WO2016131206A1 - 基于镁合金废料生产国标镁合金锭的方法 - Google Patents

基于镁合金废料生产国标镁合金锭的方法 Download PDF

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Publication number
WO2016131206A1
WO2016131206A1 PCT/CN2015/074840 CN2015074840W WO2016131206A1 WO 2016131206 A1 WO2016131206 A1 WO 2016131206A1 CN 2015074840 W CN2015074840 W CN 2015074840W WO 2016131206 A1 WO2016131206 A1 WO 2016131206A1
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Prior art keywords
magnesium alloy
producing
scrap
magnesium
ingot based
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PCT/CN2015/074840
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English (en)
French (fr)
Inventor
谭何易
唐伦圆
Original Assignee
谭何易
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Application filed by 谭何易 filed Critical 谭何易
Priority to CN201580075907.7A priority Critical patent/CN107429318A/zh
Publication of WO2016131206A1 publication Critical patent/WO2016131206A1/zh
Priority to US15/677,014 priority patent/US20180023164A1/en

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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
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/005—Preliminary treatment of scrap
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
    • B08B3/02—Cleaning by the force of jets or sprays
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
    • B08B3/04—Cleaning involving contact with liquid
    • B08B3/06—Cleaning involving contact with liquid using perforated drums in which the article or material is placed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D7/00—Casting ingots, e.g. from ferrous metals
    • B22D7/005—Casting ingots, e.g. from ferrous metals from non-ferrous metals
    • 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
    • C22B7/001—Dry processes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/02—Making non-ferrous alloys by melting
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C23/00—Alloys based on magnesium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C23/00—Alloys based on magnesium
    • C22C23/02—Alloys based on magnesium with aluminium as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/12—Light metals
    • 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 relates to a method for recycling and recycling magnesium alloy waste, in particular to a method for producing a national standard magnesium alloy ingot by using a scrap magnesium alloy product as a raw material, and belongs to the technical field of chemical industry.
  • magnesium alloys have low density, good rigidity, corrosion resistance, impact resistance, friction resistance, no deformation, non-toxicity, non-magnetic properties, good thermal conductivity, excellent damping damping and electromagnetic shielding performance, and easy processing. And easy to recycle; and the same volume of magnesium alloy is 36% lighter than aluminum alloy, 73% lighter than zinc alloy, magnesium alloy is becoming the material of choice for modern automotive electronics and other industries, widely used in aviation, aerospace, electronics, automotive In the fields of computers, telecommunications, etc., it is known as the green engineering material of the 21st century.
  • the auto parts made of magnesium alloy can reduce the vehicle's own weight, improve the fuel utilization rate and reduce the environmental pollution.
  • the use of magnesium alloy to manufacture aircraft, missiles, spacecraft, satellites, light weapons and other important weapons and components means the weapon's range, hit rate and The maneuverability of the aircraft is improved, and the launch cost of the spacecraft is reduced.
  • the magnesium alloy is used to manufacture the outer casing of digital products such as mobile phones, notebook computers and digital cameras, and has the advantages of high strength, beautiful appearance and electromagnetic shielding. Due to the expansion of magnesium alloys in these fields, since the 1990s, the amount of magnesium has been maintained at an annual rate of more than 20% for 10 consecutive years. In 1990, magnesium was produced at 260,000 tons, and in 2002, magnesium was produced 46.
  • magnesium alloy waste has the advantages of high regeneration rate and low energy consumption, its regeneration rate can reach more than 95%, and the energy consumption for recycling and regeneration is only about 5% of the energy consumption of raw magnesium production. Therefore, the reasonable recycling of magnesium alloy scrap directly affects the rationality and sustainability of the development of the magnesium and magnesium alloy industry.
  • the classification and classification of magnesium alloy waste helps to enhance the recycling of magnesium alloy waste, thereby saving resources and reducing The purpose of production costs.
  • the magnesium alloy classification and classification international standard proposal divides the magnesium alloy waste into 8 grades, see Table a.
  • the prior art technology for recovering magnesium alloy scrap generally refers to the recovery of the first to fifth grade magnesium alloy scraps.
  • the flux refining method and/or the fluxless refining method are used to remove the magnesium alloy scrap and then die-cast into a new magnesium alloy. Ingot (Wang Xiaoming, etc., research and development of high-risk magnesium alloy scrap recycling technology and equipment for die casting [J], Special Casting and Nonferrous Alloys, 2011, 31(12): 1127-1131).
  • scrapped magnesium alloy products are an important source of magnesium alloy scrap, including scrapped automobile wheels, steering wheel, engine cylinder head, aircraft fuselage, skin, computer and camera casing, etc., totaling 200,000 tons. /year or more.
  • the domestic treatment method is as a consumable and non-standard magnesium.
  • Raw materials for alloy ingots such as fireworks coloring agents, desulfurizers and non-standard magnesium alloy ingots, such methods are used to downgrade magnesium alloy scrap. Making it non-renewable not only reduces the value of the product, but also greatly wastes the magnesium resources, thereby limiting its efficient and high-value recycling.
  • the national standard magnesium alloy ingot is an important raw material for the preparation of magnesium alloy castings.
  • the commonly used national standard magnesium alloy ingot preparation process is based on pure magnesium and the required alloying elements, and the components obtained by melting, refining and alloying meet the requirements of the national standard.
  • the magnesium alloy solution is then poured into ingots.
  • the process requires strict requirements on the components of pure magnesium and alloy raw materials required, and the expensive magnesium ingots and alloy raw materials satisfying the requirements are expensive, and the production cost of preparing the national standard magnesium alloy ingot is greatly improved.
  • scrap magnesium alloy castings Due to the high quality of scrapped magnesium alloy castings, the main factors limiting their utilization are oil stains, mud scales and oxide layers on the surface of waste materials. If a reasonable pretreatment process can be used to completely remove impurities on the surface of waste materials, theoretically, scrap magnesium alloy castings are The composition can meet the requirements of the raw material for preparing the national standard magnesium alloy ingot. The energy required to remelt the national standard magnesium alloy ingot by magnesium alloy scrap is only about 3KWh/kg, which is more than one order of magnitude lower than the production of a national standard magnesium alloy ingot. .
  • Chinese invention patent CN 101736160 B discloses a method for recovering low-grade scrap of magnesium alloy, which is prepared by mechanical cutting, repeated pickling, water washing, electric resistance furnace melting, refining and casting into ingots to prepare magnesium alloy low-grade scrap ingots, but its chemical composition Only close to the compositional index of the magnesium alloy ingot, the mechanical properties are only close to the amount of the magnesium alloy ingot, which limits its application range.
  • the Chinese invention patent application CN 101338378 A discloses a process for remelting and casting a magnesium alloy ingot to obtain a magnesium alloy ingot. The method uses a steel gun of 3 to 5 mm to polish the scrap material for 30 to 40 minutes, resulting in irregular shape scrap grinding.
  • the object of the present invention is to provide a method for producing and producing a national standard magnesium alloy ingot,
  • the method can directly use the scrap magnesium alloy product as a raw material for producing the national standard magnesium alloy ingot, without adding expensive high-purity magnesium, and only adding a small amount of other alloy raw materials.
  • a method for producing a national standard magnesium alloy ingot based on total magnesium alloy scrap comprising the following steps:
  • Step a sorting, removing, cleaning and drying the magnesium alloy waste, and the cleaning comprises high-pressure cleaning, pickling and water washing in sequence;
  • Step b preheating, feeding melting, refining, impurity removing and alloying the magnesium alloy scrap obtained in step a to obtain a magnesium alloy liquid;
  • step c the magnesium alloy liquid obtained in the step b is subjected to ingot casting to obtain a national standard magnesium alloy ingot.
  • the above magnesium alloy scrap is selected from the scrap magnesium alloy casting scrap in the international standard for classification and classification of magnesium and magnesium alloy waste.
  • step b or step c is carried out under hypoxic or anaerobic conditions, preferably in an inert atmosphere, preferably N 2 or SO 2 .
  • magnesium alloy scraps are usually hollow structures with low bulk density, so steps The magnesium alloy scrap in a is also cut before being sorted and removed.
  • the pressure of the high pressure washing in the step a is 5 to 20 MPa, preferably 10 to 15 MPa.
  • step a comprises cutting, removing impurities, high pressure cleaning, pickling, washing and drying the magnesium alloy scrap; wherein, the following steps can be divided into:
  • Step a1 cutting the bulk magnesium alloy waste into a plurality of small-sized magnesium alloy scraps to separate the magnesium alloy material containing the screw and the rubber, and satisfy the requirements of the raw material size of the subsequent processing equipment;
  • Step a2 sorting and removing the cut magnesium alloy scrap to remove impurities that cannot be separated from the magnesium alloy scrap;
  • Step a3 performing high pressure cleaning on the magnesium alloy scrap after sorting and removing impurities to remove dust, oil, mud or loose oxide layer on the surface of the magnesium alloy scrap;
  • Step a4 pickling the magnesium alloy scrap after high pressure cleaning
  • Step a5 washing the pickled magnesium alloy scrap with water
  • Step a6 Drying the washed magnesium alloy scrap.
  • step a further comprises the step a7 of: re-sorting the dried magnesium alloy scrap to obtain clean waste; wherein, the clean waste defines: magnesium alloy waste having a harmful element content within the national standard, wherein the harmful element is Refers to elements that significantly reduce certain properties of magnesium alloys (including corrosion resistance, mechanical properties, etc.) even in small amounts, Such as Si, Cu, Ni, Fe, and the like.
