Method for measuring amount of seamless solid calcium wire and elemental calcium

Abstract

The present invention discloses a method for determining the amount of calcium wire and elemental calcium in a seamless solid calcium wire. The method is as follows: first, prepare a grinding fixture, a grinding powder collection box, and a hydrogen measurement device; then, use a cutting machine to intercept 2 representative sample blocks; use a grinding wheel to cut along the axial direction of the calcium wire sample to cut open the iron skin layer, use the grinding powder collection fixture and the collection box to collect the cutting powder, wash the elemental calcium on the iron skin layer and the grinding powder with a sodium chloride solution, and weigh the mass of the iron skin layer to calculate the amount of solid calcium wire. Quickly drill calcium chip samples from the calcium core, use the hydrogen measurement device to determine the content of total metals in the calcium core, use the ICP-OES method to determine the contents of elemental magnesium and aluminum, and calculate the amount of elemental calcium. The present invention has the characteristics of fast peeling speed of the iron skin layer, being able to obtain blocky calcium core samples, low loss of iron during peeling of the iron skin layer, eliminating the influence of magnesium and aluminum on the measurement result of elemental calcium, and being able to distinguish elemental calcium from combined calcium.

Description

Technical Field

[0001] The present invention relates to the technical field of the determination of the amount of calcium wire and elemental calcium, and specifically to a method for determining the amount of calcium wire and elemental calcium in seamless solid calcium wire. Background Art

[0002] At present, seamless solid calcium wire is widely used as a steelmaking deoxidizer in the metallurgical industry. The seamless solid calcium wire is composed of a coating layer and a core calcium wire coated inside the coating layer. The coating layer of the solid pure calcium cored wire is made of steel material, and the core is made into a special structure of a pure calcium solid core. Different enterprises have different regulations on the meter weight of the calcium core wire, the meter weight of the calcium wire, and the content of elemental calcium in the calcium core, but the differences are not significant. For example, the technical conditions of seamless solid calcium wire Q / ZZWL002-2017 stipulate that the diameter of the calcium core wire is 7±0.2mm, the meter weight (g / m) of the calcium core wire is >52, the meter weight (g / m) of the calcium wire with a 1.0mm thick steel strip coating layer is <220, the calcium core wire is Ca>97%, Mg<0.8%, Al<1.0%. When accepting according to this regulation, it is necessary to measure the meter weight of the calcium core wire, the meter weight of the calcium wire, and the content of elemental calcium in the calcium core.

[0003] Literature 1 (Analysis method of elemental calcium in cored wire, Chinese Patent Application Publication No. CN102539279A) and Literature 2 (Method for determining the content of metallic calcium in calcium-based cored wire, Chinese Patent Application Publication No. CN103822850A) both use the gas volumetric method to determine the amount of elemental calcium. Its technical feature is that it can well analyze elemental calcium and combined calcium. The difference between the above two methods is that the former uses water to dissolve calcium, and the latter uses ammonium chloride solution. The defect is that the influence of elemental aluminum and elemental magnesium cannot be eliminated. Literature 3 (Detection method of calcium content in seamless calcium wire, Chinese Patent Application Publication No. CN108663476A) and Literature 4 (Detection method of calcium content in solid calcium wire, Chinese Patent Application Publication No. CN112858570A) use the method of measuring total calcium as elemental calcium. Literature 5 (Sampling preparation and determination method of high calcium wire, Chinese Patent Application Publication No. CN103234771A) uses the impurity subtraction method to determine the calcium content. The methods described in Literature 3, 4, and 5 belong to wet chemical analysis methods. Its technical feature is that the accuracy of total calcium determination is relatively high. Its defect is that it cannot distinguish between elemental calcium and combined calcium.

