Method for measuring water yield of hot-pressed iron block

Abstract

The invention provides a method for measuring the water outlet rate of a hot-pressed iron block. The method is used for solving the problem that in the prior art, a method for measuring the water outlet rate of a hot-pressed iron block is not high in accuracy. The invention provides a method for measuring the water yield of a hot-pressed iron block, which comprises the following steps: (1) carrying out slag-iron separation treatment on the hot-pressed iron block to obtain a separated iron block and separated slag particles; (2) carrying out first iron content determination treatment on the separated iron block by using a direct-reading spectrometer to obtain the iron content of the separated iron block; carrying out second iron content determination treatment on the separated slag particles through a potassium dichromate titration method to obtain the iron content of the separated slag particles; according to the mass of the hot-pressed iron blocks, the mass of the separated iron blocks, the iron content of the separated iron blocks and the iron content of the separated slag particles, the water outlet rate of the hot-pressed iron blocks is obtained; the determination method is high in result accuracy, and the operation process is simple and easy to control.

Description

Technical Field

[0001] The invention belongs to the technical field of detection and analysis, and particularly relates to a method for determining the water output rate of a hot-pressed iron block. Background Art

[0002] At present, the price of scrap steel is high, which has exceeded its original value. Therefore, some steel enterprises have begun to use hot-pressed iron blocks, which are produced by direct reduction technology of powder ore. The iron grade can reach 67.5-68% after ore dressing. Among them, the reducing gas is natural gas, which is processed into H2 and CO after reforming. The ore and the reducing gas flow in reverse, and after four-stage reduction, sponge iron is obtained, and then hot pressing is performed to obtain the final product - hot-pressed iron.

[0003] Hot-pressed iron has the characteristics common to ordinary sponge iron: high purity, low harmful impurity content, conducive to the production of high-quality steel, uniform quality, high strength, low powdering rate, more conducive to safe transportation and open-air storage, and high smelting steel yield, low gangue content, and low smelting energy consumption. Hot-pressed iron blocks are widely used and can usually be used in electric furnace production, as well as various smelting processes such as blast furnaces, converters, and electric furnaces. The advantages of its use are: 1. It alleviates the problem of shortage of scrap steel resources. 2. It shortens the smelting cycle and increases production. 3. The melting speed of hot-pressed iron blocks is fast, which is conducive to the early slag operation of the converter. 4. The chemical composition of hot-pressed iron blocks is stable, which is conducive to operation.

[0004] The water output rate of hot-briquette iron blocks is an important item for judging the quality of hot-briquette iron blocks, and it is also a very important criterion for company procurement. At the same time, the accurate measurement of hot-briquette iron blocks is also important for the cost calculation of converter iron output. However, there is currently no standard in the industry that can accurately analyze the water output rate of hot-briquette iron blocks.

[0005] Usually, the water yield of hot pressed iron blocks is determined by using electromagnetic induction to generate a strong alternating magnetic field to penetrate a graphite crucible to melt the iron-containing material, separate the slag from the iron, and determine the water yield by calculating the proportion of iron in the sample. However, the disadvantage of this method is that during the melting time control process of the sample, the graphite carbon in the sample and the impurity elements C, Mn, Si in the sample undergo a reduction reaction, which will enter the molten iron to increase the water yield, and a part of the iron will enter the slag during the iron-slag separation, affecting the measurement results.

[0006] In summary, there is an urgent need for a method that can accurately measure the water output rate of hot-pressed iron blocks. Summary of the invention

[0007] The invention provides a method for measuring the water output rate of a hot briquette iron block, which is used to solve the problem that the method for measuring the water output rate of a hot briquette iron block in the prior art has low accuracy.

[0008] The present invention provides a method for measuring the water output rate of hot briquette iron blocks, comprising the following steps:

[0009] (1) performing slag-iron separation treatment on the hot-pressed iron blocks to obtain separated iron blocks and separated slag particles;

[0010] (2) performing a first iron content determination process on the separated iron block using a direct reading spectrometer to obtain the iron content of the separated iron block; performing a second iron content determination process on the separated slag particles using a potassium dichromate titration method to obtain the iron content of the separated slag particles;

[0011] The water output rate of the hot briquette iron blocks is obtained according to the mass of the hot briquette iron blocks, the mass of the separated iron blocks, the iron content of the separated iron blocks and the iron content of the separated slag particles.

[0012] Compared with the prior art, the advantages of the present invention lie in that: the impurity elements of the hot-pressed iron blocks after slag-iron separation are removed by direct-reading spectrometer, and the iron content in the separated slag particles is analyzed by potassium dichromate redox titration method, and then the iron is combined and calculated to obtain the water output rate of the hot-pressed iron blocks. The analysis results of this method are highly accurate, and the operation process is simple and easy to control.

[0013] Further, according to the mass of the hot briquette iron block, the mass of the separated iron block, the iron content of the separated iron block and the iron content of the separated slag particles, the water yield rate of the hot briquette iron block is obtained, including obtaining the water yield rate of the hot briquette iron block by calculating according to formula (1);

[0014] W=m2 / m1×100%×Fe1+(m1-m2) / m1×100%×Fe2 Formula (1)

[0015] In the formula, W is the water output rate of the hot-pressed iron block, in %; m1 is the mass of the hot-pressed iron block, in g; m2 is the mass of the separated iron block, in g; Fe1 is the iron content of the separated iron block, in %; Fe2 is the iron content of the separated slag particles, in %.

[0016] Furthermore, before step (1), the method further comprises the following steps: placing the hot briquette iron block in an ultrasonic induction furnace for melting treatment, and then performing slag-iron separation treatment.

[0017] Furthermore, the melting treatment includes a first melting treatment for 5 to 6 minutes at an oscillating current of 95 to 100 A, and then a second melting treatment for 8 to 9 minutes at an oscillating current of 240 to 250 A, until the slag particles are completely separated from the molten iron, and the separated iron blocks and the separated slag particles are obtained after cooling.

[0018] Furthermore, before step (2), the separated iron block is subjected to a cutting process and a grinding process in sequence to obtain a cut surface of the separated iron block, and the cut surface of the separated iron block is subjected to a first iron content determination process.

[0019] Furthermore, before step (2), the particle size of the separated slag particles is not less than 160 mesh.

[0020] Furthermore, the second iron content determination process uses hydrochloric acid to dissolve the separated slag particles, and the temperature of the dissolution process is 300-400° C.; stannous chloride and titanium trichloride are used for reduction treatment, and the indicator is sodium diphenylamine sulfonate. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The present invention provides a method for measuring the water output rate of hot briquette iron blocks, comprising the following steps:

[0023] (1) performing slag-iron separation treatment on the hot-pressed iron blocks to obtain separated iron blocks and separated slag particles;

[0024] (2) performing a first iron content determination process on the separated iron block using a spectrometer to obtain the iron content of the separated iron block; performing a second iron content determination process on the separated slag particles using a potassium dichromate titration method to obtain the iron content of the separated slag particles;

[0025] The water output rate of the hot briquette iron blocks is obtained according to the mass of the hot briquette iron blocks, the mass of the separated iron blocks, the iron content of the separated iron blocks and the iron content of the separated slag particles.

[0026] In the implementation, weigh about 700g-800g of hot pressed iron block sample (using No. 8 crucible) and record it as m1, put it into the graphite crucible, and use special tools to put the graphite crucible into the induction furnace; adjust the oscillating current to about 100A, about 5min, continue to adjust the oscillating current to full load 240-250A and run for about 8 minutes, wait for the slag in the sample to float up and completely separate from the molten iron, and rotate the power adjustment knob to zero; stabilize for about 10s, take it out with a special tool, put it in a fixed position, wait for it to cool naturally, and after the graphite crucible turns black, move it to a designated location outdoors and smash the graphite crucible with a hammer. Take out the iron block with a clamp, put it in a sink filled with cold water, cool it quickly, take it out after 30s, put it on the refractory brick to cool naturally to room temperature, remove the surface slag, and weigh the mass of the separated iron block with a balance, record it as m2.

[0027] The separated iron block is cut into a flat surface, then ground with a sanding machine, and then the ARL3460 direct reading spectrometer is used to measure the first iron content of the cross section of the separated iron block. Different cross sections are selected for parallel measurement 2 to 3 times, and the average value is taken and the result is recorded as Fe1.

[0028] The separated slag particle samples are ground and sieved to make the sample size not less than 160 meshes, then (0.2000±0.0001) g of the sample is weighed and dissolved in hydrochloric acid at a temperature of 300-400°C; reduced with stannous chloride and titanium trichloride, sodium diphenylamine sulfonate indicator is added dropwise, and titrated with potassium dichromate standard solution to perform a second iron content determination, and the result is recorded as Fe2; wherein, the potassium dichromate titration method is carried out with reference to GB / T 6730.65-2009.

[0029] The water output rate of hot briquette is calculated according to formula (1):

[0030] W=m2 / m1×100%×Fe1+(m1-m2) / m1×100%×Fe2 Formula (1)

[0031] In the formula, W is the water output rate of the hot-pressed iron block, in %; m1 is the mass of the hot-pressed iron block, in g; m2 is the mass of the separated iron block, in g; Fe1 is the iron content of the separated iron block, in %; Fe2 is the iron content of the separated slag particles, in %.

[0032] Hereinafter, a method for determining the water yield of hot briquette iron blocks provided by the present invention will be described in detail through specific examples.

[0033] Example 1

[0034] (1) Sample melting and slag-iron separation: Weigh 800±0.01g of hot-pressed iron block sample (using No. 8 crucible) and record it as m1, put it into a graphite crucible, and use special tools to put the graphite crucible into the induction furnace; adjust the oscillating current to about 100A, run for about 5 minutes, and continue to adjust the oscillating current to full load 250A for about 8 minutes. After the slag in the sample floats up and is completely separated from the molten iron, turn the power adjustment knob to zero; stabilize for about 10 seconds, take it out with a special tool, put it in a fixed position, wait for it to cool naturally, and after the graphite crucible turns black, move it to a designated location outdoors and smash the graphite crucible with a hammer. Take out the iron block with a clamp, put it in a sink filled with cold water, and cool it quickly. After 30 seconds, take it out and place it on refractory bricks to cool naturally to room temperature, remove the surface slag, and weigh the iron block with a balance. The weight is 752.05g, recorded as m2;

[0035] W (including impurity elements) = m2 / m1×100%=752.05 / 800×100%=94.01%;

[0036] (2) Removal of impurities in iron: The separated iron block was cut into a flat surface, then ground with a sanding machine, and the iron content was measured with an ARL3460 direct reading spectrometer. The sample was measured 2 to 3 times in parallel, and the average value was taken and recorded as Fe1. The measured Fe1 was 96.69%;

[0037] W (excluding iron in slag) = m2 / m1×100%×Fe1=90.90%;

[0038] (3) Determination of iron content in slag: The separated slag particles were ground and sieved to a sample size of ≥160 mesh, and then (0.1999) g of the sample was weighed and dissolved in hydrochloric acid at a temperature of 400°C. The sample was reduced with 60 g / L stannous chloride and 5% titanium trichloride by mass, and 2 g / L sodium diphenylamine sulfonate was used as an indicator. The sample was titrated with 0.0033 mol / L potassium dichromate standard solution, and the standard solution consumption was 20.66 ml. The blank and standard sample were measured at the same time. The second iron content was measured using the content of the standard sample and the number of titrations. The sample was measured 2 to 3 times in parallel, and the average value was taken. The result was recorded as Fe2, and the measured Fe2 was 11.54%;

[0039] The water output rate of hot briquette is calculated according to formula (1):

[0040] W=m2 / m1×100%×Fe1+(m1-m2) / m1×100%×Fe2

[0041] =752.05 / 800×100%×96.69%+47.95 / 800×100%×11.54%

[0042] =91.59%.

[0043] Embodiments 2 to 15

[0044] The same hot briquette iron block samples from different batches as those in Example 1 were used, and the measuring method was the same as that in Example 1.

[0045] Test Example 1

[0046] The different samples in the above embodiments are respectively subjected to X-ray spectroscopy analysis, including the following steps:

[0047] Different batches of hot-pressed iron block samples were drilled with a bench drill. The surface oxide layer was removed before drilling. The upper and lower surfaces and sides of the samples were drilled respectively. After that, the samples were ground to reach the particle size required by the instrument. 4±0.0002g of mixed solvent (the mass ratio of sodium carbonate: boric acid: potassium carbonate is 3:2:1) was weighed in a quantitative filter paper, and 0.2±0.0002g of hot-pressed iron block sample was added and mixed. The sample was wrapped into a ball with filter paper. The above spherical sample was placed in a pre-oxidized graphite crucible and baked in a muffle furnace heated to 950°C for 15 minutes. After taking it out, the crucible was placed in an isolation box to cool the graphite. The hot-pressed iron block oxide ball was taken out of the graphite crucible with tweezers and cleaned.

[0048] Then, perform secondary melting in a platinum dish: weigh 6g of flux (mass ratio of lithium tetraborate: lithium metaborate is 67:33) in a platinum dish, add about 1g of ammonium iodide and mix well, add hot pressed iron block sample ball, put the platinum dish into a melting machine and melt at 1050℃ for 900s. Take it out and let it stand to cool, and get the melted sample, then use X-ray fluorescence spectrometer to select the corresponding standard curve to determine the iron content.

[0049] The test results of different samples in the above embodiments obtained by the determination method provided by the present invention and the test results obtained by the X-ray spectroscopy analysis method in the test example are shown in Table 1.

[0050] Table 1

[0051]

[0052]

[0053] Comparing the results in Table 1, it can be seen that the method for determining the water yield of a hot-pressed iron block provided by the present invention uses a direct-reading spectrometer to remove impurities, and after the potassium dichromate method is used to determine the iron element in the slag, the final water yield result is calculated to have an average error of 0.61% with the X-ray spectrometer analysis result, which meets the requirements of relevant standards. The determination method provided by the present invention has high accuracy, a simple determination method, high work efficiency, and reduces the steps of drilling samples with a bench drill, increases the safety of the operation process, and has strong controllability in the determination process. The determination results can be used for trade settlement and can ensure the accuracy of converter batching during steelmaking.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. If these modifications and variations fall within the scope of the claims of the present invention and their equivalent technologies, they should be considered to be within the protection scope of the present invention.

Claims

1. A method for measuring the water yield of hot briquette iron, characterized in that: The following steps are involved: (1) performing slag-iron separation treatment on the hot-pressed iron blocks to obtain separated iron blocks and separated slag particles; (2) performing a first iron content determination process on the separated iron block using a direct reading spectrometer to obtain the iron content of the separated iron block; performing a second iron content determination process on the separated slag particles using a potassium dichromate titration method to obtain the iron content of the separated slag particles; The water output rate of the hot briquette iron blocks is obtained according to the mass of the hot briquette iron blocks, the mass of the separated iron blocks, the iron content of the separated iron blocks and the iron content of the separated slag particles.

2. The method for measuring the water yield of hot briquette iron according to claim 1, characterized in that: The method of obtaining the water yield rate of the hot briquette iron block according to the mass of the hot briquette iron block, the mass of the separated iron block, the iron content of the separated iron block and the iron content of the separated slag particles comprises obtaining the water yield rate of the hot briquette iron block by calculating according to formula (1); W = m2 / m1×100%×Fe1+(m1-m2) / m1×100%×Fe2 Formula (1) In the formula, W is the water output rate of the hot-pressed iron block, unit is %; m1 is the mass of the hot-pressed iron block, unit is g; m2 is the mass of the separated iron block, unit is g; Fe1 is the iron content of the separated iron block, unit is %; Fe2 is the iron content of the separated slag particles, unit is %.

3. The method for measuring the water yield of hot briquette iron according to claim 1, characterized in that: Before step (1), the method further comprises the following steps: placing the hot briquette iron block in an ultrasonic induction furnace for melting treatment, and then performing slag-iron separation treatment.

4. The method for measuring the water yield of hot briquette iron according to claim 3, characterized in that: The melting treatment includes a first melting treatment for 5 to 6 minutes at an oscillating current of 95 to 100 A, and then a second melting treatment for 8 to 9 minutes at an oscillating current of 240 to 250 A, until the slag particles are completely separated from the molten iron, and the separated iron blocks and the separated slag particles are obtained after cooling.

5. The method for measuring the water yield of hot briquette iron according to claim 1, characterized in that: Before step (2), the separated iron block is subjected to a cutting process and a grinding process in sequence to obtain a cut surface of the separated iron block, and the cut surface of the separated iron block is subjected to a first iron content determination process.

6. The method for measuring the water yield of hot briquette iron according to claim 1, characterized in that: Before step (2), the particle size of the separated slag particles is not less than 160 mesh.

7. The method for measuring the water yield of hot briquette iron according to claim 1, characterized in that: The second iron content determination process uses hydrochloric acid to dissolve the separated slag particles, and the temperature of the dissolution process is 300-400° C.; stannous chloride and titanium trichloride are used for reduction treatment, and the indicator is sodium diphenylamine sulfonate.

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