38results about How to "Raise the yield of rare earth" patented technology

The invention relates to a method for adding rare earth into RH refining furnace. The method is characterized in that rare earth lanthanum ferroalloy is added into a RH refining station vacuum feeding bin; molten steel, which satisfies the condition that total oxygen content T.O is less than or equal to 0.002 wt%, active oxygen content a [O] is less than or equal to 0.0005 wt% and [S] content is less than or equal to 0.005 wt% in steel, undergoes vacuum treatment at the RH refining station for 10 min or more than 10 min; and according to the calculated addition of rare earth, rare earth lanthanum ferroalloy is added into a vacuum chamber from the vacuum feeding bin, wherein the addition of the rare earth is controlled within the range of 0.005-0.015 wt%. The invention has the following advantages: by the adoption of the method, the yielding rate of rare earth is high and stable; continuous casting production is smooth; rare earth in steel is uniformly distributed; by the adoption of the rare earth lanthanum ferroalloy, performance of steel is substantially improved; the method requires low cost and is simple to operate; metallurgical effects of rare earth microalloyed steel are obvious; and the method has an extensive popularization and application prospect.

The invention discloses a steel containing rare earth element and a producing method of slab continuous casting. The steel comprises the elements of Re, C, Si, Cr, Ni, and N according to a certain ratio, and the balance of iron and inevitable impurity; the production method comprises a ladle furnace refining process and a continuous casting operation; wherein, in the ladle furnace refining process, feeding metal Ca wire before rare earth is added in molten steel, then feeding rare earth metal wires, simultaneously passing the rare earth metal wires through the surface of slag, feeding the metal Ca wires again, controlling the weak stirring time of ladle furnace refining and slag interfacial fluctuation area; and in the continuous casting process, controlling the super-heated rate of molten steel in a tundish at 35-65 DEG C, and controlling the inserting depth of an port of a continuous casting crystallizer at 100-135 mm. Compared with the prior art, the method has the advantages of high rare earth yielding rate, and good continuous casting surface and center quality, impurity in the steel is effectively removed, and rare earth yielding rate is stable.

The invention relates to a self recycling method of waste water in rare earth carbonate precipitation, which belongs to the field of rare earth hydrometallurgy. The method comprises the following steps: part of mother liquor, which is generated in the rare earth carbonate precipitation production process, is directly transmitted into a rare earth carbonate recycling pool to be clarified, and concentrating and crystallization equipment is used for recyling ammonium chloride or sodium chloride; the rest of the mother liquor is transmitted into a mother liquor storage tank, and is used for adjusting the concentration of carbonate precipitation liquor and dissolving the precipitant; the rare earth carbonate precipitate is washed in a reverse flow mode to obtain a first filtrate; the first filtrate and the mother liquor are recycled to the rare earth carbonate precipitation technique to dissolve the precipitant and dilute the liquor; and the residual waste water after recycling is concentrated and crystallized to recycle ammonium chloride or sodium chloride. The precipitation waste water is recycled, thereby reducing waste water discharge amount and the consumption of new water, increasing the concentration of ammonium chloride or sodium chloride in waste water and lowering the energy consumption for concentration and crystallization.

The invention belongs to separation of nonferrous metals and rare earth, and particularly relates to a method for replacement dissolution of rare earth bastnaesite and bastnasite. The technical scheme is that the method comprises the following steps of: performing low-temperature roasting on the bastnaesite and bastnasite at 400 to 500 DEG C; adding chlorhydric acid into the materials after the low-temperature roasting to dissolve out rare earth, and adding non-rare-earth substances which can be combined with fluorine (F) into the mixtures to combine with the F so as to obtain a rare earth chloride solution and solid fluoride, and performing solid-liquid separation; adding sulfuric acid into the obtained solid fluoride to roast and recover hydrofluoric acid; and performing water immersion on rare earth sulfate contained in dry residues after the recovery of the hydrofluoric acid to obtain a rare earth sulfate solution. According to the method, the fluorine ions which are dissolved out when the bastnaesite is dissolved with the chlorhydric acid are not combined with the rare earth, but are combined with other non-rare-earth substances, so that the fluorine cannot be formed into rare earth fluoride to influence the dissolution rate of the rare earth. By adopting the method, a process for defluorination and a process for directed complexation of cerium are not required, the aim of completely dissolving the bastnaesite as much as possible through one step by using the chlorhydric acid is fulfilled, the fluorine is changed into other high-added-value chemical raw materials and the rare earth can be recovered through one step, so that the rare earth recovery rate and the value of rare earth elements are high.

The invention relates to a method for applying baotite mixed carbonate-rare earth precipitation wastewater in precipitation of europium (II) sulfate, belonging to the field of rare earth hydrometallurgy. The method comprises the step of concentrating precipitation wastewater from production of mixed carbonate-rare earth by baking and decomposing rare earth baotite concentrate with concentrated sulfuric acid to obtain a concentrated mixed solution of ammonium sulfate and magnesium sulfate. The obtained concentrated mixed solution is used as a rich europium preparation reagent in europium oxide extraction process from Sm-Eu-Gd enrichment mineral to replace single magnesium sulfate heptahydrate to be used as europium (II) sulfate precipitant, thereby broadening the recycling ranges of precipitation wastewater from production of mixed carbonate-rare earth from rare earth baotite concentrate, lowering the energy consumption in concentration and crystallization of recovered wastewater, saving the production cost, and reducing the resource waste and environmental pollution.

The invention provides a method for leaching calcium and strontium by using low concentration hydrochloric acid to chemically separate Weishan Lake rare earth concentrate. The method comprises the following steps: immersing the Weishan Lake rare earth concentrate in the low concentration hydrochloric acid, and heating the obtained solution to perform a reaction; adding the Weishan Lake rare earthconcentrate to a filtered leachate, heating the obtained solution to perform a reaction, carrying out solid-liquid separation, discharging the obtained liquid, and reusing the obtained solid phase. The grade of the Weishan Lake rare earth concentrate is improved to 50% from 40%, 90% of calcium carbonate and 85% of strontium carbonate in the Weishan Lake rare earth concentrate are efficiently leached out, the rare earth loss rate of below 1% is ensured, a discharged acid leaching waste liquid only contains calcium chloride, strontium chloride and a small amount of iron chloride, and wastewatertreatment is easy.

The invention discloses a praseodymium-neodymium-iron alloy. The praseodymium-neodymium-iron alloy comprises 0-95wt% of praseodymium and neodymium and the balance iron and inevitable impurities of which the total content is less than 0.5wt%, wherein the content of oxygen is less than or equal to 0.01wt%, the content of carbon is less than or equal to 0.01wt%, the content of phosphorus is less than or equal to 0.01wt%, and the content of sulfur is less than or equal to 0.005wt%. The invention further discloses a preparation method of the praseodymium-neodymium-iron alloy. The praseodymium-neodymium-iron alloy prepared through the method is uniform in composition, small in segregation, low in impurity content, high in rare-earth yield, low in cost, and free of pollution; and the praseodymium-neodymium-iron alloy is high in rare-earth yield and remarkable in effect when applied to rare-earth steel, and is suitable for large-scale industrial production.

The invention discloses a lanthanum-cerium-iron alloy used for producing rare earth steel. The content of lanthanum-cerium is 0-95wt%, and the balance is iron and unavoidable impurities less than 0.5wt%. Oxygen≤0.01wt%. Carbon≤0.01wt%, phosphorus≤0.01wt%, sulfur≤0.005wt%. The invention also discloses a preparation method of the lanthanum-cerium-iron alloy used for producing rare earth steel. The lanthanum-cerium-iron alloy prepared by the invention has uniform composition, small segregation, low impurity content, high rare earth yield, low cost and no pollution, and is applied to rare earth steel with high rare earth yield and remarkable effect, and is suitable for large-scale industrial production.

The invention discloses a yttrium-ferrous alloy, which is prepared from the following components in percent by weight: 0 to 95 percent of yttrium, and the balance ferrous and inevitable impurities with the total amount being less than 0.5 percent, wherein oxygen is less than or equal to 0.01 percent by weight, carbon is less than or equal to 0.01 percent by weight, phosphorus is less than or equal to 0.01 percent by weight, and sulfur is less than or equal to 0.005 percent by weight. The invention further discloses a preparation method of the yttrium-ferrous alloy. The yttrium-ferrous alloy prepared through the invention is uniform in component, small in segregation, low in impurity content, high in rare earth yield, low in cost and free of pollution, is high in rare earth yield and remarkable in effect when being applied in rare earth steel, and is suitable for large-scale industrial production.

The invention discloses a method for preparing high-purity metal ytterbium through one-time continuous reduction distillation. The method comprises the steps that a vacuum smelting furnace is adopted,a basic raw material pressing block is placed in a metal crucible, and titanium and molybdenum-manufactured double-plug plates are arranged at different temperature transition sections of a distillation system; a combustion chamber of the vacuum smelting furnace is vacuumized to be 10 Pa or below, current delivery and heating are carried out, the heating rate, and thermal insulation time are controlled for heating, metal lanthanum is used for thermal reduction on high-purity ytterbium oxide, a generated metal ytterbium is condensed in a receiver after being distilled by the double-plug plates, a diffusion pump is closed after distillation is completed, argon is filled, and cooling is conducted to a normal temperature according to the set cooling speed and time. The invention further discloses the vacuum smelting furnace. According to the method, stable operation of a distillation process is ensured, the metal ytterbium is low in overflow rate, the rare earth yield is high, impurity entrainment is effectively removed, and lanthanum impurities in the metal ytterbium are greatly reduced.

