127 results about "Calcium handling" patented technology

The silicon steel comprises the following components in percentage by weight: 0 to 0.005 percent of C, 1.3 to 2.8 percent of Si, 0.20 to 0.80 percent of Mn, 0 to 0.05 percent of P, 0.2 to 1.2 percent of Al, less than or equal to 0.005 percent of S, less than or equal to 0.005 percent of O, less than or equal to 0.005 percent of N, less than or equal to 0.003 percent of Nb, less than or equal to 0.003 percent of V, less than or equal to 0.003 percent of Ti, 0.001 to 0.005 percent of Ca, one or two of 0.02 to 0.15 percent of Sb, 0.02 to 0.15 percent of Sn and 0.1 to 0.4 percent of Cu, and the balance of Fe and inevitable impurities. By adding proper trace elements, adopting effective calcium treatment to control inclusions and matching with proper hot rolling, cold rolling and annealing processes, an unnormalized low-iron-loss high-magnetic-induction non-oriented silicon steel product is obtained. The minimum iron loss P15 / 50 of the manufactured non-oriented silicon steel product with the thickness of 0.5 mm is 2.73 w / kg, and the maximum magnetic induction intensity B50 / 50 can reach 1.735 T; the minimum iron loss P15 / 50 of the series with the thickness of 0.35 mm is 2.25 w / kg, and the maximum magnetic induction intensity B50 / 50 can reach 1.718 T.

The invention belongs to the technical field of metallurgical steelmaking production, and particularly relates to a control method for B-type inclusions in ultralow-sulfur steel. The production process comprises the steps of molten iron treatment, converter smelting, LF refining, RH refining, calcium treatment and soft blowing, continuous casting and hot rolling, and is characterized in that in the calcium treatment and soft blowing process, after RH is finished, a calcium line is fed for calcium treatment, the content of calcium in molten steel is reduced, and the content of calcium in tundish molten steel is controlled to be 5-10 ppm; the total air volume of soft blowing is controlled to be 80-180 NL / min, and the soft blowing time is controlled to be 7-12 min. According to the method, large-size CaO-Al2O3 series and CaS-CaO series inclusions do not exist in the molten steel, the large-size strip-string-shaped inclusions are obviously improved after hot rolling, and the cleanliness of the molten steel and the product quality are obviously improved; meanwhile, the consumption of calcium lines in the production process is reduced, and the production cost is reduced.

The invention relates to a treatment method and device for resource utilization of desulfurization wastewater in the technical field of desulfurization wastewater treatment, and the device comprises a pretreatment module, a magnesium removal module, a calcium removal module, a nanofiltration salt separation module, a concentration reduction module and a flue evaporation module, the method comprises the steps of pretreatment, magnesium removal treatment, calcium removal treatment, nanofiltration salt separation treatment, evaporative crystallization treatment and the like, heavy metals and suspended solids in the desulfurization wastewater are removed in the pretreatment module, a high-purity magnesium hydroxide product is extracted through the magnesium removal module, after calcium ions are removed in the calcium removal module, salt separation treatment is conducted through the nanofiltration salt separation module, and the high-purity magnesium hydroxide product is obtained. One part of the separated monovalent saline water is recycled, the other part of the separated monovalent saline water is concentrated and reduced by the concentration and reduction module and then enters the flue evaporation module to be evaporated, and the separated divalent saline water is recycled to a desulfurization system. The method has the advantages of simplicity and convenience in operation, economical operation, environment-friendly process and the like, high-purity magnesium hydroxide can be recycled, complete zero emission of the desulfurization high-chlorine wastewater is realized, and the method has a relatively high commercial application value.

The invention discloses a control method for a steelmaking continuous casting process of high-rare-earth-content low-alloy steel, which realizes high cleanliness of steel before rare earth alloying through measures such as converter end point oxygen content control, furnace slag washing, LF (ladle furnace) refining and calcium treatment, effectively improves the yield of rare earth elements, improves the production efficiency and ensures continuous casting. Compared with conventional production, the method has the advantages that the problem of high-content rare earth steel flocculation flow is solved, the yield of rare earth elements in the steel is greatly increased, and the yield of the rare earth elements in the steel can be stably controlled to be 50% or above.

The invention discloses a high-strength steel smelting method for improving the purity of molten steel, which comprises the following steps: (1) carrying out composite desulfurization on lime and magnesium powder in a desulfurization station, and then removing slag to ensure that the sulfur in the back of a converter is less than 150ppm; (2) carrying out desulfurization on the LF by adopting lime and an aluminum deoxidizer until the desulfurization is 20-40ppm; (3) after the molten steel begins to circulate in the RH vacuum chamber, aluminum is added according to the predicted oxygen blowing amount, and oxygen blowing operation is carried out after aluminum adding is finished and stabilization is carried out; (4) 140 + / -10 m seamless pure calcium core-spun yarn is fed, and molten steel is statically stirred for 15-20 min after calcium treatment; (5) performing protective casting during continuous casting, and completely eradicating air suction; and (6) a strong secondary cooling water process is adopted for the thick plate continuous casting billet to accelerate dendritic crystal nucleation in the continuous casting billet, and when the solid-liquid phase rate of the continuous casting billet ranges from 0.2 to 1.0, the center segregation of the continuous casting billet is guaranteed under the heavy pressure of 12 mm. The method has the advantages of improving the purity of the molten steel and improving the center segregation of the continuous casting billet.

The utility model provides an efficient sewage treatment system for high-calcium wastewater, which comprises a biological decalcification unit and a biochemical treatment unit, the bottom of a first anaerobic tank of the biological decalcification unit is communicated with the top of a first anoxic tank, the bottom of the first anoxic tank is communicated with a first aerobic tank, and the first aerobic tank is communicated with a first sedimentation tank; the bottom of a second anaerobic tank in the biochemical treatment unit is communicated with the top of a second anoxic tank, and the bottom of the second anoxic tank is communicated with a second aerobic tank; the first sedimentation tank is communicated with the upper part of the second anaerobic tank. The sewage treatment system is based on two-stage A2O, most of calcium ions in water are removed through first-stage A2O, decalcification treatment is carried out, a basis is provided for COD removal, denitrification and other biochemistry through second-stage A2O, the biological treatment effect of high-calcium wastewater is improved, meanwhile, sludge is screened and concentrated through the cyclone device, residual sludge is subjected to resourceful treatment, and the treatment effect of the high-calcium wastewater is improved. And the effects of reducing the cost, improving the efficiency and recycling resources are achieved.

The present application relates to high-temperature alloy smelting technical field, specifically relates to a kind of high-aluminum titanium cast nickel-based high-temperature alloy purification smelting method.The pure smelting method, step one, low calcium nickel alloy preparation;Step two, pure smelting: batching and furnace charging, melting period, refining period, alloying period, calcium treatment purification period and casting period;Pure smelting process is carried out in vacuum induction melting furnace, 2 / 3 low calcium nickel alloy is directly loaded into magnesium oxide crucible when furnace charging, and the remaining 1 / 3 low calcium nickel alloy is added in calcium treatment purification period.The present application prepares a kind of component accurately controllable "low calcium nickel alloy" as master alloy by pre-preparation, is added in key smelting stage, solves the problem of calcium element direct addition, realizes the deep deoxidation denitrogenation desulfurization of alloy melt, significantly reduces the oxygen, nitrogen, sulfur impurity content in alloy, to improve the purity and comprehensive mechanical properties of alloy.

The invention discloses a method for improving castability of aluminum-containing steel in a continuous casting process, which comprises the following steps of: S1, controlling components of molten steel, and accurately controlling the content of acid-soluble aluminum in molten steel of a continuous casting ladle to be 0.020-0.060% according to mass percent; s2, calcium treatment is conducted on the molten steel, and the calcium-aluminum ratio is controlled to range from 0.10 to 0.15; s3, continuous casting process control is conducted, specifically, the superheat degree of tundish molten steel is stably controlled to range from 15 DEG C to 30 DEG C, meanwhile, constant pulling speed operation is adopted, and the pulling speed fluctuation range is controlled within + / -0.1 m / min; and S4, the content of SiO in the casting powder is reduced to be smaller than or equal to 20%, and meanwhile, the alkalinity R of the casting powder is 1.5-2.0. The continuous casting process is ensured to be smooth, nozzle nodulation and casting blank surface defects are effectively prevented, and the production efficiency and the product quality are remarkably improved.

The invention discloses a production method for reducing flaw detection defects of wind power gear steel, and belongs to the technical field of ferrous metallurgy. According to the method, an electric furnace-LF-VD-continuous casting process route is adopted, the mass fraction of an aluminum element Al in molten steel is controlled to be not lower than 0.018% in the LF refining process, and the mass fraction of [Al] is controlled to be higher than 0.010% all the time in the VD vacuum treatment process. And after VD vacuum breaking, aluminum is supplemented in time, the mass fraction of Al is increased to 0.015%-0.020%, calcium treatment is reasonably carried out, and the mass fraction of Ca in molten steel is controlled to be 0.0006%-0.0009%. By accurately controlling the component change of the molten steel in the VD process, the formation of CaO-MgO-Al2O3-SiO2 inclusions with high SiO2 content is effectively inhibited, the large-size ultrasonic flaw detection defects in the wind power gear steel are remarkably reduced, and the internal quality of the steel is improved. The method is simple in process and remarkable in effect, and has a good industrial application prospect.

The invention discloses a refining calcium-free treatment process, and belongs to the technical field of refining and smelting of high-carbon aluminum-containing steel. According to the method, various smelting parameters of the whole steelmaking process are adjusted, sulfur entering a converter is guaranteed in a desulfurization area, tapping carbon, tapping temperature, in-place refining component hit rate, deoxidation degree and tapping phosphorus difference are guaranteed in a converter area, refining treatment time, white slag protection time and soft blowing time are guaranteed in a refining area, the content of Al2O3 in molten steel is reduced, the purity of the molten steel is guaranteed, and the quality of the molten steel is improved. Molten steel calcium-free treatment is achieved, and the quality of molten steel is improved.

The invention provides an LF-RH duplex process calcium treatment method, and belongs to the technical field of steelmaking production in the ferrous metallurgy industry. The method comprises the following steps that after molten iron is pre-desulfurized, converter smelting, LF refining and RH refining are sequentially carried out, in the RH refining process, high-calcium wires are fed for calcification treatment, and the calcium treatment process is completed. Compared with the prior art, the LF-RH duplex process calcium treatment method provided by the invention adopts specific process steps and conditions to realize better overall interaction: by determining the optimal calcium treatment opportunity, the inclusion control level of the molten steel is improved, and clean production of the molten steel is realized. Experimental results show that calcium treatment is carried out in the RH procedure, the inclusion level in the molten steel is reduced, stable production of high-quality steel is achieved, under the condition that the hydrogen content is basically consistent, the effect of reducing the inclusion in the molten steel is good, and the cleanliness of the molten steel can be improved.

The application discloses a slag washing desulfurization calcium treatment process, which comprises the following steps: (1) detecting calcium wire for calcium treatment: the method comprises sample preparation, dissection and analysis; the filling of reduced iron powder and the bonding state of calcium particles, the pressure pit of internal iron sheet, the particle size of iron powder and the observation and data information comparison of the weight of the two kinds of powder should be observed from the cross section and the section; the metallurgical effect of calcium treatment is preliminarily judged according to the influencing factors; (2) strictly controlling the particle size of reduced iron powder and the suitable ratio of calcium particles and reduced iron powder, and selecting calcium wire meeting the requirements to be put into the slag washing desulfurization process; the calcium wire selected by the above detection method can make the wire feeding speed stable at 4-4.5 m / s, so that the wire feeding speed is not reduced due to flash explosion and spatter, and the stability of production is ensured.

The invention provides a control method for a multi-mode continuous casting and rolling production line strip steel surface slag inclusion defect, and belongs to the field of steel preparation. The method comprises the following steps: carrying out desulfurization treatment on blast furnace molten iron to obtain desulfurized molten iron with set sulfur content; the desulfurized molten iron is subjected to converter smelting, and converter molten steel with the set oxygen content is obtained; the converter molten steel is subjected to LF refining, and the molten steel is subjected to calcium treatment and soft blowing treatment for a set time before LF refining is carried out, so that refined molten steel with the set calcium content is obtained; and the refined molten steel is subjected to continuous casting, the pulling speed of a casting machine is increased in a mode dividing mode at the pulling speed rising stage of continuous casting, and a continuous casting blank is obtained. Through narrow-interval control on smelting molten steel end point oxygen, refining top slag oxidability is reduced, the outbound calcium content and soft blowing time are guaranteed, and through a staged acceleration strategy, the liquid level fluctuation is within + / -3mm, and the multi-mode continuous casting and rolling production line strip steel surface inclusion defect is successfully controlled at the optimal level.

The present invention discloses a method for treating inclusions in modified steel with rare earth cerium during refining. This method belongs to the field of iron and steel metallurgy and solves the technical problem of unstable effects of calcium treatment during existing steelmaking and refining. The method comprises the following steps: step S1, smelting in a converter or electric furnace; step S2, performing aluminum deoxidation and alloying in a ladle during tapping from the converter or electric furnace; step S3, refining in a LF furnace or LF furnace to RH furnace, with rare earth cerium treatment performed in the final refining step; and step S4, continuous casting or die casting after refining. The rare earth cerium element yield in the steel of the present invention is over 30%, far exceeding the 5-15% yield of calcium. The rare earth cerium treatment method of the present invention achieves a spherical ratio of inclusions in the steel of over 90%, and the corrosion resistance of the steel is reduced by over 10% compared to the relative corrosion rate of calcium-treated steel.

This invention discloses a method for reducing the refining cost of low-carbon cold heading steel, belonging to the field of iron and steel metallurgical technology. The method includes: recovering molten slag before tapping from the converter; reducing carbon content to below 0.06% in the later stages of smelting; bottom blowing argon after oxygen blowing and measuring oxygen content, dynamically calculating the addition amounts of ferroaluminum and lime; adding ferroaluminum and lime during tapping; adjusting aluminum to 0.050%-0.055% after tapping by feeding aluminum wire; slag breaking and power supply after the molten steel reaches the LF furnace, adding lime at 1.3 times the amount of aluminum added after tapping; raising the temperature to 1600-1605℃ after a second sampling, adding ferromanganese, calculating aluminum loss based on power supply time, and controlling aluminum at 0.035%-0.040%; finally, calcium treatment and soft blowing are performed. This invention achieves low-cost and high-efficiency refining of low-carbon cold heading steel through optimizations such as recovering molten slag, dynamically calculating material addition amounts, moving deoxidation and slag formation forward, reducing material consumption, and replacing large-scale argon agitation for impurity removal.

The invention discloses a TMCP type F-grade marine structural steel plate and a production process thereof, and relates to the technical field of steel production, the TMCP type F-grade marine structural steel plate comprises the following chemical components by mass percentage: 0.03-0.08% of C, 0.10-0.40% of Si, 1.35-1.70% of Mn, less than or equal to 0.012% of P, less than or equal to 0.005% of S, 0.01-0.15% of Ni, 0.008-0.020% of Nb, 0.020-0.040% of Al, and the balance Fe and other inevitable impurities. According to the invention, the LF, VD, calcium treatment and soft blowing processes are adopted to reduce endogenous inclusions generated by molten steel, meanwhile, the continuous casting billet is utilized to improve the metal yield and greatly reduce the production cost, in addition, through the reasonable controlled rolling process, the steel plate has good comprehensive performance, and the production cost is greatly reduced compared with that of normalized F-level steel for the ship body structure.

According to the smelting process, EBT electric arc furnace smelting, LF furnace refining, VD vacuum treatment and continuous casting are adopted, the end point C of an electric arc furnace ranges from 0.08% to 0.25%, and the end point temperature is controlled to range from 1630 DEG C to 1660 DEG C; 5-7 kg / t steel lime and 1.0-2.0 kg / t steel calcium carbide are added into an LF furnace for deoxidation, a staged sulfur adding technology is adopted, the alkalinity of refining slag is controlled to be 2-4, reducing white slag is not produced for desulfurization, the temperature is increased to 1655-1685 DEG C in a submerged arc mode, VOD / VD is converted for vacuum treatment, a vacuum refining technology is adopted in VD, the vacuum degree is smaller than or equal to 67 Pa, the holding time is longer than or equal to 20 min, sulfur line feeding is not conducted after VD, and calcium treatment is not conducted; and when the soft blowing time is greater than or equal to 12 minutes, a continuous casting station is turned, the superheat degree of a continuous casting tundish is controlled to be 20-50 DEG C, and the constant pulling speed is 0.20 + / -0.2 m / The technology is suitable for producing the low-silicon low-aluminum high-sulfur steel through the electric furnace in a short process.

The invention discloses a refining method for improving the hit rate of boron-containing steel components, which comprises the following steps: LF (ladle furnace) rapid deoxidation and slagging, whole-course micro-positive-pressure nitrogen control, out-station slag condition adjustment, RH (Ruhrstahl Heraeus) station entering and carbonized rice husk adding, steel ladle bottom blowing argon gas opening in advance at the RH vacuum final stage, RH vacuum breaking argon gas flow setting, bulk ferroboron weighing and bagging. Setting calcium treatment speed and argon bottom blowing; adding carbonized rice husks to cover an argon port after calcium treatment; and sampling to confirm the boron content. The method has the advantages that the boron content hit rate of the boron-containing steel is increased and stabilized in the RH furnace refining process, the alloying effect is obviously improved, the boron component control difficulty and the recovery rate fluctuation are reduced, and the ferroboron yield is increased.

The application belongs to the technical field of wastewater treatment and recycling, and particularly relates to a desulfurization wastewater resource treatment method. The application can remove calcium ions to the maximum extent without reducing the concentration of magnesium ions in the first-stage calcium removal process by selecting a composite calcium removal agent with a specific composition, that is, effectively separating calcium ions and magnesium ions without introducing impurity ions, the concentration of calcium ions can be reduced to below 60 mg / L, and the removal rate of magnesium ions is below 10%; then the concentration of calcium ions is further reduced to below 10 mg / L through secondary calcium removal treatment; finally, through steps such as nanofiltration salt separation and concentration crystallization, sodium chloride with a purity of above 98% and magnesium sulfate heptahydrate with a purity of above 98.5% are obtained.

The invention discloses a thermal power plant circulating water calcium removal treatment method and system.The thermal power plant circulating water calcium removal treatment method comprises the steps that 1, reservoir water enters a crystallization granulation bed and reacts with seed crystal and alkali in the crystallization granulation bed to generate calcium carbonate particles; 2, the pH value in the crystallization granulation bed is controlled to be 10.1-10.6, so that the calcium hardness range of effluent of the crystallization granulation bed is 1.5 mmol / L to 1.0 mmol / L; step 3, discharging the calcium carbonate particles from the bottom of the crystallization granulation bed, carrying out solid-liquid separation, applying the discharged particles to a desulfurization system, and discharging water from the crystallization granulation bed to an efficient clarification tank; 4, coagulation and clarification treatment is conducted on effluent of the crystallization and granulation bed through an efficient clarification tank; 5, the efficient clarification tank is communicated with the circulating water tower forebay through a water outlet main pipe, a make-up water and sulfuric acid adding pipeline is arranged, and the make-up water and sulfuric acid adding pipeline is communicated with the water outlet main pipe. The thermal power plant circulating water calcium removal treatment method can reduce the hardness of the effluent and improve the concentration ratio of the circulating water.

The invention provides a method for preparing nickel-cobalt-manganese ternary regenerated liquid through multi-metal co-extraction and application, and the method comprises the following steps: firstly, carrying out calcium extraction treatment on a leaching solution obtained by removing iron, aluminum and copper from battery positive electrode black powder by adopting a first extraction organic phase to obtain a calcium-loaded organic phase and a calcium-removed raffinate; carrying out nickel-cobalt-manganese co-extraction on the calcium-removed raffinate by adopting a second extraction organic phase to obtain a nickel-cobalt-manganese-loaded organic phase, and carrying out reverse extraction treatment on the nickel-cobalt-manganese-loaded organic phase to obtain a nickel-cobalt-manganese mixed solution; and finally, the nickel-cobalt-manganese mixed solution is subjected to purification and impurity extraction treatment through a third extraction organic phase, and the nickel-cobalt-manganese ternary regenerated liquid is obtained. According to the preparation method provided by the invention, synchronous extraction of nickel, cobalt and manganese is realized, and the nickel-cobalt-manganese ternary regenerated liquid obtained by co-extraction can be directly used for in-situ preparation of the ternary positive electrode material, so that the regeneration period of the ternary positive electrode material is greatly shortened, the operation complexity and the production energy consumption are reduced, and the overall recovery cost is greatly reduced.

The invention discloses a method for preparing calcium sulfate and magnesium oxide and recovering nitric acid from a calcium and magnesium containing leaching solution of a chemical mineral separation byproduct. The method comprises the following steps: carrying out decalcification treatment on the calcium and magnesium containing leaching solution to obtain calcium sulfate and a decalcification solution containing dilute magnesium nitrate; evaporating the decalcified filtrate to obtain a solid-liquid mixture containing 72-76% of magnesium nitrate crystals; mixing dilute nitric acid with the solid-liquid mixture for reaction to obtain high-concentration nitric acid steam and a solid-liquid mixture of 52-56% magnesium nitrate crystals; separating the solid-liquid mixture to obtain magnesium nitrate crystals; dehydrating the magnesium nitrate crystal, and performing thermal decomposition to obtain magnesium oxide and a gas mixture; treating the nitric acid steam through a stripping section and a rectifying section of the concentration tower to obtain nitric acid steam with the concentration of 98% or above; nitric acid steam enters the bleaching tower to react to obtain finished nitric acid and concentrated nitric acid, and part of concentrated nitric acid flows back to the bleaching tower and the rectifying section of the concentration tower. According to the method, efficient utilization of chemical mineral separation byproducts is achieved, high-purity calcium sulfate and magnesium oxide products are prepared, and efficient recycling of nitric acid is achieved.

The invention provides a method for extracting organic matter components of shells. The method comprises the following steps: soaking the shells, ultrasonically removing seawater salt and silt on the surfaces, cleaning impurities on the surfaces by sodium hypochlorite, drying, crushing, sieving, decalcifying by a composite decalcifying solution to remove calcium carbonate on the surfaces of the shells, and retaining an organic matrix; and carrying out proteolysis on the decalcified solid organic matrix, carrying out heating ultrasonic extraction by using an extraction agent for 2-3 times, merging the supernatant, and concentrating and drying to obtain the shell active substance extract. The preparation method effectively retains organic matters, can obviously improve the extraction efficiency, is easy to obtain and low in cost, and the extraction agent is safe, environment-friendly, reusable and suitable for large-scale production.

The invention belongs to the technical field of ferrous metallurgy, and provides a novel method for producing aluminum-containing clean steel through slag washing calcium treatment, which comprises the following steps: promoting a pre-deoxidation reaction by using coke breeze added in the initial stage of converter tapping to realize top slag foaming, and then adding an aluminum block to forcibly remove oxygen in steel; after the molten steel enters an argon station, a proper amount of composite deoxidation slag former and aluminum skimmings are added to the slag surface to remove oxygen in the slag, the effect that argon station refining white slag is preposed is achieved within 4 min after the molten steel enters the station, and the refining effects that the total oxygen content in the molten steel is smaller than or equal to 30 ppm, and the desulfurization rate is larger than 50% are achieved; and finally, a proper amount of calcium is fed in an argon station in reference to the condition of total oxygen content in the steel, solid AL2O3 inclusions in the molten steel are accurately denatured into low-melting-point liquid inclusions such as 12CaO. 7AL2O3, CaO. AL2O3 and 3CaO. AL2O3, and the castability of the molten steel is improved.

The invention belongs to the technical field of metallurgy, and particularly relates to a cleanliness control method for medium-carbon aluminum-containing and sulfur-containing structural steel for an automobile transmission shaft. According to the medium-carbon aluminum-containing sulfur-containing structural steel, the technological process of converter-LF refining furnace-RH vacuum treatment furnace-continuous casting is adopted, the alkalinity of refining slag is controlled by determining the type of deoxidation materials in the converter tapping and LF process, the binary alkalinity of refining final slag is controlled to be 3.5-4.0, and the slag deoxidation and inclusion adsorption capacity is enhanced; in the LF process, through a calcium treatment process, aluminum oxide and other impurities difficult to float upwards are subjected to denaturation treatment, and the situation that a large number of calcium sulfide impurities more difficult to remove are generated due to improper calcium treatment is avoided; in the continuous casting process, nozzle nodulation is controlled through nozzle argon blowing, slow pulling speed and other operations. And finally, the castability of the molten steel is improved, meanwhile, non-metallic inclusions of rolled metal are effectively controlled, the flaw detection qualification rate is increased, and meanwhile the product crack occurrence rate of a user is effectively reduced.

The invention provides a method for extracting valuable metals from waste lithium-containing polishing powder. The method comprises the following steps: (1) carrying out acid leaching treatment on the waste lithium-containing polishing powder to obtain acid leaching residues and an acid leaching solution; (2) adjusting the pH value of the acid leaching solution to a first pH value, mixing the acid leaching solution with a first precipitator, and carrying out lanthanum precipitation treatment to obtain a lanthanum-precipitated solution and lanthanum-precipitated slag; (3) mixing the alum-forming reagent and the lanthanum-deposited liquid, heating and dissolving, and then carrying out aluminum removal treatment to obtain alum and a first aluminum-removed liquid; (4) mixing the first aluminum-removed liquid with a pH regulator, and carrying out impurity removal treatment to obtain an impurity-removed liquid; and (5) carrying out calcium removal treatment on the impurity-removed solution to obtain a lithium-rich solution. According to the method provided by the invention, valuable metals such as lithium, lanthanum and aluminum in the waste lithium-containing polishing powder are effectively recycled under the low-temperature condition, and the method is high in recycling and extracting rate, low in energy consumption and cost, simple in technological process, free of a complicated roasting treatment process and suitable for large-scale industrial production.

The present invention discloses a new process for preparing whiskers and recovering magnesium salts by using white mud, which includes: after separating white mud by sulfuric acid leaching, obtaining high-whiteness gypsum and magnesium sulfate solution containing calcium ions, then subjecting the magnesium sulfate solution containing calcium ions to decalcification treatment with carbonate to obtain high-purity magnesium sulfate solution; preparing high-purity magnesium sulfate monohydrate from the magnesium sulfate solution by a thermal crystallization method, preparing magnesium carbonate or magnesium bicarbonate by a carbonization process, and preparing high-purity magnesium oxide after calcination; preparing high-whiteness nanoscale calcium sulfate fibers and high-strength gypsum products from the high-whiteness gypsum by a hydrothermal method. The present invention not only turns waste into treasure, but also realizes the resource utilization, clean utilization and high-value utilization of white mud in the rare earth production industry.

The invention discloses an anti-flocculating-flow smelting method for a beam blank continuous casting machine, which comprises the following steps of: LF (ladle furnace) refining and calcium treatment process: when the temperature of molten steel reaches 1550-1580 DEG C at an LF station, feeding an iron-calcium core-spun yarn or a high-calcium yarn into the molten steel, and carrying out calcium treatment; during calcium treatment, the mass ratio of calcium to aluminum in molten steel is controlled to be 0.09-0.12; soft argon blowing treatment is carried out after calcium treatment, and the soft argon blowing time is not shorter than 10 minutes; a continuous casting protective pouring procedure: sealing from a steel ladle to a tundish by adopting a long nozzle matched with argon, wherein the argon flow at the sealing part is 5-15L / min; an alkaline covering agent is used in the tundish, and the alkalinity of the alkaline covering agent is controlled to be 1.8-2.5; and the superheat degree of the tundish molten steel is stably controlled to be 25-35 DEG C. Through systematic process design, the form and the number of inclusions in the molten steel are controlled, and stable high-quality molten steel is provided for a casting machine.

The invention relates to the technical field of metallurgy, in particular to a production process for reducing oxide inclusions of 20CrMnTiH gear steel. The process sequentially comprises the steps of electric furnace primary smelting, LF refining, RH vacuum treatment, continuous casting and rolling. The core of the method is that through whole-process systematic cooperative control, key process parameters such as an electric furnace end point, LF white slag refining, RH calcium treatment and continuous casting electromagnetic stirring and pulling speed are accurately regulated and controlled, and a set of complete inclusion prevention and treatment system is formed. According to the method, the total oxygen content in the steel can be stably controlled to be smaller than or equal to 15 ppm, and the grades of B-class and D-class inclusions are both smaller than or equal to 1.5, so that the fatigue life and the mechanical property consistency of the steel are remarkably prolonged, and the harsh requirement of high-end gear manufacturing for the material cleanliness is met.