  • step a1 the specific operation of step a1 is: cutting the magnesium alloy scrap by using a metal crusher, wherein the dimension of the magnesium alloy scrap after cutting is not more than 300 mm, preferably 50-300 mm, and most preferably 100 mm. It is determined according to the size and equipment of the magnesium alloy to be treated.
  • step a2 sorting the unseparable scrap containing scraps of screws, rubber and plastic, the scrap containing organic coating on the surface, and the non-magnesium material from the magnesium alloy scrap obtained in step a1, in other words, The screws, rubber, plastics, etc. contained in the magnesium alloy scrap are separated from the magnesium alloy scrap, and the remaining magnesium alloy scrap is reserved.
  • step a3 the specific operation of step a3 is: placing the magnesium alloy waste obtained in step a2 in a solid material device, and performing high pressure cleaning on the magnesium alloy scrap in the solid material device using a high pressure cleaner;
  • the high-pressure cleaning solid material is preferably realized by a mesh (hollow) roller, or other prior art solid material method, depending on the production conditions of the implementation site of the present invention; wherein the mesh roller has an aperture Less than 50mm, under the premise of ensuring that the strength of the drum can withstand the impact pressure of high-pressure water, the number of meshes per unit area of the drum is maximized, and the specific number can be adjusted according to the conditions of the drum material, the pressure of high-pressure cleaning or the aperture of the mesh, so that The aqueous solution produced by high-pressure cleaning can be discharged in time to prevent the cleaning liquid from directly impacting on the waste and affecting the cleaning effect.
  • a mesh (hollow) roller or other prior art solid material method, depending on the production conditions of the implementation site of the present invention
  • the solid-state device is an electrically driven mesh drum, and the mesh drum is rotated by electric driving, so that the magnesium alloy scrap is randomly inverted with the rotation of the mesh drum.
  • the impact force of the water is greater than the adhesion of the impurities to the surface of the magnesium alloy scrap, so the strong water pressure generates sufficient foam to Generally, the impurities are peeled off and washed away, so the high-pressure cleaning is a high-pressure cleaning; however, when the surface of the magnesium alloy waste to be treated has oil or a release agent during the cleaning process, a thick layer of oil and mud is usually adhered to the oily surface. The mixed impurity layer is formed.
  • the high pressure water can wash away the mixed impurity layer due to its pressure, since the water and the oil are incompatible with each other, it is impossible to completely remove the oil stain or the release agent attached to the surface of the magnesium alloy waste, and further need to be further removed.
  • the cleaning agent capable of removing oil or mold release agent is added, so the inventor divides the high pressure cleaning into two high pressure cleanings, one high pressure cleaning and the other high pressure cleaning.
  • the high pressure water of one high pressure cleaning can remove the impurities on the surface of the magnesium alloy waste.
  • the high-pressure water added with the cleaning agent in the high-pressure cleaning can easily remove the oil stain or mold release agent on the surface and further remove it. Loose dirt and oxide layers.
  • the cleaning agent is a degreaser
  • the type and concentration of the degreaser may be determined according to the type and amount of oil stain on the surface of the waste, preferably a water-based metal degreaser, preferably an acidic water-based metal.
  • the oil agent may also be other degreasers such as metal emulsifiers or biodegradable agents in the prior art.
  • the cleaning solution for high-pressure cleaning is water and/or a cleaning agent, and the pH of the cleaning solution is 5-7.
  • the cleaning liquid for a high-pressure cleaning is water, and the cleaning time is 10 to 30 minutes;
  • the cleaning liquid for high-pressure cleaning is an aqueous solution to which a cleaning agent is added, the temperature of the cleaning liquid is 40 to 70 ° C, the cleaning time is 5 to 10 minutes, and the high-pressure cleaning is performed.
  • the specific cleaning time or cleaning temperature can be determined based on the severity of the oil.
  • step a4 the specific operation of step a4 is: the magnesium alloy scrap obtained in step a3 is placed in a pickling tank for pickling to remove the oxide layer on the surface of the magnesium alloy scrap.
  • the pickling time is 30 to 90 s
  • the pickling acid washing liquid has a pH of 1 to 3
  • the pickling liquid is a mixture of one or more of hydrochloric acid, nitric acid, sulfuric acid or oxalic acid solution, specifically according to the magnesium alloy waste. The degree of oxidation of the surface is determined.
  • the acid washing liquid can be repeatedly used repeatedly. To ensure the pH range of the acid washing liquid, each time the appropriate acid concentration is added according to the pH value of the acid washing liquid to a pH value of 1 to 3, when the concentration of Mg 2+ in the solution is reached . When it is more than 2.0mol/L, the acid pickling liquid is replaced; the waste acid generated by pickling is recovered by neutralization, filtration, evaporation crystallization and drying steps, and the treatment process is: neutralization of the waste acid by using MgO or MgCO 3 The treatment has a pH of about 7, and then filtered, and the filtrate is dehydrated to obtain a dry magnesium salt; the obtained dry magnesium salt is relatively high in purity and is mostly used for preparing a magnesium fertilizer raw material.
  • the filter uses a filter press.
  • the removal of moisture from the filtrate is achieved by evaporation, concentration, filtration, drying, or other prior art methods of removing moisture, such as vacuum drying techniques, depending on the conditions of the site in which the invention is practiced.
  • the filtrate is evaporated, concentrated, filtered and dried by a crystallizer and its associated filter and dryer.
  • the specific operation of the step a5 is: removing the acid liquid and impurities remaining on the surface of the magnesium alloy scrap obtained in the step a4 with water, preferably by a rinsing method or a spraying method, or other water washing methods of the prior art, which can be regarded as the present invention.
  • removing the acid liquid and impurities remaining on the surface of the magnesium alloy scrap obtained in the step a4 with water preferably by a rinsing method or a spraying method, or other water washing methods of the prior art, which can be regarded as the present invention.
  • the specific operation of the step a6 is: removing the residual moisture on the surface of the magnesium alloy waste obtained in the step a5, preferably by the wind cutting method or the drying method, or other water washing methods of the prior art, which can be regarded as the implementation site of the present invention.
  • the pretreatment of the magnesium alloy scrap is completed at this time; the definition of the wind cut method: the wind cut is simply using the impact energy of the high pressure wind to remove the water droplets from the waste surface, reducing the time and pressure of the hot air drying, and reducing the waste. Oxidation, usually without hot air.
  • the specific operation of the step a7 is: sorting the unclean waste and the non-magnesium material in the magnesium alloy scrap obtained in the step a6 to obtain clean waste.
  • the step b comprises preheating, melting, detecting harmful elements, refining, alloying, slag and temperature-controlled standing of the magnesium alloy scrap obtained in the step a, wherein the step can be divided into the following steps:
  • Step b1 preheating the magnesium alloy scrap obtained in the step a to remove the water vapor to prevent the water vapor from causing an explosion, and at the same time Reduce gas inclusions caused by moisture;
  • Step b2 heating the magnesium alloy scrap obtained in step b1 to melt;
  • Step b3 detecting the specific content of each harmful element in the magnesium alloy liquid obtained in step b2, and selecting whether to prepare the national standard magnesium alloy ingot according to the specific content thereof;
  • Step b4 The magnesium alloy liquid used for preparing the GB magnesium alloy ingot obtained by the step b3 is refined;
  • Step b5 alloying the magnesium alloy liquid obtained in step b4;
  • Step b6 detecting the specific content of each metal element in the magnesium alloy liquid obtained in step b5;
  • Step b7 analyzing whether the specific content of each metal element except the elemental iron detected in step b6 is up to standard: if the standard is reached, proceed to the next step, if not, repeat step b5 and step b6 to reach the standard;
  • Step b8 The slag magnesium alloy liquid obtained by the step b7 is subjected to slag removal;
  • Step b9 controlling the temperature and standing of the magnesium alloy liquid obtained in step b8;
  • Step b10 Detecting and analyzing whether the specific content of elemental iron of the magnesium alloy liquid obtained in step b9 is up to standard, and after proceeding to the standard, it may proceed to step c. It is worth mentioning that in order to reduce the cost and save time, it is also possible to re-refin the magnesium alloy liquid alloying process to obtain a higher purity magnesium alloy liquid.
  • step b6 uses the cast magnesium alloy ingot GB/T 19078-2003 as a standard to determine whether each metal element in the magnesium alloy liquid meets the standard.
  • step b1 the specific operation of step b1 is: putting clean waste into the oven, and discharging the water vapor generated by the evaporation through the air suction device.
  • the preheating temperature of the step b1 is 120 to 150 °C.
  • step b1 the warm-up time of step b1 is 5 to 20 minutes.
  • step b2 the specific operation of step b2 is: adding the preheated magnesium alloy waste into the smelting furnace in stages, and gradually adding a melting agent (60-100 kg/ton of melting agent) during the feeding process for covering the fire extinguishing.
  • a melting agent 60-100 kg/ton of melting agent
  • the furnace temperature in the melting furnace is 850-950 °C.
  • the melting agent is a conventional alloy melting agent in the prior art, such as No. 2 flux, which is preferably selected according to the magnesium alloy ingot which is prepared in actual production, and is not limited herein as the preparation method disclosed in the present invention.
  • the magnesium alloy scrap may be added to the melting furnace in stages to melt, and the amount of the first added magnesium alloy scrap is 1/3 of the total capacity of the melting furnace. 1/4, after that, the amount of magnesium alloy scrap added is 1/4 to 1/5 of the total capacity of the smelting furnace until the smelting furnace is filled.
  • the total capacity of the smelting furnace is selected according to the demand of the national standard magnesium alloy ingot, preferably 1t. 2t or 3t; after each feeding, a layer of melting agent should be evenly spread on the surface of the magnesium alloy scrap to avoid the high temperature causing the magnesium alloy to burn.