The invention relates to a method for preparing a low magnesium calcium sulfate dihydrate byproduct from a sulfuric acid rare earth solution. The method includes steps: using the sulfuric acid rare earth solution generated during the sulfuric acid smelting rare earth ore concentrate separation process as raw material, using calcium hydroxide as a neutralizing agent, and by controlling conditions such as concentration of calcium hydroxide grouting liquid, REO (rare earth oxide) concentration in the sulfuric acid rare earth solution, reaction time, reaction temperature, neutralization of PH (potential of hydrogen) value and aging mode, preparing the byproduct of CaSO4.2H2O which meets use requirements in industry of cement, building material, chemical engineering and the like under the condition that the yield of rear earth is not reduced and supply of qualified sulfuric acid rare earth feed liquid for extraction separation of downstream rear earth smelting is guaranteed. Additionally, the quality of the CaSO4.2H2O meets following formulas: m(CaO)>=30.9%, and m(MgO)<=0.05%. The whole process of the method achieves low cost of industrial production, and builds a firm foundation for green environment-friendly production and circular economy usage.

The invention provides a rare earth calcium core-spun yarn. The rare earth calcium core-spun yarn comprises a rare earth calcium core-spun material, a trapping agent and a metal shell protection tube. According to the method, the effect and the purpose that the molten steel is subjected to rare earth alloying by directly using the rare earth oxide without a special reduction smelting link by utilizing the excess (or surplus) temperature of the molten steel are achieved; the metal silicon is adopted as a reducing agent to convert rare earth oxide into rare earth metal for alloying, and the metal aluminum is adopted as a reducing agent to reduce calcium oxide into metal calcium (steam), so that the effects of deoxidizing the molten steel, removing inclusions and changing the morphology of the inclusions are achieved. The method has the characteristics of high rare earth yield, low cost, economy, practicability and convenience in large-scale production. The method has great positive significance in reducing the alloying cost of the molten steel, improving the quality of the molten steel, improving the utilization efficiency of the rare earth and saving rare earth resources.

The invention belongs to the technical field of hot work die steel, and discloses modified 4Cr5MoSiV1 hot work die steel and a preparation method thereof.The preparation method comprises the following steps: putting weighed raw materials into vacuum furnace, smelting to molten state, adding reducing agent, smelting at 1450-1550 DEG C, casting under argon protection, and naturally cooling after casting to obtain steel ingot; remelting the steel ingot by using a protective atmosphere electroslag remelting technology, preserving heat at 1250 DEG C, forging and cooling; and carrying out heat preservation at 850 DEG C, and then carrying out segmented furnace cooling to room temperature, so as to obtain the modified 4Cr5MoSiV1 hot work die steel. By adding the rare earth intermediate alloy and utilizing the interaction of all the components, the yield of rare earth in the steel is increased; segregation of alloy elements such as Cr, Mo and V at the grain boundary is reduced, and the purpose of reducing dendritic segregation is achieved; and the as-cast structure of the steel is improved, and the fatigue life and other mechanical properties of the steel are improved.

The invention discloses a method for preparing metal ytterbium by reducing and distilling an ytterbium oxide raw material with high chlorine content. The method comprises the following steps: puttingthe high-purity ytterbium oxide raw material with chlorine content greater than 100 PPM into a metal crucible, transferring the metal crucible into a vacuum heating furnace, gradually heating up the metal crucible to a temperature of 1100-1200 DEG C to perform vacuum roasting in a staged heating-up and heat-preserving way under a sealing environment with vacuum degree lower than 10 Pa; switching off a mechanical pump after completing vacuum roasting, and cooling the metal crucible to the normal temperature; moving the metal crucible out of the vacuum heating furnace, and putting vacuum-roastedhigh-purity ytterbium oxide and lanthanum chip pressure blocks into a vacuum carbon tube furnace to reduce and distill; reducing ytterbium oxide into metal ytterbium by metal lanthanum in a staged heating-up, heat-preserving and cooling way for reducing and distilling under the sealing environment with the vacuum degree lower than 10 Pa, and distilling and condensing the metal ytterbium in a receiver. Cl content in the metal ytterbium obtained by the method is less than 100 PPM, and the rare-earth yield is greatly increased.