84results about How to "Low rare earth content" patented technology

The invention provides a Zr based amorphous alloy and a manufacturing method thereof. The components of the Zr based amorphous alloy accord with the following chemical formula (I): ZraCubAlcMdRe (I), wherein M represents one or more of Ni, Fe, Co, Mn, Cr, Ti, Hf, Nb, Be, Si and Ca, R represents one or more of Sc, Y and Er, a, b, c, d and e are atomic percentages, a is greater than or equal to 40 and smaller than or equal to 70, b is greater than or equal to 15 and smaller than or equal to 35, c is greater than or equal to 5 and smaller than or equal to 15, d is greater than or equal to 5 and smaller than or equal to 15, e is greater than 0 and smaller than 0.3, and a+b+c+d+e=100. The manufacturing method of the amorphous alloy comprises the steps of: a) weighing metal raw materials containing Zr, Al, Cu, M and R respectively according to composition of the chemical formula (I) and conducting mixing to obtain a mixed material; b) placing the mixed material in a smelting furnace to undergo smelting so as to obtain a melt, with the burning loss amount of the R element being 5%-100% in terms of atomic percentage; and c) subjecting the melt to casting, thus obtaining the Zr based amorphous alloy. According to the manufacturing method, the dosages of rare earth elements are significantly reduced, and the amorphous characteristics and mechanical properties of the amorphous alloy are ensured.

The invention discloses chemical compositions of ferrite ductile iron used at low temperature and a manufacturing method of the ferrite ductile iron, determines the range of the chemical compositions of the ferrite ductile iron used at low temperature being minus 40 DEG C and provides a quality standard for the production of qualified and stable ductile iron workpieces. The manufacturing method comprises the steps of adopting pure iron, a carburant and silicon iron as raw materials, synthesizing and melting the raw materials in an electric furnace, conducting spheroidization on the raw materials by utilizing a low-rare-earth spheroidizing agent, and producing the ferrite ductile iron by adopting a combined inoculation method. According to the method, the purity of molten iron is improved stably, and the difficulties of high phosphorus, sulphur, titanium, other imputies and interference elements contents in the molten iron, large fluctuation and instability are solved. According to the method, a novel technical scheme is provided for the production of ferrite ductile iron workpiece which contains small, circular and smooth ductile iron and does not contain cementite and iron phosphide eutectic basically, the ferrite ductile iron can meet the demands of high-performance ferrite ductile iron workpiece in electrical industry, high-speed rail industry and the like, the dependence on imported products can be broken; and the running safety of nuclear power and the high-speed rail can be improved substantially.

The present invention discloses a process for making rare earth (RE) doped optical fibre by using RE oxide coated silica nanoparticles as the precursor materia, more particularly the method of the present invention involves preparation of stable dispersions (sol) of RE oxide coated silica nanoparticles at ambient temperature and applying a thin coating on the inner surface of silica glass tube following dip coating technique or any other conventional methods, of the said silica sol containing suitable dopants selected from Ge, Al, P, etc., the coated tubes were further processed into optical preforms by following MCVD technique and fiberised in desired configuration, the novelty lies in eliminating the step of the formation of porous soot layer at high temperature by CVD process inside a fused silica glass tube for formation of the core and also in the elimination of the incorporation of the rare earth ions into the porous soot layer following the solution doping technique or other conventional methods, the direct addition of RE oxides in the sol eliminates the formation of microcrystalites and clusters of rare earth ions and prevents change in composition including variation of RE concentration in the core which results in increase in the reproducibility and reliability of the process to a great extent, further the addition of Ge(OET)4 at ambient temperature in the silica sol reduces the quantity of GeCl4 which is required at high temperature to achieve the desired Numerical Aperture.

The invention relates to a Pr/Nd-based two-phase nano-composite permanent magnet material and a method for the preparation of the block body thereof. The invention comprises the composing general formula of the two-phase nano-composite permanent magnet material: a (Pr, Nd)-Fe-R-Ti-QB system, wherein Pr and Nd are main rare earth components in hard magnetic phase (Pr, Nd)2Fe14B base material; R is one or more than two of Nb, Dy, Tb and Ga; Q is one or more than two of V, Mo, Zr, W and Au; the molar fraction is as follows: x is more than or equal to 4 and less than or equal to 11, y is more than or equal to 0.1 and less than or equal to 3, z is more than or equal to 0.1 and less than or equal to 4, m is more than or equal to 0 and less than or equal to 2, n is more than or equal to 6 and less than or equal to 10, w is more than or equal to 20 and less than or equal to 80, and the balance being Fe. The preparation of the block body (Pr, Nd) 2Fe14B/Alpha-Fe comprises the following steps of (1) smelting master alloy; (2) fast quenching of thin strips; (3) preparing the block body by ultra-high heat pressing, in which the thin strip alloy is put in a graphite mold and then is placed in an ultra-high pressure device, and is sintered for 1 to 30min when the temperature is heated to between 500 and 1000 DEG C at 10-50 DEG C/min, under the pressure intensity of between 1 and 12 GPa and Ar gas protective environment. The Pr/Nd-based two-phase nano-composite permanent magnet material has the advantages of low-content rare earth, low cost, good anti-saturation effect, and the like; the magnetic energy is more than 180 kJ/m3, and the density is more than 74.5 g/cm3.

The invention discloses a high-coercivity sintered R-T-B permanent magnet material and a manufacturing method therefor. The manufacturing method comprises the following steps of A, preparing spherical powder comprising heavy rare earth elements; and B, coating an R-T-B series permanent magnet material manufactured by a normal process with the spherical powder comprising heavy rare earth elements in a laser coating mechanism. By virtue of the manufacturing method for the high-coercivity R-T-B series permanent magnet material provided by the invention, the magnet coercivity can be remarkably improved without influencing remanence, and meanwhile, the usage amount of the heavy rare earth elements is obviously lowered.

The invention makes public a kind of composite nanometer Fe3B/R2Fe14B permanent magnetism powder by high-energy gas atomizing and the method of making it. Transform the alloy fluid, whose atomic composition formulary is Rx(Fel-wCow)100-x-y-xByTz, into ball powder by high-energy gas atomizing. Then dispose it and get composite nanometer Fe3B/R2Fe14B powder based on Fe3B by hot crystallization. The R is at least one component as following: Nd, Pr, Dy, and Tb. The T is at least one of the following components: Zr, Nb, Cr, Ga, Ti, V and Si. And the proportion should be:3.0<=x<=6.0,8<=y<=22,0<=z<=5,0<=w<=0.5. The powder made by this method has advantages such as glaze, ball shape, good fluidity and low cost, and is especially fit for adhesive binding magnet by injection molding.

The invention provides an anisotropic nano-crystalline composite permanent magnetic material and a preparation method thereof. According to the technical solution provided by the invention, a rare earth high-positive-component ingredient is prepared into an anisotropic nano-crystalline magnet through hot pressing/thermal deformation; the anisotropic nano-crystalline magnet is crushed into flaky anisotropic Nd2Fe14B crystal grains; after a rare earth enriched phase is removed, soft magnetic Fe or FeCo is coated on the surfaces of the anisotropic R2Fe14B flaky crystal grains; and then, composite particles are prepared into the full-density bulk anisotropic nano composite magnet through a hot pressing method. The nano-crystalline composite magnet obtained by the invention has high orientation; the defect of incapability of realizing high orientation due to shortage of a neodymium-enriched phase existing in the conventional low-positive-component ingredient is overcome; and the material includes a nano-scale soft and hard magnetic phase, and has high maximum magnetic energy product, high residual magnetism and high intrinsic coercive force.

The invention relates to a wastewater treatment method during the rare-earth hydrometallurgy process, which obtains products that can be used as the material for smelting rare-earth silicoferrite. The method comprises the steps as follows: the rare-earth is acid-dipped, the slurry is stirred and mixed after being added with water; salt solution containing metal ions is added; fluorine-containing waste alkaline water is added in the mixture to form fluoride and hydroxide precipitate, and the addition amount is controlled according to the precipitated metal ion amount that is 10wt percent to 95wt percent; other precipitators are added in sequentially to precipitate the metal ions fully; water is added for washing until the pH value ranges from 7 to 8; solid is dried and dewatered at the temperature that ranges form 110 to 600 DEG C after solid-liquid separation; products can be used as the material for smelting the rare-earth silicoferrite after dehydration. In the waste water discharged in wastewater treatment method, the content of fluorine ion is less than 10mg/L, the pH value ranges from 8 to 9, and the waste water is neutral.

The invention discloses a method for preparing a sintered neodymium iron boron permanent magnet material with high coercive force and high corrosion resistance, and belongs to the technical field of a magnetic material. The method comprises the steps of adding dysprosium zinc nano powder of which the mean grain size is 1-10 microns to neodymium iron boron powder with the grain size of 3-5 microns and evenly mixing, wherein the adding amount is 0.3-3.0%, and then orienting, pressing and molding in 1.8T magnetic field; putting in a vacuum sintering furnace, then heating and sintering at 1000-1100 DEG C for 3-5 hours, and finally carrying out thermal treatment by two levels, wherein the primary thermal treatment temperature is 850-950 DEG C; the time is 1-3 hours; the secondary thermal treatment temperature is 460-600 DEG C, and the time is 1-3 hours, finally obtaining the sintered neodymium iron boron permanent magnet material with high coercive force and high corrosion resistance. The corrosion resistance of the magnetic body is greatly improved when the coercive force of the magnetic body is obviously improved, and the rare earth content is also reduced.

The invention discloses a permanent magnet synchronous motor anti-demagnetization control method which comprises the following steps: first, detecting motor speed and motor phase current, second, if the motor speed is less than the maximum speed of revolution of track before detect percent (TBD%), a system becomes invalid and detects the motor phase current to be over a threshold value, and a controller controls six switching tubes of a three phase permanent magnet synchronous motor to open, third, after n plurality of seconds, entering a next three insulated gate bipolar transistor (IGBT) short circuit module of the three phase permanent magnet synchronous motor, three switching tubes on the three phase permanent magnet synchronous motor keep opening, and the next three switching tubes of the three phase permanent magnet synchronous motor are controlled. According to the permanent magnet synchronous motor anti-demagnetization control method, when normal rotate speed operation of the motor is shifted into the next three IGBT short circuit pattern of the three phase permanent magnet synchronous, an instantaneous peak value large current produced according to an original method is reduced, and the risk of motor permanent magnet steel demagnetization is prevented or reduced. So when the motor is designed, magnetic circuit design can be carried out based on the reduced instantaneous peak value current, magnet steel with low coercivity is chosen, rare earth content is reduced, and the purpose of reducing cost is achieved.

The invention relates to a method for separating and recovering iron, rare earth and fluorine from rare-earth-contained tailings after beneficiating iron. The method comprises the steps that the rare-earth-contained tailings after beneficiating iron, an additive and pulverized coal are subjected to roasting, ball-milling and magnetically separating after being mixed, briquetted or pelletized to obtain magnetic iron ore concentrate and magnetic tailings; hydrochloric acid is added into the magnetic tailings for leaching, and rare earth chloride leaching liquid and leaching residues rich in calcium fluoride are obtained after filtering; and water is added into the leaching residues to be stirred to form ore pulp, water glass, sodium oleate and terpenic oil are added to obtain rougher concentrate and rougher tailings, and after concentration, calcium fluoride concentrate and total tailings containing a mixture of silicate and a small amount of calcium fluoride are obtained. The method disclosed by the invention has the characteristics of good separation effect, high recovery rate of iron and rare earth, low production cost, large treatment capacity, environmental friendliness and the like, and is a process method relating to the fields of non-blast furnace ironmaking, hydrometallurgy, mineral processing technologies and comprehensive utilization of resources.

The invention discloses a method for improving the coercivity of sintered neodymium iron boron composite magnets, and belongs to the field of preparation of rare earth permanent magnetic materials. The methodoptimizes the composition of the Nd-Fe-B alloy and the Dy-Fe-B alloy, appropriately reduces the content of Nd in the Nd-Fe-B alloy, andincreases the content of Dy content in the Dy-Fe-B alloy.Since the content of the Nd elementin the Nd-Fe-B alloy is small, the diffusion degree of the Nd element decreases in the sintering process, so the Dy in the Dy-Fe-B alloy is less likely to be replaced by the Nd element, the anisotropy field of Dy-Fe-B phase high magnetic crystalis maintained, and the coercivity of magnet with small addition amount of Dy-Fe-B alloy powder can be improved significantly. The method can also reduce the amount of rare earth and Dy elements, and reduce the cost of raw materials while improving the magnetic performance.

The invention relates to a heat-resistant magnesium alloy heat treatment method, suitable processing objects being magnesium alloy materials, cast ingots and castings containing two or more than two rare earth elements. A preparation process includes homogenization, solid solution treatment and aging. The heat-resistant magnesium alloy heat treatment method can greatly improve the mechanical properties of the multi-component rare earth magnesium alloy with low rare earth content, can also solve processes and technical problems such as deformation, breaking, and structure uniformity during a heat treatment process of large magnesium alloy ingot blanks and medium and large complex thin-wall magnesium alloy castings, satisfies practical application of scientific research and industrial production of magnesium alloy materials, and has outstanding significance to improve the performance index of high-end magnesium alloy materials and castings in China and enrich the processing technology ofhigh-performance magnesium alloy materials, and especially in the field of special magnesium alloy heat treatment.

The invention provides neodymium-iron-boron magnet powder. A neodymium-rich phase in the powder granules generates neodymium hydride in a hydrogen absorption smashing stage; then in the subsequent air flow powder grinding stage, the powder granules obtain quite high resistance to oxidation, and a neodymium-iron-boron magnet with low rare earth content, low cost and high performance can be prepared more easily; the neodymium-iron-boron granules comprising the hydride are high in brittleness, and the air flow powder grinding efficiency is improved by 50% or even 100% compared with that of the conventional process; the prepared powder granule dimensions can be reduced to be smaller than 3[mu]m, which is a quite significant condition for preparing a sintered neodymium-iron-boron magnet with high coercivity and high thermal stability; the powder granules are subjected to dehydrogenation, so that the orientation degree of the powder granules in an orientation pressing process is improved, residual magnetism of the magnet is improved, generation of internal cracks of the magnet can be effectively suppressed, and the mechanical performance of the sintered neodymium-iron-boron magnet is improved; and by effectively combining the dehydrogenation process with a fine powder mixing process, the process is simplified, the powder production efficiency is improved and the cost is lowered.

The invention relates to a rare earth Al-Ca-Fe alloy for rare earth micro-treated steel and a preparation method thereof, and belongs to the technical field of ferroalloys. The rare earth Al-Ca-Fe alloy comprises, by weight, 28-65% of aluminum, 0.5-5% of calcium, 0.1-0.99% of rare earth, less than0.05% of impurity element carbon, less than0.4% of silicon, 0.02% of sulfur, less than0.02% of phosphor, less than1% of inevitable impurities and the balance ferrum. According to the preparation method, the finished alloy which meets requirements is prepared by utilizing pure aluminum ingots, rare earth, calcium metal and low-carbon high-quality scrap steel through a three-step method smelting process of an induction furnace. The rare earth Al-Ca-Fe alloy and the preparation method have the advantages that consumption of rare earth is reduced and the cost is reduced.

The invention belongs to the technical field of rare earth waste resource recycling, and particularly relates to a method for recycling rare-earth elements from neodymium iron boron waste with high silicon content and low rare earth content. The method is characterized in that the neodymium iron boron waste with high silicon content and low rare earth content is mixed with neodymium iron boron waste with high rare earth content as well as fluffy powder, so that a pre-roasting process can be normally performed, and performing of a follow-up process is facilitated, and therefore, recycling for rare-earth elements with high silicon content and low rare earth content is realized. The method is suitable for a process for recycling rare earth from neodymium iron boron waste with high silicon content and low rare earth content, can effectively recycle praseodymium-neodymium oxide, dysprosium oxide, gadolinium oxide and terbium oxide, has a recovery rate of 93%, 95%, 90% and 91%, and developsa novel way for comprehensively treating and recycling rare earth elements from neodymium iron boron waste, so that wider resources are sufficiently recycled.

The invention relates to the technical field of marine diesel engines, and particularly relates to a smelting method for the cylinder cover of a marine diesel engine. The smelting method comprises the following steps of: proportioning, smelting original molten iron, performing spheroidization treatment, performing primary inoculation treatment, performing secondary inoculation treatment, and pouring. During smelting, a certain amount (about 0.25%) of Mn is added, so as to ensure that the content of pearlites meets technical requirements while ensuring the strength of castings; 1.3-1.8% of T-1 type spheroidizing agent is used for performing inoculation twice, and stream inoculation is performed during the secondary inoculation, so that the spheroidization rate can be increased, the spheroidization degeneration of the castings can be prevented, and the inoculation effect can be ensured; and moreover, the T-1 type spheroidizing agent is a heavy-rare-earth ferrite type spheroidizing agent capable of effectively stabilizing ferrite, ensuring the low content of rare earth, and greatly reducing the shrinkage trend of the castings.

The invention discloses a zinc-aluminum-magnesium alloy wire containing rare earth, and a preparation method and application thereof. The zinc-aluminum-magnesium alloy wire is prepared from the following components: 15 to 40 percent of aluminum, 0.2 to 4.0 percent of magnesium, 0.02 to 0.2 percent of rare earth elements, i.e. cerium and erbium, not larger than 0.025 percent of impurities, and the balance of zinc, wherein the mass ratio of the two rare earth elements i.e. Ce to Er is 3:7 or 7:3. According to the zinc-aluminum-magnesium alloy wire containing the rare earth provided by the invention, the rare earth elements such as the cerium and the erbium are added, so that the corrosion resistance is improved, meanwhile, the zinc-aluminum-magnesium alloy wire has the advantages of high strength, high hardness, low price and the like, and can replace a traditional zinc wire so as to be used for the fields such as spraying anticorrosion engineering, and a zinc-aluminum-magnesium alloy heat coating has an excellent adhesive force, favorable physical and mechanical properties and a corrosion resisting property. The average annual corrosion rate of the zinc-aluminum-magnesium alloy heat coating is larger than the average annual corrosion rates of a heat spraying zinc coating, a zinc aluminum alloy coating, a zinc aluminum pseudo alloy coating and the like, and an anodic protection effect of the zinc-aluminum-magnesium alloy heat coating is remarkably improved compared with the anodic protection effects of aluminum and other aluminum alloy heat spraying metal layers; the whole wire material processing and manufacturing process is simple and convenient, and the cost is lower.