  • step b4 the process proceeds selectively to step b4 to obtain different types of alloyed products; that is, the content of each harmful element detected in step b3 is consistent.
  • the national standard requires the preparation of the national standard magnesium alloy ingot, otherwise it can be used to prepare the non-standard magnesium alloy ingot; the method provided by the invention can directly prepare the AZ91D national standard magnesium alloy ingot by using the magnesium alloy waste; in addition, if other grades of the national standard magnesium are to be prepared Alloy ingots, such as AM50A/AM60B, can be diluted by adding pure magnesium to achieve the content of the main elements, the amount of pure magnesium can be determined according to the specific grade.
  • step b4 the specific operation of step b4 is: feeding the molten magnesium alloy scrap into the melting furnace, uniformly adding the refining agent, stirring, and using the refining agent to cover the fire extinguishing during the stirring process.
  • the specific operation of the step b5 is: sampling and analyzing the magnesium alloy liquid obtained in the step b4, determining the addition amount of each alloy element according to the analysis result, and then adding the magnesium alloy liquid obtained in the step b4 to the alloy raw material, uniformly in the melting process of the alloy raw material.
  • the added refining agent is stirred and stirred during the stirring process, and the alloying and re-refining are simultaneously performed.
  • the refining agent is uniformly added, preferably a small amount of refining agent is added in a small amount, the total addition amount is 15 to 25 kg/t; the refining time is 15 to 30 min; the stirring is mechanical stirring and/or gas injection; refining Stir in the process.
  • step b4 the refining temperature of step b4 is 710 to 730 °C.
  • the refining temperature of the step b5 is 720 to 740 °C.
  • the refining agent used in the refining process is all refining agents used in alloy refining in the prior art, for example, a composite flux of No. 2 flux and fluorite powder, and the ratio of fluorite powder is between 10% and 25%, according to
  • the preferred selection of the magnesium alloy ingots to be prepared in actual production is not limited herein as the preparation method disclosed in the present invention.
  • each metal element when alloying in step b5 is as follows:
  • Mg one or more magnesium ingots
  • Al one or more aluminum ingots
  • Zn one or more zinc ingots
  • Mn one of a high-purity Al-Mn alloy, a metal manganese powder having a purity greater than 99.8%, or an anhydrous manganese chloride having a purity greater than 99.8%;
  • the Be element is usually added in the late stage of refining because it is easily oxidized and volatilized, in order to reduce its loss.
  • the addition of the alloy is Mn, Al, and Zn, Mg (determining whether or not to be added according to actual conditions), and finally adding Be.
  • the order of addition of the above five alloying elements is only the order of addition when it is necessary to add, and Non-fixed addition order; if it is not necessary to add Mg, the order of addition of alloying elements is Mn, Al and Zn, and finally Be.
  • step b8 the specific operation of step b8 is: using a slag bag to slag the alloyed/re-refined magnesium alloy liquid, and then blowing with dry nitrogen to make the magnesium slag sinking into the bottom of the smelting furnace be blown again.
  • the magnesium slag falls into the slag bucket. Due to the high density of the magnesium slag, the magnesium liquid in the slag bucket is gradually squeezed out, thereby achieving the purpose of slag removal.
  • step b9 the specific operation of step b9 is: the magnesium alloy liquid obtained in step b8 is allowed to stand, and the temperature is controlled at the same time, that is, the magnesium alloy liquid obtained in step b8 is cooled and then heated, and the cooling method in the prior art can be used, for example, The furnace is sprayed with cold air or added with an appropriate amount of national standard magnesium alloy ingot to assist in cooling. When the temperature drops to 640 ⁇ 5°C, the temperature is immediately raised to 660-670 °C to remove the impurity iron in the magnesium alloy solution.
  • the time required for the step b9 is the standing time or the temperature control time, which is determined after the time arrives.
  • step b6 or step b10 is performed by atomic emission spectrometry, or other alloy element detecting methods and instruments in the prior art, and will not be described herein.
  • the standard magnesium alloy liquid detected in step b10 is reserved or transferred to a holding furnace, and is protected by a sulfur powder or a mixed gas of SO 2 and N 2 , and the magnesium alloy liquid which is not completely transferred is treated with a covering agent. Protection; facilitate the magnesium alloy liquid to be further allowed to stand for subsequent ingot casting.
  • the holding temperature is 640 to 670 °C.
  • the magnesium alloy solution is transferred using a pipetting pump or a pipetting bag; wherein the pipetting pump and the pipette or pipetting bag are preheated prior to use.
  • step c comprises the following steps:
  • Step c1 preheating the ingot mold and uniformly coating a layer of the release coating on the inner surface of the ingot mold;
  • Step c2 preheating the casting pump and the casting pipe
  • Step c3 Connect the casting pump and the pipe, start the casting machine, and start casting.
  • the cast magnesium alloy ingot is uniformly cooled to avoid segregation.
  • the preheating temperature is 150 to 220 ° C; and the pouring temperature is 660 to 670 ° C.
  • step c further comprises the step c4 of: post-treating the magnesium alloy ingot obtained in step c3 by polishing, coding or coding, and packaging.
  • the invention can directly use magnesium alloy scrap as raw material, and is particularly suitable for all of the scrap magnesium alloy products as raw materials, and the national standard magnesium alloy ingot is produced, the use value is high, and the production cost is greatly reduced;
  • the pretreatment process of the invention has excellent cleaning and impurity removing effect, and the smelting method is advanced and reasonable, and the combination of the two effectively realizes that all the magnesium alloy scraps are used as raw materials to produce the national standard magnesium alloy ingot, and no expensive high-purity magnesium is needed;
  • the acid solution in the pretreatment process can be recycled, and the waste acid produced can also prepare high-purity magnesium salt as raw material of magnesium chemical fertilizer, realize zero discharge of pickling wastewater, and be economical and environmentally friendly;
  • the magnesium alloy scrap itself contains a certain amount of alloying elements, and only a small amount of alloying elements can be added to obtain a qualified magnesium alloy liquid during alloying, and the alloying elements to be added are greatly reduced, thereby further reducing the production cost;
  • the magnesium slag obtained after refining can be harmlessly treated by the inventor's preliminary research (patent application number: PCT/CN2014/075237) to obtain high-purity magnesium oxide, which can minimize environmental pollution, and three wastes. Efficient use of the cycle to meet the requirements of energy saving and emission reduction, thus providing excellent economic and environmental benefits;
  • the energy consumption is relatively low, and the energy consumption of remelting the magnesium alloy ingot by magnesium alloy scrap can be reduced to less than 10% of the production of magnesium alloy ingots;
  • each of the reagents used in the following examples are commercially available, and are used according to the specification or their corresponding standards; in addition, the melting agents used in the following examples are all produced by Binhai County Hengwang Light Metal Flux Co., Ltd.
  • the melting agent and refining agent are refining agents produced by Binhai County Hengwang Light Metal Flux Co., Ltd.
  • AZ91D magnesium alloy ingot is produced from the scrap magnesium alloy product of batch number 2013-10-05-A imported from Sweden by Hunan Srimo Technology Co., Ltd., the batch of magnesium alloy waste is 5000t in total, and the surface thereof contains oil stain. And the proportion of scrap of the release agent is about 10% of the total amount, and the production steps are as follows:
  • Sorting and removing impurities sorting out the inseparable scrap rubber and plastic scrap, the organic coated scrap and the non-magnesium material from the cut magnesium alloy scrap, leaving the magnesium alloy scrap spare;
  • the 895-1 type heavy-duty hot water high-pressure cleaner is used to perform high-pressure cleaning on the magnesium alloy scrap after sorting and removing the impurities, the cleaning liquid is water, the pressure is 10 MPa, and the cleaning time is 20 min;
  • the high-pressure cleaning of the magnesium alloy scrap is subjected to high-pressure cleaning again by using the 895-1 heavy-duty hot water high-pressure cleaner.
  • the cleaning liquid is an aqueous solution containing an acidic water-based metal degreaser, according to the formula. Prepared water soluble The pH of the liquid is 5.5, the temperature of the aqueous solution is 55 ° C, the pressure is 10 MPa, and the cleaning time is 10 min;
  • the preheated magnesium alloy waste is added to the high-temperature melting furnace in batches, and 8% of the melting agent is gradually sprinkled during the feeding process for covering the fire extinguishing; the furnace temperature is 850-950 ° C;
  • Refining uniformly disperse the refining agent in batches, stir by mechanical stirring and gas spraying, and use a refining agent to cover the fire extinguishing during the stirring process; the refining time is 20 min, and the refining temperature is 720 ° C;
  • the weight of the magnesium alloy solution at the time of sampling is 2950Kg.
  • each alloy raw material is sequentially added, and 2% is uniformly added during melting of the alloy raw material.
  • the refining agent is stirred by mechanical stirring and gas spraying, and the refining agent is used for covering and extinguishing during the stirring process; the alloying/refining time is 15 min, and the temperature is 740 ° C;
  • Ingot mold pretreatment preheating the ingot mold to 180 ° C, and uniformly coating a layer of release coating on the inner surface of the ingot mold;
  • Post-treatment The magnesium alloy ingot obtained after casting is subjected to post-treatment such as polishing, coding and packing.
  • the components of the magnesium alloy ingot produced in the present embodiment completely conform to the national standard; the chloride ion content is 0.0010%, and the flux slag is less.
  • the number of harmful elements reaching the standard of the 1# sample accounts for more than 98% of the total heat, and slightly exceeds the standard of 2%, and there is no serious excess of the heat.
  • the weight of the magnesium alloy solution at the time of sampling is 2550Kg.
  • the content of harmful element Si is 0.046%, which is in line with national standards, and can be directly subjected to subsequent alloying/refining operations.
  • the components of the magnesium alloy ingot produced in the present embodiment completely conform to the national standard; the chloride ion content is 0.0010%, and the flux slag is less.
  • the number of harmful elements reaching the standard of the 2# sample accounts for more than 98% of the total heat generation, and slightly exceeds the standard of 2%, and there is no severely exceeded standard heat.
  • the target magnesium alloy ingot is AM60B; since the target magnesium alloy ingot is different, the alloying elements to be added are also different.
  • the magnesium alloy solution weighs about 1650Kg when sampling.
  • the components of the magnesium alloy ingot produced in the present embodiment completely conform to the national standard; the chloride ion content is 0.0010%, and the flux slag is less.
  • the number of harmful elements reaching the standard of the 3# sample accounts for more than 98% of the total heat, and slightly exceeds the standard of 2%, and there is no severely exceeded standard.
  • Table a shows the results of spectral analysis of magnesium alloy liquid obtained without pretreatment
  • Example 2 The same AZ91D magnesium alloy ingot as in Example 1 was prepared by a conventional process, and the amount of each alloy raw material to be alloyed was as follows:
  • the same magnesium alloy ingot prepared by the same process as in Example 1 requires not only pure magnesium as a raw material, but also the amount of each alloying element to be added is significantly higher than the added amount of the present invention, so the present invention provides
  • the magnesium alloy ingot production method requires lower raw materials, lower cost, and is beneficial to material recycling, energy saving and environmental protection.
  • the method for producing the national standard magnesium alloy ingot provided by the invention directly uses the magnesium alloy scrap as the raw material, and is particularly suitable for the production of the national standard magnesium alloy ingot by using all the scrap magnesium alloy products as raw materials, without adding expensive price.
  • High-purity magnesium the number of harmful elements up to the standard accounted for more than 98% of the total heat, slightly exceeded the standard of 2%, no serious excess of the number of furnaces;
  • the addition of alloying elements is small, energy consumption is significantly lower than the existing technology, the use value High, the production cost is greatly reduced, the whole process is easy to implement, the operation is relatively simple, and it is suitable for industrialization and has significant progress.

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Abstract

一种基于镁合金废料生产国标镁合金锭的方法，包括以下步骤：步骤a，对镁合金废料进行分拣除杂、清洗和干燥，清洗包括依次进行的高压清洗、酸洗和水洗；步骤b，将步骤a所得镁合金废料进行预热、加料熔融、精炼除杂和合金化，获得镁合金液；步骤c，将步骤b所得镁合金液进行铸锭，获得国标镁合金锭。该方法直接以镁合金废料为原料生产国标镁合金锭，不需添加价格昂贵的高纯镁，有害元素达标的炉次占总炉次的98％以上，略超标的占2％，无严重超标的炉次；此外，合金元素加入量少，能耗较现有技术明显降低，使用价值高，生产成本大幅降低，整个工艺流程易实现，操作相对简单，适用于产业化。

Description

基于镁合金废料生产国标镁合金锭的方法 技术领域
本发明涉及一种镁合金废料的回收再利用方法，具体是一种采用报废镁合金产品为原料生产国标镁合金锭的方法，属于化工技术领域。
背景技术
在有色金属合金中，镁合金具有密度小、刚性好、耐腐蚀、抗冲击、耐摩擦、不变形、无毒、无磁性、导热导电性好、阻尼减震和电磁屏蔽性能优异及易于加工成型和易于回收等优点；并且同样体积的镁合金比铝合金轻36％，比锌合金轻73％，镁合金正成为现代汽车电子通信等行业的首选材料，广泛用于航空、航天、电子、汽车、计算机、电信等领域，被誉为21世纪的绿色工程材料。
镁合金制造的汽车零部件，可减轻汽车自重、提高燃料利用率、减少环境污染；采用镁合金制造飞机、导弹、飞船、卫星、轻武器等重要武器装备零部件，意味着武器射程、命中率和飞行器机动性能的提高，航天器发射成本降低；镁合金用于制造手机、笔记本电脑和数码相机等数字产品的外壳，具有强度高、美观及电磁屏蔽等优点。由于镁合金在这些领域的扩展，从20世纪90年代开始，在全球范围内，镁的用量已连续10年保持年增长率大于20％，1990年产镁26万吨，到2002年产镁46万吨，2005年镁的产量达到61万吨。然而，由于金属矿藏属于不可再生资源，不仅过度开发利用金属矿藏违背了可持续发展的战略，且开发利用后产生的大量金属产品废弃物、尤其是重金属产品废弃物，将持续污染环境。中国有色金属协会数据显示，2013年中国的原镁产量为76.97万吨，同比增长10.22％，镁合金的产量为29.78万吨，同比增长43.52％，镁合金产量的急剧增长势必引起镁合金废料的快速增加。所以，废旧镁合金产品的回收利用既能减轻对其原料金属矿藏的需求负担，又能缓解重金属产品废弃物对自然环境的污染压力，是中国乃至世界都需重点研究的方向。由于镁合金废料具有再生率高、能耗低的优点，其再生率可达95％以上，且回收再生能耗只有原镁生产能耗的5％左右。因此镁合金废料的合理再生利用直接影响镁及镁合金行业发展的合理性及可持续性。
镁合金废料的分类分级有助于加强镁合金废料的回收利用，从而达到节约资源和降低 生产成本的目的。镁合金分类分级国际标准提案将镁合金废料分为8级，见表a。
表a镁合金废料分级
Figure PCTCN2015074840-appb-000001
当镁合金废料分类分级完成后，可根据不同的废料等级采取不同的方法进行处理：①已分类的清洁废料可直接入炉熔炼；②已分类的清洁废料，但其中混有木制夹杂物和钢铁夹杂物的废料须将夹杂物去除后方可入炉熔炼；③沾有油漆、油污的废料须将油漆和油污去除后再入炉熔炼；④干燥、清洁的机加工碎屑和切屑经过压力机压成块状后加入炉中熔炼；⑤沾有油和水的机加工碎屑和切屑最好的办法是用专门的炉子在高温和真空下汽化后进行回收(杨明波等，镁合金废料回收技术的现状及进展[J],铸造，2005,54(5):420-424)。现有技术对镁合金废料的回收技术通常是指对1～5级镁合金废料的回收，一般采用熔剂精炼法和/或无熔剂精炼法对镁合金废料进行除杂后压铸成新的镁合金锭(王晓明等，压铸高危镁合金废料回收技术与设备研发[J],特种铸造及有色合金，2011,31(12):1127-1131)。
由表a可知，报废的镁合金产品是镁合金废料的重要来源，包括报废的汽车轮毂、方向盘、发动机缸盖，飞机机身、蒙皮，电脑及相机的外壳等，总量在20万吨/年以上。该类型废料虽然本身品质高，但由于在生产和使用过程中，废料表面会形成大量的油污、泥垢及氧化层等，处理难度较大，国内对其处理方式是作为生产消耗品和非标镁合金锭的原料，如作为烟花发色剂、脱硫剂及非标镁合金锭的原料，此类方法是将镁合金废料降级使用， 使其不可再生，不仅降低了产品的价值，还是对镁资源的极大浪费，从而限制了其高效、高价值回收利用。
国标镁合金锭是制备镁合金铸件的重要原料，目前普遍采用的国标镁合金锭制备工艺是以纯镁及所需的合金元素为原料，通过熔融、精炼、合金化等工序获得成分满足国标要求的镁合金液，而后浇注成锭。该工艺对所需的纯镁及合金原料的成分要求严格，满足要求的纯镁锭及合金原料价格昂贵，使制备国标镁合金锭的生产成本大大提高。
由于报废的镁合金铸件本身品质高，限制其利用的主要因素是废料表面的油污、泥垢及氧化层等，如果能采用合理的预处理工艺彻底清除废料表面的杂质，理论上报废镁合金铸件在成分上可以满足作为制备国标镁合金锭的原料要求，以镁合金废料重熔再生国标镁合金锭所需的能量仅3KWh/kg左右，比生产一次国标镁合金锭降低一个数量级以上，节能效果显著。中国发明专利CN 101736160 B公开了一种镁合金低级废料的回收方法，采用机械切割、重复酸洗、水洗、电阻炉熔炼、精炼、浇铸成锭，制成镁合金低级废料锭，但其化学成分仅接近镁合金锭的成分量值指标，力学性能也只是接近镁合金锭的量值，限制了其应用范围。又如中国发明专利申请CN 101338378 A公开了一种废弃镁合金零件重熔铸造获得镁合金锭的工艺，该方法采用3～5mm的钢丸对废料机械打磨30～40min，导致不规则形状废料打磨效果不均匀，废料沟槽处的打磨效果差，且其凸面磨损严重；喷丸过程会有大量的镁合金粉产生，在钢丸的冲击下存在安全隐患；重熔铸锭过程中无合金化步骤，很难获得成分满足国标要求的镁合金锭。
至今为止，还未出现以报废镁合金产品为原料铸造国标镁合金锭的方法及工艺，其局限性在于，报废镁合金产品表面预处理的清理程度不够彻底，以致杂质太多，完全使用报废镁合金产品作为原料生产国标镁合金锭的难度太大，且目前并未有人公开任何相关技术资料，现阶段生产国标镁合金锭的主要方法仍然是在高纯镁中加入合金元素生产，仅有少部分厂家在生产镁合金时会加入少量的纯净度相对较高的镁合金铸造边角料及不合格铸件，而添加比例仅在20％以下，并未真正缓解大量待处理镁合金废料回收利用的压力，所以，现有技术并没有提供一种切实可行的全部以镁合金废料、尤其是以报废镁合金产品为原料铸造国标镁合金锭的工艺或方法。
发明内容
针对现有技术存在的不足，本发明的目的是提供一种国标镁合金锭的生产制备方法， 该方法可直接采用报废镁合金产品为原料用于生产国标镁合金锭，无需添加价格昂贵的高纯镁，且只需添加少量其他合金原料。
为实现上述发明目的，本发明采用的技术方案如下：
基于全镁合金废料生产国标镁合金锭的方法，包括以下步骤：
步骤a，对镁合金废料进行分拣除杂、清洗和干燥，清洗包括依次进行的高压清洗、酸洗和水洗；
步骤b，将步骤a所得镁合金废料进行预热、加料熔融、精炼除杂和合金化，获得镁合金液；
步骤c，将步骤b所得镁合金液进行铸锭，获得国标镁合金锭。
优选地，上述镁合金废料选自镁及镁合金废料分类分级国际标准提案中的报废镁合金铸件废料。
优选地，步骤b或步骤c在低氧或无氧条件下进行，以工作环境为惰性气体为佳，优选为N2或SO2。
优选地，由于某些报废镁合金产品体积较大且形状不规则，分拣除杂时很多螺丝、橡胶无法被分离出来，且大件的镁合金废料通常为中空结构，堆积密度小，所以步骤a中镁合金废料分拣除杂前还经过切割。
优选地，步骤a中高压清洗的压力为5～20MPa，优选为10～15MPa。
更优选地，步骤a包括将镁合金废料进行切割、除杂、高压清洗、酸洗、水洗和干燥；其中，可分为以下步骤：
步骤a1：将大块镁合金废料切割成若干块体积较小的镁合金废料，以便将含螺丝、橡胶的镁合金料分离，并满足后续处理设备对原料尺寸的要求；
步骤a2：将切割后的镁合金废料分拣除杂，筛除无法从镁合金废料中分离的杂质；
步骤a3：对分拣除杂后的镁合金废料进行高压清洗，以除去镁合金废料表面的灰尘、油污、泥垢或疏松氧化层；
步骤a4：对高压清洗后的镁合金废料进行酸洗；
步骤a5：对酸洗后的镁合金废料进行水洗；
步骤a6：干燥水洗后的镁合金废料。
更优选地，步骤a还包括步骤a7：将干燥后的镁合金废料再次分拣，获得干净废料；其中，干净废料定义：有害元素的含量在国标范围内的镁合金废料，其中，有害元素是指即使少量存在也会显著降低镁合金的某些性能(包括耐腐蚀性能、力学性能等)的元素， 如Si、Cu、Ni、Fe等。
更优选地，步骤a1的具体操作为：采用金属破碎机将镁合金废料进行切割，其中切割后镁合金废料的各方向的尺寸均不大于300mm，优选为50～300mm，最佳为100mm，具体根据待处理镁合金废料尺寸及设备情况决定。
更优选地，步骤a2的具体操作为：将无法分离的含螺丝、橡胶及塑料的废料、表面有有机涂层的废料及非镁料从步骤a1所得镁合金废料中分拣出来，换言之，是将镁合金废料中含有的螺丝、橡胶、塑料等物从镁合金废料中进行分离，再将留下的镁合金废料备用。
更优选地，步骤a3的具体操作为：将步骤a2所得镁合金废料置于固料装置内，使用高压清洗机对固料装置内的镁合金废料进行高压清洗；固料装置定义：固料装置是一种将镁合金废料固定在一定范围内，同时使废料能够在此范围内随机翻转的盛料装置，它不仅能够避免废料在高压水的冲击下被冲跑，而且可保证废料各部分被均匀清洗。
进一步，高压清洗的固料优选为通过网孔(镂空)滚筒实现，或其它现有技术中的固料方法，具体可视本发明实施场所的生产条件而定；其中，该网孔滚筒的孔径小于50mm，在保证滚筒强度能承受高压水的冲击压力的前提下，使滚筒单位面积的网孔数目达到最大，具体数目可视滚筒材料、高压清洗的压力或网孔孔径等条件调整，从而使高压清洗产生的水溶液能够及时排出，以免清洗液不能直接冲击在废料上，影响清洗效果。
作为一种优选方案，固料装置为一电驱动的网孔滚筒，通过电驱动该网状滚筒转动，从而使镁合金废料随网孔滚筒的旋转动而随机翻转。
更优选地，由于使用高压水清理镁合金废料表面、尤其是镁合金废料的沟槽内的杂质时，水的冲击力大于杂质与镁合金废料表面附着力，所以强力水压产生的泡沫足以将一般杂质剥离、冲走，所以高压清洗为一次高压清洗；但在清洗过程中，当待处理镁合金废料表面有油污或脱模剂时，由于油污表面通常粘附有一层较厚的油污及泥垢形成的混合杂质层，虽然高压水因其压力能冲走混合杂质层，但由于水和油互不相溶，其无法将附着在镁合金废料表面的油污或脱模剂完全除去，还需进一步加入能除去油污或脱模剂的清洗剂，因此发明人又将高压清洗分为两次高压清洗，分别为一次高压清洗和再次高压清洗，一次高压清洗的高压水能除去镁合金废料表面的杂质，再次高压清洗中加入了清洗剂的高压水能轻易的除去其表面的油污或脱模剂，并进一步除去泥垢及疏松氧化层。
作为进一步优选方案，清洗剂为除油剂，除油剂的种类和浓度可根据废料表面油污的种类及多少而定，优选为水基类金属除油剂，最佳为酸性水基类金属除油剂，也可为现有技术其它除油剂如金属乳化剂或生物分解剂等。
进一步，高压清洗的清洗液为水和/或清洗剂，清洗液pH值为5～7。
进一步，一次高压清洗的清洗液为水，清洗时间为10～30min；再次高压清洗的清洗液为加入了清洗剂的水溶液，清洗液温度为40～70℃，清洗时间为5～10min，高压清洗的具体清洗时间或清洗温度可根据油污的严重程度来确定。
更优选地，步骤a4的具体操作为：将步骤a3所得镁合金废料放入酸洗池中进行酸洗，以除去镁合金废料表面的氧化层。
进一步，酸洗时间为30～90s，酸洗的酸洗液pH值为1～3；酸洗液为盐酸、硝酸、硫酸或草酸溶液中的一种或以上的混合液，具体根据镁合金废料表面的氧化程度决定。
进一步，酸洗液可反复多次使用，为保证酸洗液pH范围，每次根据酸洗液的pH值补充适量浓度酸至pH值为1～3即可，当溶液中的Mg2+浓度大于2.0mol/L时，对酸洗液进行更换；酸洗产生的废酸通过中和、过滤、蒸发结晶及干燥步骤进行回收处理，处理过程为：采用MgO或MgCO3对废酸进行中和处理，使其pH值为7左右，而后过滤，滤液去除水分后获得干燥镁盐；获得的干燥镁盐纯度相对较高，多用于制备镁化肥原料。
更进一步，过滤采用压滤机。
更进一步，滤液去除水分通过蒸发、浓缩、过滤、干燥实现，或其他现有技术中的去除水分方法，如真空干燥技术等，可视本发明实施场所的条件而定。
更进一步，滤液蒸发、浓缩、过滤和干燥通过结晶器及其配套的过滤器和干燥器共同完成。
更优选地，步骤a5的具体操作为：用水将步骤a4所得镁合金废料表面残留的酸液及杂质除去，优选为漂洗法或喷淋法，或现有技术的其他水洗方法，可视本发明实施场所的条件而定。
更优选地，步骤a6的具体操作为：将步骤a5所得镁合金废料表面残留的水分除去，优选为风切法或烘干法，或现有技术的其它水洗方法，可视本发明实施场所的条件而定，此时镁合金废料的预处理完成；风切法的定义：风切是单纯采用高压风的冲击能量使废料表面水珠脱离废料，减少热风烘干的时间和压力，降低废料的氧化，通常不采用热风。
更优选地，步骤a7的具体操作为：将步骤a6所得镁合金废料中的不干净废料及非镁料分选出来，从而得到干净废料。
优选地，步骤b包括将步骤a所得的镁合金废料进行预热、熔融、检测有害元素、精炼、合金化、捞渣和控温静置，其中，可分为以下步骤：
步骤b1：将步骤a所得镁合金废料进行预热，以除去水汽，避免水汽引起爆炸，同时可 减少由水汽引起的气体夹杂；
步骤b2：将步骤b1所得镁合金废料加热至熔融；
步骤b3：检测步骤b2所得的镁合金液中各有害元素的具体含量，根据其具体含量选择是否制备国标镁合金锭；
步骤b4：将步骤b3检测所得用于制备国标镁合金锭的镁合金液进行精炼；
步骤b5：将步骤b4所得镁合金液进行合金化；
步骤b6：检测步骤b5所得镁合金液中各金属元素的具体含量；
步骤b7：分析步骤b6检测的除元素铁外的各金属元素的具体含量是否达标：若达标，进行下一步骤，若不达标，重复进行步骤b5和步骤b6至达标；
步骤b8：将步骤b7分析得到的达标镁合金液进行捞渣；
步骤b9：对步骤b8所得镁合金液进行控温、静置；
步骤b10：检测并分析步骤b9所得镁合金液的元素铁的具体含量是否达标，达标后可进入步骤c。值得一提的是，为了降低成本、节约时间，还可以在对镁合金液合金化过程的同时进行再次精炼，以得到纯度更高的镁合金液。
更优选地，步骤b6采用铸造镁合金锭GB/T 19078-2003为准检测镁合金液中各金属元素是否达标。
更优选地，步骤b1的具体操作为：将干净废料放入烘箱内，并通过抽气装置将蒸发产生的水汽排出。
进一步，步骤b1的预热温度为120～150℃。
进一步，步骤b1的预热时间为5～20min。
更优选地，步骤b2的具体操作为：将预热后的镁合金废料分次加入熔炼炉中，加料过程中逐步撒入熔解剂(熔解剂为60-100kg/吨)，用于覆盖灭火。
进一步，熔炼炉中炉膛温度为850-950℃。
进一步，熔解剂为现有技术中的常规合金熔解剂，如二号熔剂，将根据实际生产中所需制备的镁合金锭择优选择，在此不作为本发明所公开的制备方法的限定。
作为一种优选方案，为降低熔炼炉中的镁合金废料的烧损，可将镁合金废料分次加入熔炼炉中至熔融，首次加入的镁合金废料量为熔炼炉总容量的1/3～1/4，此后每次镁合金废料的添加量为熔炼炉总容量的1/4～1/5，直至加满熔炼炉，熔炼炉总容量根据生产国标镁合金锭的需求选择，优选为1t、2t或3t；每次加料后都应在镁合金废料表面均匀撒一层熔解剂，避免高温引起镁合金燃烧。
更优选地，针对所需制备的各类国标镁合金锭及步骤b3的各元素分析结果，选择性进入步骤b4，以获得不同型号的合金化产品；即步骤b3检测的各有害元素的含量符合国标要求，则用其制备国标镁合金锭，否则可用于制备非标镁合金锭；本发明提供的方法可直接采用镁合金废料制备AZ91D国标镁合金锭；此外，如需制备其他牌号的国标镁合金锭，如AM50A/AM60B等，可通过添加纯镁对主要元素进行适当稀释以实现含量达标，纯镁加入量可根据具体牌号确定。
更优选地，步骤b4的具体操作为：将加热至熔融的镁合金废料送入熔炼炉中，均匀加入精炼剂，搅拌，搅拌过程中采用精炼剂进行覆盖灭火。
更优选地，步骤b5的具体操作为：将步骤b4所得镁合金液取样分析，根据分析结果确定各合金元素加入量，而后向步骤b4所得镁合金液加入合金原料，在合金原料熔融过程中均匀加入的精炼剂，搅拌，搅拌过程中采用精炼剂进行覆盖灭火，即同时进行合金化及再次精炼。
进一步，步骤b4或b5中均匀加入精炼剂，优选为少量多次加入精炼剂，总添加量为15～25kg/t；精炼时间为15～30min；搅拌为机械搅拌和/或气体喷吹；精炼过程中全程搅拌。
进一步，搅拌时采用氮气配合搅拌机全方位搅拌。
进一步，步骤b4精炼温度为710～730℃。
进一步，步骤b5精炼温度为720～740℃。
进一步，精炼过程中使用的精炼剂为现有技术中所有用于合金精炼的精炼剂，例如2号熔剂与萤石粉的复合熔剂，萤石粉的配比在10％～25％之间，将根据实际生产中所需制备的镁合金锭择优选择，在此不作为本发明所公开的制备方法的限定。
更优选地，步骤b5进行合金化时各金属元素的选用标准如下：
Mg：一级及以上镁锭；
Al：一级及以上铝锭；
Zn：一级及以上锌锭；
Mn：高纯Al-Mn合金、纯度大于99.8％的金属锰粉、或纯度大于99.8％的无水氯化锰中一种；
Be：高纯Al-Be合金。
进一步，Be元素由于容易氧化和挥发，为减少其损耗，通常在精炼后期加入。
进一步，合金的加入依次为Mn、Al和Zn、Mg(根据实际情况确定是否要加)，最后加入Be。此处应当说明的是，上述五种合金元素的添加顺序仅当需要添加时的加入顺序，而 非固定添加顺序；如无需添加Mg时，则合金元素的添加顺序为Mn、Al和Zn，最后加入Be。
更优选地，步骤b8的具体操作为：采用捞渣包对合金化/再次精炼后的镁合金液进行捞渣，再采用干燥氮气进行吹喷，使沉入熔炼炉底部的镁渣重新被吹上来，镁渣在再次沉下的过程中落入捞渣桶中，由于镁渣密度较大，会逐渐将捞渣桶中的镁液挤出，从而达到捞渣的目的。
更优选地，步骤b9的具体操作为：将步骤b8所得镁合金液静置，同时对其控温，即将步骤b8所得镁合金液降温后升温，可采用现有技术中的降温方法，如对炉膛喷吹冷空气或加入适量国标镁合金锭的方法辅助降温，温度降至640±5℃后立即升温至660～670℃，以除去镁合金液中的杂质铁。
进一步，静置时间为40min。
进一步，步骤b9所需时间为静置时间或控温时间，时间以后到达的为准。
更优选地，步骤b6或步骤b10采用原子发射光谱仪进行光谱分析，或现有技术其它合金元素检测方法及仪器进行检测，在此不再赘述。
更优选地，将步骤b10检测的达标镁合金液备用，或转移至保温炉中，采用硫磺粉或SO2与N2的混合气体进行保护，用覆盖剂对未能完全转移的镁合金液进行保护；便于镁合金液进一步静置，便于后续铸锭。
进一步，保温温度为640～670℃。
作为一种优选方案，采用移液泵或移液包对镁合金液进行转移；其中，移液泵及移液管或移液包在使用前预热。
更优选地，步骤c包括以下步骤：
步骤c1：将锭模预热，并在锭模内表面均匀涂覆一层脱模涂料；
步骤c2：对浇铸泵及浇铸管道进行预热；
步骤c3：连接浇铸泵及管道，开动浇铸机，开始浇铸。
更优选地，将浇注完成的镁合金锭均匀冷却，以免出现偏析现象。
更优选地，预热温度为150～220℃；浇注温度为660～670℃。
更优选地，步骤c还包括步骤c4：对步骤c3所得镁合金锭进行抛光、喷码或打码及打包等后处理。
与现有技术相比，本发明的优势在于：
(1)本发明可直接以镁合金废料为原料，尤其适用于全部以报废镁合金产品为原料，生产国标镁合金锭，使用价值高，生产成本大幅降低；
(2)本发明的预处理工艺清洗除杂效果优异，熔炼方法先进合理，二者结合有效实现了全部以镁合金废料为原料生产国标镁合金锭，不需添加价格昂贵的高纯镁；
(3)预处理工艺中的酸液可循环利用，产生的废酸还可制备作为镁化肥原料的高纯度镁盐，实现酸洗废水零排放，经济环保；
(4)镁合金废料本身含有一定量的合金元素，合金化时只需添加少量合金元素即可获得合格的镁合金液，所需添加的合金元素大幅降低，从而可进一步降低生产成本；
(5)精炼后所得的镁渣可通过发明人先期进行的研究(专利申请号：PCT/CN2014/075237)进行无害化处理，获得高纯度氧化镁，可最大程度降低对环境的污染，三废循环高效利用，满足节能减排的要求，从而具备极佳的经济效益和环境效益；
(6)能耗相对较低，采用镁合金废料重熔再生镁合金锭所需能耗可降低至不足生产一次镁合金锭的10％；
(7)整个工艺流程易实现，操作相对简单，节能环保，环境友好，适用于产业化。
具体实施方式
下面结合实施例对本发明作进一步详细、完整地说明，但不应视为对本发明的限定。
下述实施例中采用的各试剂如无其它说明均为市售品种，根据其说明书或其相应标准使用；此外，下述实施例中采用的熔解剂均为滨海县恒旺轻金属熔剂有限公司生产的熔解剂，精炼剂均为滨海县恒旺轻金属熔剂有限公司生产的精炼剂。
实施例1
本实施例采用湖南斯瑞摩科技有限公司从瑞典进口的批号为2013-10-05-A的报废镁合金产品为原料生产AZ91D镁合金锭，该批次镁合金废料合计5000t，其表面含油污及脱模剂的废料比例在总量的10％左右，生产步骤如下：
(1)切割：采用金属破碎机将镁合金废料切割成最大方向尺寸为100mm的小块废料；
(2)分拣除杂：将无法分离的含螺丝橡胶及塑料的废料、表面有有机涂层的废料及非镁料从切割后的镁合金废料中分拣出来，将留下的镁合金废料备用；
(3)一次高压清洗：采用895-1型重型热水高压清洗机对分拣除杂后的镁合金废料进行一次高压清洗，清洗液为水，压力为10MPa，清洗时间为20min；
(4)再次高压清洗：采用895-1型重型热水高压清洗机对一次高压清洗后的镁合金废料进行再次高压清洗，清洗液为添加了酸性水基类金属除油剂的水溶液，按配方配制的水溶 液的pH值为5.5，水溶液温度为55℃，压力为10MPa，清洗时间为10min；
(5)酸洗：将再次高压清洗后的镁合金废料放入pH值为1.0左右的稀盐酸溶液中进行酸洗，酸洗时间为40s；
(6)水洗：采用漂洗与喷淋相结合的方式将得到的镁合金废料表面残留的酸液及杂质除去；
(7)干燥：采用风切与热风烘干相结合的方式将清洗后的镁合金废料表面残留的水分除去；
(8)再次分拣：将干燥后的废料中的不干净废料及非镁料分选出来，镁合金废料的预处理完成；
(9)预热：将分拣后的干净废料放入烘箱内，预热10min至预热温度为130℃，并通过抽气装置将蒸发产生的水汽排出；
(10)加热熔融：将预热后的镁合金废料分批加入高温熔炼炉中，加料过程中逐步撒入8％的熔解剂，用于覆盖灭火；炉膛温度为850-950℃；
(11)精炼：分批均匀撒入精炼剂，采用机械搅拌和气体喷吹进行搅拌，搅拌过程中采用精炼剂进行覆盖灭火；精炼时间为20min，精炼温度为720℃；
(12)取样分析：将上述所得镁合金液进行一次光谱取样(记为1#样品)分析，根据分析结果确定有害元素(如Si、Cu、Ni等)是否超标，如果严重超标，可直接浇铸非标镁合金锭，如略微超标，可采用纯镁稀释法将超标元素降至合格范围，如达标，则根据分析结果确定合金化各元素(如Al、Zn、Mn等)所需添加的量；与本实施例中，测得有害元素结果及所需补充的其它金属元素添加量见表1.1：
表1.1.1#样品光谱检测结果
元素种类 Al Zn Mn Si Fe Cu Ni Be Mg
含量(％) 6.89 0.345 0.187 0.039 0.007 0.0072 0.0005 0.0003 余量
由表1.1中数据可知，有害元素Si、Cu、Ni等都在国标范围内，可直接进行后续的合金化/精炼操作。根据表1.1计算合金元素Al、Zn、Mn、Be所需添加量，计算结果见表1.2：
表1.2.合金化过程中需要添加的合金元素的量
需添加元素种类 Al Zn Mn 含铍1.0％Al-Be
添加总量 65.0Kg 9.5Kg 4.0Kg 4.5Kg
注：取样时镁合金液的重量为2950Kg。
(13)合金化/精炼：根据表2依次加入各合金原料，在合金原料熔融过程中均匀加入2％ 的精炼剂，采用机械搅拌和气体喷吹进行搅拌，搅拌过程中采用精炼剂进行覆盖灭火；合金化/精炼时间为15min，温度为740℃；
(14)取样分析：对上述步骤所得镁合金液进行光谱取样(记为2#样品)分析，达标后可进行后续处理；若不达标，所得镁合金液再次进行合金化/精炼，检测及分析结果见表1.3：
表1.3.2#样品光谱分析结果
元素种类 Al Zn Mn Si Fe Cu Ni Be Mg
含量(％) 9.01 0.632 0.321 0.040 0.006 0.0073 0.0005 0.0014 余量
由表1.3可知，该镁合金液中除Fe外的各合金元素已达标，无需再次进行合金化/精炼；
(15)捞渣：将充分预热的捞渣桶缓慢放入镁合金液中，直至沉入熔炼炉底部，然后采用干燥N2喷吹的方式将镁渣从底部吹起来，由于镁渣比重比镁合金液大，镁渣会逐渐沉入捞渣桶中，从而达到捞渣的目的；
(16)控温静置：静置前根据镁液温度加入适量国标合金锭，使镁液降温至640±5℃，而后立即升温至660～670℃，最后将镁合金液静置，静置时间大于40min；
(17)取样分析及后续处理：将控温静置后的镁合金液进行取样(记为3#样品)分析，如达标可根据生产实际情况，直接将静置后的镁合金液进行铸锭，或将静置后的镁合金液转移至保温炉；如不达标，可根据需要补充适量的合金原料，然后再进行铸锭或转液操作；转液过程中，采用硫磺粉对熔炼炉中剩余的镁合金液进行灭火，未能完全转移的镁合金液采用覆盖剂进行保护，保温炉中采用惰性气体进行覆盖保护；其中检测分析结果见表1.4：
表1.4.3#样品光谱检测结果
元素种类 Al Zn Mn Si Fe Cu Ni Be Mg
含量(％) 8.98 0.629 0.250 0.039 0.003 0.0070 0.0005 0.0012 余量
由表1.4可知，检测的镁合金中的各合金元素均在国标规定范围之内，可继续后续转液-铸锭操作；
(18)锭模预处理：将锭模预热至180℃，并在锭模内表面均匀涂覆一层脱模涂料；
(19)浇注：对浇铸泵及浇铸管道进行预热，连接浇铸泵及管道，开动浇铸机，开始浇铸；
(20)后处理：将浇注后所得镁合金锭进行抛光、打码及打包等后处理。
经检测，本实施例所生产的镁合金锭各成分完全符合国家标准；氯离子含量为0.0010％，熔剂夹渣少。此外，本实施例中镁合金液，1#样品有害元素达标的炉次占总炉次的98％以上，略超标的占2％，无严重超标的炉次。
实施例2
本实施例与实施例1的差别在于步骤11精炼中经步骤12测得分析的有害元素含量不同，具体结果见表2.1：
表2.1精炼后镁合金液的光谱分析结果
元素种类 Al Zn Mn Si Fe Cu Ni Be Mg
含量(％) 7.12 0.321 0.201 0.053 0.008 0.0079 0.0007 0.0003 余量
注：取样时镁合金液的重量为2550Kg。
从表2.1中可以看出，有害元素Si含量略微超标，需要采用添加纯镁的方式降硅，通过计算，纯镁的所需添加量为400Kg。添加纯镁后对熔体充分搅拌，再次取样进行有害元素含量分析，具体结构见表2.2：
表2.2补充纯镁后的镁合金液的光谱分析结果
元素种类 Al Zn Mn Si Fe Cu Ni Be Mg
含量(％) 6.21 0.280 0.178 0.046 0.008 0.0081 0.0008 0.0002 余量
从表2.2中可以看出，有害元素Si的含量为0.046％，符合国家标准，可直接进行后续的合金化/精炼操作。
因添加了纯镁，故后续工序中合金化时所需添加的合金原料的量有所调整，其他操作与实施例1一致；根据表2.1和2.2计算合金化过程中需要添加的合金元素的量，具体结果见表2.3：
表2.3合金化过程中需要添加的合金元素的量：
表2.3.合金化过程中需要添加的合金元素的量
需添加元素种类 Al Zn Mn 含铍1.0％Al-Be
添加总量 84.0Kg 11.0Kg 5.0Kg 5.0Kg
后续检测的镁合金液中各合金元素含量见表2.4：
表2.4.2#样品光谱分析结果
元素种类 Al Zn Mn Si Fe Cu Ni Be Mg
含量(％) 8.96 0.638 0.310 0.045 0.006 0.0079 0.0007 0.0013 余量
由表2.4可知，该镁合金液已达标，且其中除Fe外的各合金元素均在国标规定范围之内，可继续后续操作。
经检测，本实施例所生产的镁合金锭各成分完全符合国家标准；氯离子含量为0.0010％，熔剂夹渣少。此外，本实施例中镁合金液，2#样品有害元素达标的炉次占总炉次的98％以上，略超标的占2％，无严重超标的炉次。
实施例3
本实施例与实施例1的差别在于，目标镁合金锭为AM60B；由于目标镁合金锭不同，故所需添加的合金元素亦不同。
根据步骤12的光谱分析结果调整后续操作，光谱分析具体结果见表3.1
表3.1光谱分析结果
元素种类 Al Zn Mn Si Fe Cu Ni Be Mg
含量(％) 6.98 0.332 0.198 0.038 0.008 0.0069 0.0007 0.0003 余量
注：取样时镁合金液重量约1650Kg。
从表3.1中可知，主要元素中铝和锌含量超标，尤以锌超标幅度较大，需添加纯镁进行降锌处理，同时需补充铝、锰及铍，通过计算，添加的各组分的种类及重量见表3.2所示：
表3.2合金化过程中所需添加的各原料的种类及量
添加原料种类 纯镁 铝锭 锰粉 1.0％的铝铍合金
添加量(Kg) 1300 60 7.0 5.0
根据表3.2添加各原料，充分搅拌后再次光谱取样分析，具体结果见表3.3：
表3.3添加各组分后的光谱分析结果
元素种类 Al Zn Mn Si Fe Cu Ni Be Mg
含量(％) 5.96 0.188 0.385 0.025 0.008 0.0075 0.0008 0.0015 余量
由表3.3可知，该镁合金液已达标，且其中除Fe外的各合金元素均在国标规定范围之内，可继续后续操作。
经检测，本实施例所生产的镁合金锭各成分完全符合国家标准；氯离子含量为0.0010％，熔剂夹渣少。此外，本实施例中镁合金液，3#样品有害元素达标的炉次占总炉次的98％以上，略超标的占2％，无严重超标的炉次。
对比例1
本对比例与实施例1的差别在于，本对比例不进行预处理工艺，后续步骤操作和参数与实施例1一致，熔融精炼后获得的镁合金液取样光谱分析，结果如下表所示：
表a不进行预处理工艺获得的镁合金液光谱分析结果
元素种类 Al Zn Mn Si Fe Cu Ni Be Mg
含量(％) 7.56 0.452 0.286 0.326 0.025 0.152 0.052 0.0004 余量
从表a中可以看出，有害元素Si、Fe、Cu、Ni严重超标，不具备生产国标镁合金锭的产业化条件，仅能浇铸生产非标镁合金锭。
对比例2
以传统工艺制备与实施例1相同的AZ91D镁合金锭，则合金化所需添加的各合金原料的量如下表b：
表b合金化添加元素种类及重量
需添加元素种类 Al Zn Mn 含铍1.0％Al-Be
添加总量 270Kg 19.5Kg 9.0Kg 5.0Kg
由表b可知，采用传统工艺制备与实施例1相同的镁合金锭，不但需要以纯镁为原料，且所需添加的各合金元素的量明显高于本发明的添加量，故本发明提供的镁合金锭生产方法所需原料量更低，成本更低，且利于物料循环利用，节能环保。
综上述实验结果可知，采用本发明提供的生产国标镁合金锭的方法直接以镁合金废料为原料，尤其适用于全部以报废镁合金产品为原料，生产国标镁合金锭，不需添加价格昂贵的高纯镁，有害元素达标的炉次占总炉次的98％以上，略超标的占2％，无严重超标的炉次；此外，合金元素加入量少，能耗较现有技术明显降低，使用价值高，生产成本大幅降低，整个工艺流程易实现，操作相对简单，适用于产业化，具有显著的进步。
最后有必要在此说明的是：以上实施例只用于对本发明的技术方案作进一步详细地说明，不能理解为对本发明保护范围的限制，本领域的技术人员根据本发明的上述内容作出的一些非本质的改进和调整均属于本发明的保护范围。

Claims (48)

  1. 基于镁合金废料生产国标镁合金锭的方法，其特征是，包括以下步骤：
    步骤a，对镁合金废料进行分拣除杂、清洗和干燥，清洗包括依次进行的高压清洗、酸洗和水洗；
    步骤b，将步骤a所得镁合金废料进行预热、熔融、精炼除杂和合金化，获得镁合金液；
    步骤c，将步骤b所得镁合金液进行铸锭，获得国标镁合金锭。
  2. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述镁合金废料选自镁及镁合金废料分类分级国际标准提案中的报废镁合金铸件废料。
  3. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤b或步骤c在低氧或无氧条件下进行。
  4. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤a中镁合金废料分拣除杂前还经过切割。
  5. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤a中高压清洗的压力为5～20MPa。
  6. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤a中高压清洗的压力为10～15MPa。
  7. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤a包括将镁合金废料进行切割、分拣除杂、高压清洗、酸洗、水洗和干燥；分为以下步骤：
    步骤a1：将大块镁合金废料切割成若干块体积较小的镁合金废料；
    步骤a2：将切割后的镁合金废料分拣除杂，筛除无法从镁合金废料中分离的杂质；
    步骤a3：对分拣除杂后的镁合金废料进行高压清洗；
    步骤a4：对高压清洗后的镁合金废料进行酸洗；
    步骤a5：对酸洗后的镁合金废料进行水洗；
    步骤a6：干燥水洗后的镁合金废料。
  8. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤a还包括步骤a7：将干燥后的镁合金废料再次分拣，获得干净废料。
  9. 如权利要求7所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤a1的具体操作为：采用金属破碎机将镁合金废料进行切割，切割后镁合金废料的各方向的尺寸均不大于300mm。
  10. 如权利要求7所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤a2的具体操作为：将无法分离的含螺丝、橡胶及塑料的废料、表面有有机涂层的废料及非镁料从步骤a1所得镁合金废料中分拣出来。
  11. 如权利要求7所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤a3的具体操作为：将步骤a2所得镁合金废料置于固料装置内，使用高压清洗机对固料装置内的镁合金废料进行高压清洗。
  12. 如权利要求11所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述高压清洗的固料通过网孔滚筒实现。
  13. 如权利要求12所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述网孔滚筒的孔径小于50mm。
  14. 如权利要求11所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述固料装置为一电驱动的网孔滚筒，通过电驱动该网状滚筒转动，使镁合金废料随网孔滚筒的旋转动而随机翻转。
  15. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述高压清洗为一次高压清洗。
  16. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：当待处理镁合金废料表面有油污或脱模剂时，所述高压清洗包括一次高压清洗和再次高压清洗。
  17. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征在于：所述高压清洗的清洗剂为除油剂。
  18. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述高压清洗的清洗液为水和/或清洗剂。
  19. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述高压清洗的清洗液pH值为5～7。
  20. 如权利要求14或15所述的基于镁合金废料生产国标镁合金锭的方法，其特征在于：所述一次高压清洗的清洗液为水。
  21. 如权利要求15或16所述的基于镁合金废料生产国标镁合金锭的方法，其特征在于：所述一次高压清洗的清洗时间为10～30min。
  22. 如权利要求16所述的基于镁合金废料生产国标镁合金锭的方法，其特征在于：所述再次高压清洗的清洗液为加入了清洗剂的水溶液。
  23. 如权利要求9所述的基于镁合金废料生产国标镁合金锭的方法，其特征在于：所述再次 高压清洗的清洗液温度为40～70℃。
  24. 如权利要求9所述的基于镁合金废料生产国标镁合金锭的方法，其特征在于：所述再次高压清洗的清洗时间为5～10min。
  25. 如权利要求7所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤a4的具体操作为：将步骤a3所得镁合金废料放入酸洗池中进行酸洗。
  26. 如权利要求25所述的基于镁合金废料生产国标镁合金锭的方法，其特征在于：所述酸洗的酸洗液pH值为1～3，酸洗时间为30～90s。
  27. 如权利要求25所述的基于镁合金废料生产国标镁合金锭的方法，其特征在于：所述酸洗的酸洗液为盐酸、硝酸、硫酸或草酸溶液中的一种或以上的混合液。
  28. 如权利要求7所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤a5的具体操作为：用水将步骤a4所得镁合金废料表面残留的酸液及杂质除去。
  29. 如权利要求28所述的基于镁合金废料生产国标镁合金锭的方法，其特征在于：步骤a5采用漂洗法或喷淋法。
  30. 如权利要求7所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤a6的具体操作为：将步骤a5所得镁合金废料表面残留的水分除去。
  31. 如权利要求8所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤a7的具体操作为：将步骤a6所得镁合金废料中的不干净废料及非镁料分选出来，从而得到干净废料。
  32. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤b包括将步骤a所得的镁合金废料进行预热、熔融、检测有害元素、精炼、合金化、捞渣和控温静置，分为以下步骤：
    步骤b1：将步骤a所得镁合金废料进行预热；
    步骤b2：将步骤b1所得镁合金废料加热至熔融；
    步骤b3：检测步骤b2所得的镁合金液中各有害元素的具体含量，根据其具体含量选择是否制备国标镁合金锭；
    步骤b4：将步骤b3检测所得用于制备国标镁合金锭的镁合金液进行精炼；
    步骤b5：将步骤b4所得镁合金液进行合金化；
    步骤b6：检测步骤b5所得镁合金液中各金属元素的具体含量；
    步骤b7：分析步骤b6检测的除元素铁外的各金属元素的具体含量是否达标：若达标，进行下一步骤，若不达标，重复进行步骤b5和步骤b6至达标；
    步骤b8：将步骤b7分析得到的达标镁合金液进行捞渣；
    步骤b9：对步骤b8所得镁合金液进行控温、静置；
    步骤b10：检测并分析步骤b9所得镁合金液的元素铁的具体含量是否达标，达标后可进入步骤c。
  33. 如权利要求32所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤b中对镁合金液合金化过程的同时进行再次精炼。
  34. 如权利要求32所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤b6采用铸造镁合金锭GB/T 19078-2003为准检测镁合金液中各金属元素是否达标。
  35. 如权利要求32所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤b4的具体操作为：将加热至熔融的镁合金废料送入熔炼炉中，均匀加入精炼剂，搅拌，搅拌过程中采用精炼剂进行覆盖灭火。
  36. 如权利要求32所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤b5的具体操作为：将步骤b4所得镁合金液取样分析，根据分析结果确定各合金元素加入量，而后向步骤b4所得镁合金液加入合金原料，在合金原料熔融过程中均匀加入的精炼剂，搅拌，搅拌过程中采用精炼剂进行覆盖灭火。
  37. 如权利要求35或36所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤b4或b5中少量多次加入精炼剂，总添加量为15～25kg/t。
  38. 如权利要求35或36所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤b4或b5中精炼时间为15～30min。
  39. 如权利要求35或36所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述精炼过程中全程搅拌。
  40. 如权利要求35所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤b4精炼温度为710～730℃。
  41. 如权利要求36所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：步骤b5精炼温度为720～740℃。
  42. 如权利要求32所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤b5进行合金化时各金属元素的选用标准如下：
    Mg：一级及以上镁锭；
    Al：一级及以上铝锭；
    Zn：一级及以上锌锭；
    Mn：高纯Al-Mn合金、纯度大于99.8％的金属锰粉、或纯度大于99.8％的无水氯化锰中 一种；
    Be：高纯Al-Be合金。
  43. 如权利要求42所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：合金元素的加入顺序为：择需依次加入Mn、Al和Zn、Mg，最后加入Be。
  44. 如权利要求32所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述控温为将温度降至640±5℃后立即升温至660～670℃。
  45. 如权利要求1所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤c包括以下步骤：
    步骤c1：将锭模预热，并在锭模内表面均匀涂覆一层脱模涂料；
    步骤c2：对浇铸泵及浇铸管道进行预热；
    步骤c3：连接浇铸泵及管道，开动浇铸机，开始浇铸。
  46. 如权利要求45所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述预热温度为150～220℃。
  47. 如权利要求45所述的基于镁合金废料生产国标镁合金锭的方法，其特征是：所述浇注温度为640～670℃。
  48. 如权利要求45所述的基于镁合金废料生产国标镁合金锭的方法，其特征是，步骤c还包括步骤c4：对步骤c3所得镁合金锭进行抛光、打码及打包。
PCT/CN2015/074840 2015-02-16 2015-03-23 基于镁合金废料生产国标镁合金锭的方法 WO2016131206A1 (zh)

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CN110564966A (zh) * 2019-09-06 2019-12-13 山西中城天朗环保工程有限公司 一种废旧镁合金手机及笔记本电脑外壳的回收处理方法

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