method of claim 1, wherein the MgO/SiO ratio in the magnesium minerals containing silicon is utilized 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction is characterized by comprising the following steps of: adding the iron oxide to the SiO 2 Putting the powder and the carbon powder into a vacuum reduction furnace to carry out high-temperature reduction reaction to generate a molten ferrosilicon product; the grain diameter of the mixed powder is 10-200 meshes, and the mixed powder comprises the following components in percentage by weight: siO 2 2 Powder, or SiO 2 The mixture of the powder and the ferric oxide is 2-5kg; 0.3-1kg of charcoal, or 0-1 kg of anthracite or bituminous coal, or 0.1-0.9 kg of petroleum coke, or 1-4 kg of sawdust; the power of the vacuum furnace is 1-2000MW, the smelting time is 1-40 hours, and the furnace temperature is controlled within the range of 1000-2000 ℃ to obtain a molten ferrosilicon product; the silicon content of the molten ferrosilicon product is 70-95% (w) by mass, and the iron content of the molten ferrosilicon product is 1-30% (w) by mass.
9. The method of claim 1, wherein the MgO/SiO ratio in the magnesium minerals containing silicon is utilized 2 A method for extracting magnesium metal through carbon in-situ high-temperature reduction reaction is characterized in that under the in-situ condition, mgO powder is sprayed into molten ferrosilicon, and the reduction reaction conditions of the molten ferrosilicon product and MgO comprise: mgO powder with particle size of 10-200 meshesThe temperature is 700-1800 ℃, and the proportion of the raw materials for vacuum smelting of magnesium is as follows according to the mass proportion under the condition of negative pressure of 1-20 Pa:
CaO + MgO (or MgO), reducing agent and additive (or fluxing agent) in a mass ratio of 90-110;
the reducing agent is silicon powder, ferrosilicon powder or a mixture of silicon and iron powder.
10. The method according to claim 9, wherein the MgO/SiO ratio in the magnesium minerals containing silicon is utilized 2 The method for extracting the metal magnesium through the carbon in-situ high-temperature reduction reaction is characterized by comprising the following steps of: the additive and the fluxing agent can be used singly or in a mixture; the additive adopts fluorite powder and MgF 2 At least one of NaF and inorganic fluoride; the fluxing agent adopts Al 2 O 3 And CaO.
CN202210193948.8A 2022-03-01 2022-03-01 Utilizing MgO/SiO in silicon-magnesium-containing minerals 2 Method for extracting magnesium metal through carbon in-situ high-temperature reduction reaction Pending CN115161478A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210193948.8A CN115161478A (en) 2022-03-01 2022-03-01 Utilizing MgO/SiO in silicon-magnesium-containing minerals 2 Method for extracting magnesium metal through carbon in-situ high-temperature reduction reaction

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210193948.8A CN115161478A (en) 2022-03-01 2022-03-01 Utilizing MgO/SiO in silicon-magnesium-containing minerals 2 Method for extracting magnesium metal through carbon in-situ high-temperature reduction reaction

Publications (1)

Publication Number Publication Date
CN115161478A true CN115161478A (en) 2022-10-11

Family

ID=83484334

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210193948.8A Pending CN115161478A (en) 2022-03-01 2022-03-01 Utilizing MgO/SiO in silicon-magnesium-containing minerals 2 Method for extracting magnesium metal through carbon in-situ high-temperature reduction reaction

Country Status (1)

Country Link
CN (1) CN115161478A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1618999A (en) * 2004-12-10 2005-05-25 青海中信国安科技发展有限公司 Method of producing metal magnesium by bischofite drying calicing to make magnesium oxide to vacuum thermo reduction
CN101235440A (en) * 2008-03-14 2008-08-06 大悟华龙吕王石材有限公司 Method of comprehensively utilizing serpentine
CN103710550A (en) * 2013-12-27 2014-04-09 兰新哲 Method for poly-generation and large-scale coupling production based on semi coke and magnesium
US20170355609A1 (en) * 2014-11-18 2017-12-14 Alliance Magnésium Process to produce magnesium compounds, and various by-products using sulfuric acid in a hcl recovery loop

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1618999A (en) * 2004-12-10 2005-05-25 青海中信国安科技发展有限公司 Method of producing metal magnesium by bischofite drying calicing to make magnesium oxide to vacuum thermo reduction
CN101235440A (en) * 2008-03-14 2008-08-06 大悟华龙吕王石材有限公司 Method of comprehensively utilizing serpentine
CN103710550A (en) * 2013-12-27 2014-04-09 兰新哲 Method for poly-generation and large-scale coupling production based on semi coke and magnesium
US20170355609A1 (en) * 2014-11-18 2017-12-14 Alliance Magnésium Process to produce magnesium compounds, and various by-products using sulfuric acid in a hcl recovery loop

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
张子佳等: "硅铁的冶炼技术与应用进展", 《现代矿业》, no. 4, pages 102 - 105 *

Similar Documents

Publication Publication Date Title
CN100584764C (en) Method for reclaiming ferric oxide from coal ash and coal gangue
CN103086405B (en) Clean production method of battery level lithium carbonate
CN103130279B (en) A kind of method of chlorination production high purity vanadic anhydride
CN101348280B (en) Method for preparing electronic grade non-selenium manganomanganic oxide from dialogite
CN103101935B (en) Method for preparing lithium carbonate from coal ash
CN102586805B (en) Preparation method of metal magnesium by magnesium-containing mineral and equipment adopted by preparation method
CN103276218B (en) Method for recycling vanadium from vanadium-containing electrolysis aluminum slag ash
CN104528834B (en) Artificial rutile mether liquor recycling novel method
CN101885496B (en) Process for extracting lithium from lithionite by fluorine chemistry
CN113292057B (en) Recovery method of waste lithium iron phosphate battery
CN115259230B (en) Impurity removal method for producing trimanganese tetroxide for soft magnetism from electrolytic manganese anode mud by utilizing molten acid leaching
CN110963515B (en) Method for recovering alumina from fly ash
CN115011799B (en) Method for producing soft magnetic trimanganese tetroxide by using electrolytic manganese anode slime
WO2014047764A1 (en) Method for producing high-purity nanometer zinc oxide from steel plant smoke and dust by ammonia decarburization
CN113582213A (en) Method for comprehensively utilizing fly ash
CN114920245A (en) Mineralized substance for carbon dioxide sequestration and application thereof
CN115074540A (en) Comprehensive recovery method for valuable components of waste power battery
CN109264748B (en) Method for preparing lithium carbonate from crude lithium phosphate
CN102417995A (en) Process for extracting lithium from lithium pyroxene concentrate by using fluorine chemistry
CN115448273B (en) Method for preparing lithium dihydrogen phosphate by taking lepidolite as raw material
CN102242282B (en) Alkaline reduction smelting method for vanadium polymetallic ore
CN115161478A (en) Utilizing MgO/SiO in silicon-magnesium-containing minerals 2 Method for extracting magnesium metal through carbon in-situ high-temperature reduction reaction
CN115505740A (en) Resource method for treating red mud by adopting nitrate wastewater
CN108063295A (en) The method that lithium is extracted in the clinker generated from pyrogenic process recycling lithium battery
CN112723311A (en) Method for comprehensively utilizing artificial rutile mother liquor by utilizing iron ore

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination