CN-122016994-A - Quantitative characterization method for rare earth content in blast furnace pig iron

CN122016994ACN 122016994 ACN122016994 ACN 122016994ACN-122016994-A

Abstract

The invention relates to the technical field of material analysis, and discloses a quantitative characterization method of rare earth content in blast furnace pig iron, which comprises the steps of crushing a blast furnace pig iron sample into particles, heating and digesting the particles in concentrated hydrochloric acid, filtering a solution after the digestion is completed, collecting filtrate, fixing the volume to be measured, and mixing filter residues with KOH and KOH to be measured Mixing in a crucible, putting into a muffle furnace for melting, then alternately flushing the melt in the crucible by adopting an HCl aqueous solution and deionized water, adding concentrated hydrochloric acid to clear the collected suspension, and cooling to a constant volume for measurement. And measuring the concentration of the rare earth element in the solution to be measured by using an inductively coupled plasma mass spectrometer (ICP-MS), and carrying the concentration into a formula to calculate so as to obtain the rare earth content in the blast furnace pig iron. The invention can comprehensively analyze the content of rare earth elements in each phase of the blast furnace pig iron in laboratory research and production practice, accurately completes the determination work of the content of rare earth elements in the blast furnace pig iron, and has the characteristics of safe experimental process, high efficiency of pretreatment process, low price of used medicines and the like.

Inventors

QU WEI
REN HUIPING
WU ZHONGWANG
DONG FANG

Assignees

内蒙古科技大学

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (8)

1. A quantitative characterization method of rare earth content in blast furnace pig iron is characterized by comprising the following steps: (1) Crushing a blast furnace pig iron sample into particles; (2) Placing the granular pig iron sample into an conical flask or beaker filled with concentrated hydrochloric acid, digesting at 50-95 ℃, and filtering the solution after digestion is completed; (3) Collecting the filtered solution into a beaker, naturally cooling to room temperature, transferring the solution into a volumetric flask for constant volume and measuring; (4) Transferring the filter residues collected after filtration into a crucible with a cover, adding KOH and K2CO3, uniformly mixing, and then placing the crucible with the cover in a muffle furnace for heating and melting; (5) Taking out the heated and insulated crucible, alternately flushing the crucible cover and the crucible by adopting 1% -10% of HCl aqueous solution and deionized water until the crucible cover and the crucible are completely flushed, and collecting the flushed suspension into a beaker; (6) Stirring the suspension, heating to 70-95 ℃, adding concentrated hydrochloric acid, stirring until the suspension becomes clear aqueous solution, stopping heating, naturally cooling to room temperature, transferring the solution into a volumetric flask for constant volume, and measuring; (7) And measuring the concentration of the rare earth element in the solution to be measured after the constant volume by using an inductively coupled plasma mass spectrometer (ICP-MS), and converting the solid solution quantity of the rare earth element in the tapping iron material.
2. The quantitative characterization method of rare earth content in blast furnace pig iron according to claim 1, wherein the particle size of the granular pig iron in the step (1) is 1 mm to 10 mm.
3. The quantitative characterization method of the rare earth content in the blast furnace pig iron according to claim 1, wherein the digestion process in the temperature range of 50 ℃ to 95 ℃ in the step (2) can be performed on a water bath pot, an electric heating plate or a resistance wire furnace, and meanwhile deionized water is required to be intermittently added into a conical flask or a beaker to prevent the liquid in the container from being evaporated.
4. The quantitative characterization method of the rare earth content in the blast furnace pig iron according to claim 1, wherein the filtering process in the step (2) adopts an organic filter membrane with the pore diameter of 0.2-0.4 μm to carry out vacuumizing acceleration filtration in a sand core filter or 3-6 layers of slow quantitative filter paper in a buchner funnel, and after the first filtration, 10-15 mL of deionized water is added to continue to wash the filter residue for 3-5 times and filtering.
5. The quantitative characterization method of the rare earth content in the blast furnace pig iron according to claim 1, wherein the filtered solution in the step (3) is collected into a beaker and subjected to a constant volume process, after the solution is transferred for the first time, a suction filtration bottle is washed 3-5 times with 10-15 mL of deionized water, then when the solution is transferred from the beaker to a volumetric flask, after the solution is transferred for the first time, the beaker is washed 3-5 times with 5-10 mL of deionized water, and finally, the concave liquid surface of the solution is filled up to the scale mark of the volumetric flask with deionized water.
6. The quantitative characterization method of the rare earth content in the blast furnace pig iron according to claim 1, wherein the filter residue in the step (4) is transferred to a crucible together with a filter membrane or quantitative filter paper, the crucible can be made of nickel, silver or platinum, the mass ratio of the addition amount of KOH and K 2 CO 3 to the sampling of the blast furnace pig iron is (1.5-3): 1.5): 1, the melting temperature of the muffle furnace is 600-900 ℃, and the heat preservation time is 25-60 min.
7. The quantitative characterization method of the rare earth content in the blast furnace pig iron according to claim 1, wherein the constant volume process in the step (6) is characterized in that after the solution is transferred for the first time, 10 mL to 15 mL of deionized water is used for rinsing the beaker for 3 to 5 times, and finally, the concave liquid surface of the solution is filled up to the scale mark of the volumetric flask by using the deionized water.
8. The quantitative characterization method of rare earth content in blast furnace pig iron according to claim 1, wherein the quantitative process in step (7) is characterized in that after the concentration is measured by using an inductively coupled plasma mass spectrometer, the quantitative process can be represented by the following formula Measuring; W is the content of rare earth elements in the blast furnace pig iron, C 1 is the concentration of the rare earth elements in the solution after the filtrate is subjected to constant volume, V 1 is the volume of the filtrate after the filtrate is subjected to constant volume, C 2 is the concentration of the rare earth elements in the solution after the filter residue is prepared into the solution after the solution is subjected to constant volume, V 2 is the volume of the solution after the filter residue is prepared into the solution after the solution is subjected to constant volume, and M is the mass of the sample after electrolysis.

Description

Quantitative characterization method for rare earth content in blast furnace pig iron Technical Field The invention belongs to the technical field of material analysis, and particularly relates to a quantitative characterization method of rare earth content in blast furnace pig iron. Background The bayan obo ore is taken as the largest iron-rare earth-niobium resource co-associated deposit in the world, a large amount of valuable element resources are contained in the mineral deposit, and along with the continuous development of science and technology, the research and exploration aiming at the bayan obo ore become hot spots in the scientific community. The bayan obo ore is used as one of main iron ore sources of Baotou iron and steel groups, and the rare earth elements in the bayan obo ore are found to have trace residues in steel products along with the ferrous metallurgy process in the last 90 th century. Up to the recent years, the inheritance behavior study of the co-associated rare earth elements in the baiyunebo ore in the ferrous metallurgy process discovers that trace rare earth elements still exist in the blast furnace molten iron and enter the converter steelmaking process in the blast furnace ironmaking process. The above findings are different from the conventional thermodynamic explanation that rare earth oxides in iron concentrates cannot be reduced to molten iron and completely enter blast furnace slag in a blast furnace ironmaking process, and thus, the blast furnace ironmaking process is one of key technological processes of whether rare earth elements co-associated with bayan obo ores can be transferred to steel. Therefore, how to accurately perform quantitative analysis on the rare earth content in the blast furnace molten iron is a key characterization technology for proving whether the co-associated rare earth elements in the iron concentrate can exist in the molten iron after the iron concentrate is ironed by the blast furnace. The current method for measuring the rare earth content in the steel material mainly comprises the steps of issuing GB/T223.49-1994 extraction separation-azochlorophosphine mA spectrophotometry for measuring the total rare earth content by a steel and alloy chemical analysis method by the national technical administration in 1994, adopting hydrochloric acid and nitric acid to digest the total rare earth content in the standard, adopting an extractant to classify rare earth ions and iron ions, and adopting a color-developing agent to measure the rare earth content in the steel material in a spectrophotometer, wherein the measuring range is 0.0010% -0.20%. The national market supervision and management bureau of 2022, the national standardization management committee issued GB/T26416.1-2022 part 1 of rare earth iron alloy chemical analysis method, namely the determination of the total rare earth, the method adopts oxalic acid gravimetric method, EDTA titration method and inductively coupled plasma emission spectrometry, and the method is suitable for measuring the rare earth content in the rare earth iron alloy, and the measurement range is 1.00% -20.00%. Wang Yapeng of Benxi iron and steel discloses a method for detecting cerium element content in rare earth steel, which adopts an electrolytic method and a chemical separation method to respectively detect the content of rare earth cerium in oxides, sulfides and oxysulfide in the steel, and finally adds up to obtain the content of rare earth cerium in the steel. The method for measuring the rare earth content in the steel by adopting nitric acid, hydrochloric acid and perchloric acid to digest the steel sample and spectrophotometry is also only suitable for measuring the total rare earth content in the steel. The methods of rapid determination of total rare earth in spheroidal graphite cast iron, azo chlorophosphine III direct photometry, determination of total trace rare earth in spheroidal graphite cast iron, tribromoazo swelling direct photometry, rapid analysis of total rare earth in spheroidal graphite cast iron and low alloy steel, oxalic acid masking, azo chlorophosphine III direct photometry, rapid determination of total rare earth in spheroidal graphite cast iron, extraction colorimetry and the like all adopt an acid dissolution method to digest a cast iron sample, then determine the concentration of rare earth ions in the solution, and finally convert the concentration into the content of rare earth in cast iron. It is clear that the existing method for measuring the rare earth content in the steel material can only measure the rare earth content in the steel material or the rare earth content in the graphite phase in the cast iron material. However, blast furnace pig iron is similar to cast iron, and because of the higher carbon content, the blast furnace pig iron contains more graphite phases, and the rare earth content in the graphite phases is often ignored according to the existing rare earth conte