[0004] Document 5 also discloses a method for cutting with a hacksaw, using diagonal pliers and a flat-bladed screwdriver to remove the iron sheet, remove (pour out) the core powder, and weigh it, calculating the ratio of iron sheet to core powder. This method is characterized by being able to effectively remove the iron sheet and weigh the core (powder). However, the sawdust generated during the sawing of the iron sheet is difficult to completely remove from the core powder using a magnet, and the loss and oxidation of the core powder during the sawing process are also difficult to avoid. Document 3 first uses a sodium chloride solution to dissolve elemental calcium, which can effectively separate calcium and iron. However, since a solid block sample of the calcium core cannot be obtained, the elemental calcium determination cannot be completed. Furthermore, hydrochloric acid is used to neutralize the calcium hydroxide solution to prevent calcium hydroxide from adhering to the iron sheet and causing calcium loss. However, during the neutralization process, the hydrochloric acid reacts with the iron, causing iron loss, resulting in a low result for the iron sheet layer. Document 6 (Chinese patent application publication number CN109030275A, a method for measuring the calcium content of seamless pure calcium wire) uses a method of separating the iron sheet and the calcium core by soaking them in 1525g / L sodium chloride solution twice. This method can also separate calcium and iron, but similarly no solid calcium core sample can be obtained, and the content of elemental calcium cannot be directly measured. Moreover, since the iron sheet is soaked in sodium chloride solution for 4 days, iron rust loss is also inevitable.

[0005] In summary, the problems of the existing technology are:

[0006] 1. The stripping speed of the iron layer is slow, and no solid calcium core sample can be obtained after stripping;

[0007] 2. There will be loss of iron when peeling off the iron layer;

[0008] 3. The measurement results of elemental calcium are affected by elemental aluminum and magnesium;

[0009] 4. The test results cannot distinguish between elemental calcium and combined calcium. Summary of the Invention

[0010] In order to solve the deficiencies mentioned in the above-mentioned background technology, the purpose of the present invention is to provide a method for determining the amount of calcium and elemental calcium, which has a fast iron sheet stripping speed, can obtain a block calcium core sample, has extremely low iron loss when stripping the iron sheet, eliminates the influence of magnesium and aluminum on the elemental calcium measurement results, and can distinguish between elemental calcium and combined calcium.

[0011] The purpose of the present invention can be achieved through the following technical solutions:

[0012] A method for determining the amount of calcium wire and elemental calcium in a seamless solid calcium wire, the method comprising the following steps:

[0013] Step 1: Prepare the grinding fixture and grinding powder collection box.

[0014] Step 2: Prepare a hydrogen measuring device.

[0015] Step 3: Use a cutting machine to remove the two ends of the seamless solid calcium wire sample, and then divide it into two equal sections. From one of the sections, cut a 15 - 20 mm sample block at each end, obtaining a total of 2 sample blocks. Weigh the mass of the 2 sample blocks together and record it as ms.

[0016] Step 4: Place the 2 sample blocks in the arc-shaped clamping groove of the grinding fixture, making the end face of the sample block coincide with the end face of the grinding fixture. Place the front flat plate of the grinding powder collection box under the grinding fixture, clamp the grinding fixture with a bench vice. Seal a magnet with a self-sealing plastic bag and place it at the connection between the grinding fixture and the grinding powder collection box, so that the magnet attracts both the grinding fixture and the grinding powder collection box simultaneously. Use a hand-held abrasive wheel cutting machine to axially cut the iron skin layer of the sample block. When one side of the iron skin layer is cut through, rotate the sample block 180° along the circumference of the sample, continue to clamp the 2 sample blocks with the bench vice and cut the iron skin layer until it is completely cut through. Take out the sample block from the fixture and separate the calcium core from the iron skin layer.

[0017] Step 5: Quickly drill calcium chips from the two calcium cores with a drill press. Collect 0.1 - 0.2 g of calcium chips below 0.5 mm from the surface of each core, mix them, and then quickly weigh 0.15 - 0.20 g accurate to 0.0001 g and record it as msCa (g). Place it in a sample tube. Place the sample tube together with the calcium chip sample on the sample tube connecting rod on the rubber stopper of the conical flask. Add 10 - 20 mL of phosphoric acid with a concentration of 50 g / L to the reaction flask, install the reaction flask stopper and connect the gas measuring device. Keep the three-way piston in the three-way state of the atmosphere, the conical flask and the gas measuring tube. Keep the water level of the leveling flask, the level of the gas measuring tube and the 0 scale line of the gas measuring tube in the same plane. Turn the three-way piston to connect the gas measuring tube and the conical flask and cut off the atmosphere. Move the leveling flask to a lower position, tilt the reaction flask to pour out the sample in the sample tube to ensure that the aluminum chip sample is completely poured out. Shake the conical flask to make the phosphoric acid in the conical flask enter the sample tube to ensure that all the loaded aluminum chips react fully with the phosphoric acid. After the reaction is complete, cool the conical flask to room temperature with running water at room temperature and read the volume reading on the gas measuring tube and record it as Vs (mL).

[0018] Weigh 0.10 g of high-purity aluminum chips accurately to 0.0001 g, denoted as msAl (g), and place them in the sample tube. Put the sample tube together with the sample on the sample tube connecting rod on the rubber stopper of the conical flask. Add 20 - 30 mL of phosphoric acid with a concentration of 50 g / L to the conical flask, install the conical flask stopper and connect the gas measuring device. Keep the three-way piston in the three-way state of the atmosphere, the conical flask and the gas measuring tube. Keep the water level of the leveling flask, the level of the gas measuring tube and the 0 scale line of the gas measuring tube in the same plane. Turn the three-way piston to connect the gas measuring tube and the conical flask, and cut off the atmosphere. Move the leveling flask to a lower position, tilt the conical flask to pour out the sample in the sample tube, ensure that all the aluminum chip samples are poured out, shake the conical flask to make the phosphoric acid in the conical flask enter the sample tube, ensure that all the loaded aluminum chips react fully with the phosphoric acid. After the reaction is complete, cool the conical flask to room temperature with running water at room temperature, read the volume reading on the gas measuring tube, denoted as VAl (mL). The calculation of the total amount WCaT% of calcium, magnesium and aluminum in elemental calcium is carried out according to formula (Ⅰ).

[0019]

[0020] Step 6. Separation of grinding powder

[0021] Transfer the grinding fixture, the grinding powder collection box and the magnet together to a clean A4 copy paper. Remove the magnet on the grinding fixture and the grinding powder collection box. Carefully collect all the grinding powder on the grinding powder collection box and the grinding fixture onto the clean copy paper. Use the originally sealed magnet to pick up the grinding powder placed on the clean copy paper, and discard the grinding powder on the copy paper that cannot be picked up by the magnet. Open the self-sealing plastic bag, take out the magnet, and transfer all the iron powder outside the plastic bag onto the copy paper. Repeat the magnetic separation operation as described above once to obtain the grinding iron powder

[0022] Step 7. Place the grinding iron powder and 4 iron sheet blocks in a 100 mL glass beaker, add 10 mL of ammonium chloride solution with a concentration of 100 g / L, soak for 5 min. Place a magnet at the bottom of the beaker, pour out the ammonium chloride completely by decantation, then wash the iron powder and iron sheets 3 times with pure water, and dry them with hot air. Weigh the mass of the iron powder and iron sheets, denoted as mFe. The calculation of the calcium wire amount is carried out according to formula (Ⅱ).

[0023]

[0024] Step 8. Determination of aluminum and magnesium

[0025] 1. Preparation of the sample solution

[0026] After completing the measurement of the hydrogen gas volume, transfer the solution in the conical flask to a 100 mL volumetric flask. Wash the conical flask (4) with 2 - 3 mL of pure water, transfer the washing solution into the volumetric flask, wash 3 - 4 times, and dilute to the scale with pure water, then shake well.

[0027] 2. Preparation of calibration curve solution

[0028] Take 7 100-mL volumetric flasks. Add 18 mL of CaCl2 solution (10 mg Ca / mL) and 10 mL of phosphoric acid with a concentration of 50 g / L to each volumetric flask. Then, add 0.0, 0.2, 0.5, 1.0, 2.0, 3.0, and 5.0 mL of aluminum standard solution (1.0 mg Al / mL) and magnesium standard solution (1.0 mg Mg / mL) respectively, and dilute to the mark with pure water. Shake well.

[0029] 3. Measurement

[0030] On an inductively coupled plasma atomic emission spectrometer (ICP-OES), measure under the optimized working conditions. First, measure the calibration curve standard solution. Using the amounts of magnesium and aluminum as the abscissa and the corresponding characteristic spectral intensities of magnesium and aluminum as the ordinate, establish calibration curves of spectral intensity versus the amounts of magnesium and aluminum respectively. Then, measure the spectral intensity of the sample solution and read out the amounts of magnesium and aluminum on the inductively coupled plasma atomic emission spectrometer, denoted as mMg and mAl (mg). Calculate the mass fractions of magnesium and aluminum according to formulas (Ⅲ) and (Ⅳ).

[0031]

[0032]

[0033] Step Nine: Calculation of elemental calcium

[0034] Elemental calcium is calculated according to formula (Ⅴ).

[0035]

[0036] As a preferred embodiment of the present invention, the preparation method of the grinding fixture and the grinding powder collection box is as follows: Take a steel plate with a thickness of 1 mm and side lengths of 30 mm and 70 mm respectively. Bend it at the midpoint of the length direction into a semi-circular arc plate with a diameter of 12 mm. Then, symmetrically bend the two sides of the semi-circular arc plate outward by 90 degrees so that the chord formed by the two bending points is parallel to the diameter line of the semi-circular arc, and the vertical line length from the chord line to the vertex of the semi-circular arc is greater than the radius of the semi-circular arc (6 mm) to obtain the grinding fixture. Take another steel plate with a thickness of 1 mm, a length of 110 mm, and a width of 70 mm. Cut off 20×20 squares at the two corners at one end, cut off a 15×10 rectangle at the center of the other end, and cut off 20×10 rectangles at the two corners. Bend the 100-mm long sides on both sides by 90 degrees and bend the 30-mm short side at the top by 90 degrees to obtain the grinding powder collection box.

[0037] As a preferred embodiment of the present invention, the hydrogen measuring device includes a reactor, a constant temperature water bath, a connecting pipe, a gas measuring tube and a leveling bottle. The reactor includes a rubber stopper, a sample loading tube connecting rod, a sample loading tube, a conical flask and a three-way piston. The rubber stopper is located inside the mouth of the conical flask. The sample loading tube connecting rod is arranged at the bottom of the rubber stopper. The sample loading tube is arranged on the sample loading tube connecting rod. The sample loading tube is a glass tube with one end open, having an inner diameter of 15 mm and a depth of 10 mm. The axis of the sample loading tube is parallel to the bottom surface of the rubber stopper. The constant temperature water bath is provided with a circulating water inlet and an outlet, and the constant temperature water bath is filled with constant temperature circulating water. A first silica gel connecting tube is arranged between the rubber stopper and the gas measuring tube, and the first silica gel connecting tube penetrates through the rubber stopper. A three-way piston is arranged on the first silica gel connecting tube. A second silica gel connecting tube is arranged between the gas measuring tube and the leveling bottle. The volume of the constant temperature water bath is large enough to accommodate the conical flask. The gas measuring tube is a 150 mL graduated gas measuring tube with a minimum scale of 0.2 mL, and the volume of the leveling bottle is 1000 mL.

[0038] As a preferred embodiment of the present invention, the grinding powder is the powder and chips generated by the interaction of the equipment and the sample during the grinding and cutting process.

[0039] As a preferred embodiment of the present invention, the steel plate is made of ordinary carbon steel or low alloy steel.

[0040] As a preferred embodiment of the present invention, the magnet is a bar-shaped or circular neodymium iron boron magnet with a residual magnetism of 0.1 - 0.2 T (Tesla).

[0041] As a preferred embodiment of the present invention, the bench vice is an ordinary bench vice, the drill press is an ordinary drill press, and the handheld grinding wheel cutting machine is a commercially available ordinary handheld grinding machine.

[0042] As a preferred embodiment of the present invention, the purities of ammonium chloride, phosphoric acid, and calcium chloride are analytical pure, and the conductivity of the pure water is 18 microsiemens.

[0043] As a preferred embodiment of the present invention, the magnesium standard solution and the aluminum standard solution are certified reference samples (standard solutions), and the purity of the high-purity aluminum is greater than 99.98%.

[0044] As a preferred embodiment of the present invention, the inductively coupled plasma atomic emission spectrometer complies with the provisions of GB / T36244 - 2018.

[0045] The beneficial effects of the present invention are as follows:

[0046] Since the present invention uses a grinding wheel to cut the iron sheet layer, the peeling speed is fast.

[0047] Since the present invention does not use a solvent to dissolve the calcium core, a block calcium core sample can be obtained. A cutting powder collection box with a magnet is used to collect cutting powder, so the iron loss when the iron layer is peeled off is extremely low. Magnesium and aluminum are determined by inductively coupled plasma atomic emission spectrometry and corresponding deductions are made from the results of gas volumetric method determination. Therefore, the measurement result of elemental calcium is not affected by magnesium and aluminum. The gas volumetric method is used to determine the calcium content, and no hydrogen is generated when compounded calcium reacts with phosphoric acid, so that elemental calcium and compounded calcium can be distinguished.

[0048] Therefore, the present invention has the characteristics of fast iron scale stripping speed, ability to obtain block calcium core samples, extremely low iron loss when stripping the iron scale, elimination of the influence of magnesium and aluminum on the elemental calcium measurement results, and ability to distinguish elemental calcium from compound calcium. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention will be further described below with reference to the accompanying drawings.

[0050] Figure 1 It is a schematic structural diagram of the grinding fixture of the present invention;

[0051] Figure 2 It is a schematic structural diagram of the grinding powder collecting baffle box in the present invention;

[0052] Figure 3 It is a structural schematic diagram of the hydrogen measuring device in the present invention.

[0053] In the picture:

[0054] 1; rubber stopper, 2; connecting rod for sample tube, 3; sample tube, 4; conical flask, 5; constant temperature circulating water, 6; phosphoric acid solution, 7; outlet, 8; constant temperature water tank, 9; three-way piston, 10; first silicone connecting tube, 11; gas measuring tube, 12; second silicone connecting tube, 13; level bottle. DETAILED DESCRIPTION

[0055] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 making any creative efforts shall fall within the scope of protection of the present invention.

[0056] In the description of the present invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "around" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0057] As Figures 1 - 3 shown, a method for measuring the amount of calcium wire and elemental calcium in a seamless solid calcium wire, the measurement method comprising the following steps:

[0058] Step 1: Prepare a grinding fixture and a grinding powder collection box

[0059] Step 2: Prepare a hydrogen measuring device

[0060] Step 3: Use a cutting machine to remove the two ends of the seamless solid calcium wire sample, and then divide it into two equal segments. From one of the segments, cut a 15-20 mm sample block at each end, obtaining a total of 2 sample blocks; weigh the 2 sample blocks together, and record it as ms

[0061] Step 4: Place the 2 sample blocks in the arc clamping groove of the grinding fixture, align the end face of the sample block with the end face of the grinding fixture, place the front flat plate of the grinding powder collection box under the grinding fixture, clamp the grinding fixture with a bench vise, seal a magnet with a self-sealing plastic bag, and place it at the connection between the grinding fixture and the grinding powder collection box so that the magnet simultaneously attracts the grinding fixture and the grinding powder collection box. Use a hand-held abrasive wheel cutting machine to cut the iron sheet layer of the sample block along the axis. When one side of the iron sheet layer is cut through, turn the sample block 180° along the circumference of the sample, continue to clamp the 2 sample blocks with a bench vise and cut the iron sheet layer until the iron sheet layer is cut through; take out the sample block from the fixture and separate the calcium core from the iron sheet layer

[0062] Step 5: Quickly drill calcium chips from the two calcium cores with a drill press, collect 0.1-0.2 g of calcium chips below 0.5 mm on the surface of each, mix them, quickly weigh 0.15-0.20 g accurately to 0.0001 g, record it as msCa (g), and place it in the sample tube 3. Place the sample tube 3 together with the calcium chip sample on the sample tube connecting rod 2 on the rubber stopper 1 of the conical flask 4. Add 10-20 mL of phosphoric acid with a concentration of 50 g / L to the reaction flask, install the reaction flask stopper and connect the gas measuring device. Keep the three-way piston 9 in the three-way state of the atmosphere, the conical flask 4 and the gas burette 11. Keep the horizontal plane of the leveling flask 13, the horizontal of the gas burette 11 and the 0 scale line of the gas burette 11 in the same plane. Turn the three-way piston 9 to connect the gas burette 11 and the conical flask 4, cut off from the atmosphere, move the leveling flask 13 to a lower position, tilt the reaction flask to pour out the sample in the sample tube 3 to ensure that the aluminum chip sample is completely poured out. Shake the conical flask to make the phosphoric acid in the conical flask 4 enter the sample tube 3 to ensure that all the loaded aluminum chips react fully with the phosphoric acid. After the reaction is complete, cool the conical flask 4 to room temperature with running water at room temperature, and read the volume reading on the gas burette 11, record it as Vs (mL);

[0063] Weigh 0.10 g of high-purity aluminum chips accurately to 0.0001 g, denoted as \(m_{sAl}\) (g), and place them in the sample tube 3. Put the sample tube 3 together with the sample on the sample tube connecting rod 2 on the rubber stopper 1 of the conical flask 4. Add 20 - 30 mL of phosphoric acid with a concentration of 50 g / L to the conical flask 4, install the stopper of the conical flask 4 and connect the gas measuring device. Keep the three-way piston 9 in the three-way state of the atmosphere, the conical flask 4 and the gas burette 11. Keep the water level of the leveling flask 13, the level of the gas burette 11 and the 0 scale line of the gas burette 11 in the same plane. Turn the three-way piston 9 to connect the gas burette 11 and the conical flask 4, and cut off from the atmosphere. Move the leveling flask 13 to a lower position, tilt the conical flask 4 to pour out the sample in the sample tube 3, ensure that the aluminum chip sample is completely poured out, shake the conical flask so that the phosphoric acid in the conical flask 4 enters the sample tube 3, ensure that all the loaded aluminum chips react fully with the phosphoric acid. After the reaction is complete, cool the conical flask 4 to room temperature with running water at room temperature, and read the volume reading on the gas burette 11, denoted as \(V\) Al (mL). The total amount \(W_{CaT}\%\) of calcium, magnesium and aluminum in the form of elemental calcium is calculated according to formula (Ⅰ).

[0064]

[0065] Step 6. Separation of grinding powder

[0066] Transfer the grinding fixture, the grinding powder collection box and the magnet together to a clean A4 copy paper. Remove the magnet on the grinding fixture and the grinding powder collection box. Carefully collect all the grinding powder on the grinding powder collection box and the grinding fixture onto the clean copy paper. Use the originally sealed magnet to pick up the grinding powder placed on the clean copy paper, and discard the grinding powder on the copy paper that cannot be picked up by the magnet. Open the self-sealing plastic bag, take out the magnet, and transfer all the iron powder outside the plastic bag onto the copy paper. Repeat the suction selection operation as described above once to obtain the grinding iron powder

[0067] Step 7. Place the grinding iron powder and 4 iron sheet blocks in a 100 mL glass beaker, add 10 mL of ammonium chloride solution with a concentration of 100 g / L, soak for 5 min. Place a magnet at the bottom of the beaker, pour out the ammonium chloride completely by decantation, then wash the iron powder and iron sheets 3 times with pure water and dry them with hot air. Weigh the mass of the iron powder and iron sheets, denoted as \(m_{Fe}\). The calculation of the calcium wire amount is carried out according to formula (Ⅱ).

[0068]

[0069] Step 8. Determination of aluminum and magnesium

[0070] 1). Preparation of the sample solution

[0071] After the measurement of the hydrogen gas volume is completed, transfer the solution in the conical flask 4 to a 100 mL volumetric flask. Wash the conical flask (4) with 2 - 3 mL of pure water, transfer the washing liquid into the volumetric flask, wash 3 - 4 times, dilute to the mark with pure water, and shake well.

[0072] 2) Preparation of calibration curve solutions

[0073] Take 7 100 mL volumetric flasks. Add 18 mL of CaCl2 solution (10 mg Ca / mL) and 10 mL of phosphoric acid with a concentration of 50 g / L to each volumetric flask. Then, add 0.0, 0.2, 0.5, 1.0, 2.0, 3.0, 5.0 mL of aluminum standard solution (1.0 mg Al / mL) and magnesium standard solution (1.0 mg Mg / mL) respectively, dilute to the mark with pure water, and shake well.

[0074] 3) Measurement

[0075] On an inductively coupled plasma atomic emission spectrometer (ICP - OES), measure under the optimized working conditions. First, measure the calibration curve standard solutions, and establish calibration curves of spectral intensity versus the amounts of magnesium and aluminum with the amounts of magnesium and aluminum as the abscissa and the corresponding characteristic spectral intensities of magnesium and aluminum as the ordinate respectively. Then, measure the spectral intensity of the sample solution and read out the amounts of magnesium and aluminum on the inductively coupled plasma atomic emission spectrometer, denoted as mMg and mAl (mg), and calculate the mass fractions of magnesium and aluminum according to formulas (Ⅲ) and (Ⅳ).

[0076]

[0077]

[0078] Step Nine: Calculation of elemental calcium

[0079] Elemental calcium is calculated according to formula (Ⅴ)

[0080]

[0081] As a preferred embodiment of the present invention, the preparation method of the grinding fixture and the grinding powder collection box is as follows: Take a steel plate with a thickness of 1 mm and side lengths of 30 mm and 70 mm respectively, bend it into a semi-circular arc plate with a diameter of 12 mm with the midpoint of the length direction as the vertex, and then symmetrically bend the two sides of the semi-circular arc plate outward by 90 degrees so that the chord formed by the two bending points is parallel to the diameter line of the semi-circular arc, and the vertical line length from the chord line to the vertex of the semi-circular arc is greater than the radius of the semi-circular arc (6 mm) to obtain the grinding fixture. Take another steel plate with a thickness of 1 mm, a length of 110 mm and a width of 70 mm, cut off 20×20 squares at the two corners at one end, cut off a 15×10 rectangular block at the center of the other end, and cut off 20×10 rectangular blocks at the two corners, and bend the 100 mm long sides on both sides by 90 degrees and the 30 mm short side at the top by 90 degrees to obtain the grinding powder collection box.

[0082] As a preferred embodiment of the present invention, the hydrogen measuring device includes a reactor, a constant temperature water bath 8, a connecting pipe, a gas measuring tube 11 and a leveling bottle 13. The reactor includes a rubber stopper 1, a sample loading tube connecting rod 2, a sample loading tube 3, a conical flask 4 and a three-way piston 9. The rubber stopper 1 is located inside the mouth of the conical flask 4, the sample loading tube connecting rod 2 is arranged at the bottom of the rubber stopper 1, the sample loading tube 3 is arranged on the sample loading tube connecting rod 2. The sample loading tube 3 is a glass tube with one end open, its inner diameter is 15 mm and its depth is 10 mm. The axial direction of the sample loading tube 3 is parallel to the bottom surface of the rubber stopper 1. The constant temperature water bath 8 is provided with a circulating water inlet and outlet 7, and the constant temperature water bath 8 is filled with constant temperature circulating water 5. A first silica gel connecting tube 10 is arranged between the rubber stopper 1 and the gas measuring tube 11. The first silica gel connecting tube 10 penetrates through the rubber stopper 1, and a three-way piston 9 is arranged on the first silica gel connecting tube 10. A second silica gel connecting tube 12 is arranged between the gas measuring tube 11 and the leveling bottle 13. The volume of the constant temperature water bath 8 is large enough to accommodate the conical flask 4. The gas measuring tube 11 is a 150 mL graduated gas measuring tube 11 with a minimum scale of 0.2 mL, and the volume of the leveling bottle 13 is 1000 mL.

[0083] As a preferred embodiment of the present invention, the grinding powder is the powder and chips generated by the interaction between the equipment and the sample during the grinding and cutting process.

[0084] As a preferred embodiment of the present invention, the steel plate is made of ordinary carbon steel or low alloy steel.

[0085] As a preferred embodiment of the present invention, the magnet is a bar-shaped or circular neodymium iron boron magnet with a remanence of 0.1 - 0.2 T (Tesla).

[0086] As a preferred embodiment of the present invention, the bench vice is an ordinary bench vice, the drill press is an ordinary drill press, and the hand-held grinding wheel cutter is a commercially available ordinary hand-held grinding wheel machine.

[0087] As a preferred embodiment of the present invention, the purities of ammonium chloride, phosphoric acid, and calcium chloride are of analytical purity, and the conductivity of pure water is 18 microsiemens.

[0088] As a preferred embodiment of the present invention, the magnesium standard solution and the aluminum standard solution are certified reference materials (standard solutions), and the purity of high-purity aluminum is greater than 99.98%.

[0089] As a preferred embodiment of the present invention, the inductively coupled plasma atomic emission spectrometer complies with the provisions of GB / T 36244-2018.

[0090] Implement according to the above steps. For 3 pairs of specimens, each specimen is measured 2 times in parallel, and the recorded and calculated results are summarized in Table 1, the summary table of example records and results.

[0091] Table 1 Summary table of example records and results

[0092]

[0093] In the description of this specification, the descriptions referring to the terms "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0094] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

[0095] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0096] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and simple improvements made to the substantial content of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for determining the amount of calcium wire and elemental calcium in a seamless solid calcium wire, characterized in that the determination method comprises the following steps: Step 1: Prepare a grinding fixture and a grinding powder collection box; Step 2: Prepare a hydrogen measuring device; Step 3: Use a cutting machine to remove the two ends of the seamless solid calcium wire sample, and then divide it into two equal segments. From one of the segments, cut a 15-20 mm sample block at each end, obtaining a total of 2 sample blocks; weigh the mass of the 2 sample blocks together, denoted as ; Step 4: Place the 2 sample blocks in the arc clamping groove of the grinding fixture, align the end face of the sample block with the end face of the grinding fixture, place the front flat plate of the grinding powder collection box under the grinding fixture, clamp the grinding fixture with a bench vice, seal a magnet with a self-sealing plastic bag and place it at the connection between the grinding fixture and the grinding powder collection box, so that the magnet attracts both the grinding fixture and the grinding powder collection box at the same time. Use a hand-held abrasive wheel cutting machine to cut the iron sheet layer of the sample block along the axis. When one side of the iron sheet layer is cut through, rotate the sample block 180° along the circumference of the sample, continue to clamp the 2 sample blocks with the bench vice and cut the iron sheet layer until it is cut through, take out the sample block from the fixture and separate the calcium core from the iron sheet layer; Step 5: Quickly drill calcium chips from the two calcium cores with a drill press, collect 0.1-0.2 g of calcium chips below 0.5 mm from the surface layer of each, mix them, and quickly weigh 0.15-0.20 g accurately to 0.0001 g, denoted as Place it in the sample tube (3), put the sample tube (3) together with the calcium chip sample on the sample tube connecting rod (2) on the rubber stopper (1) of the conical flask (4), add 10-20 mL of phosphoric acid with a concentration of 50 g / L to the reaction flask, install the reaction flask stopper and connect the gas measuring device. Keep the three-way piston (9) in a three-way state of the atmosphere, the conical flask (4) and the gas burette (11). Keep the water level of the leveling flask (13), the level of the gas burette (11) and the 0 scale line of the gas burette (11) in the same plane. Turn the three-way piston (9) to connect the gas burette (11) and the conical flask (4), cut off from the atmosphere, move the leveling flask (13) to a lower position, tilt the reaction flask to pour out the sample in the sample tube (3), ensure that the aluminum chip sample is poured out completely, shake the conical flask so that the phosphoric acid in the conical flask (4) enters the sample tube (3), ensure that all the loaded aluminum chips react fully with the phosphoric acid. After the reaction is complete, cool the conical flask (4) to room temperature with running water at room temperature, read the volume reading on the gas burette (11), denoted as ; Weigh 0.10 g of high-purity metal aluminum chips accurately to 0.0001 g, denoted as Place it in the sample loading tube (3), and place the sample loading tube (3) together with the sample on the sample loading tube connecting rod (2) on the rubber stopper (1) of the conical flask (4). Add 20 - 30 mL of phosphoric acid with a concentration of 50 g / L to the conical flask (4). Install the stopper of the conical flask (4) and connect the gas measuring device. Keep the three-way piston (9) in the three-way state of the atmosphere, the conical flask (4), and the gas measuring tube (11). Keep the water level of the leveling flask (13), the level of the gas measuring tube (11), and the 0 scale line of the gas measuring tube (11) in the same plane. Turn the three-way piston (9) to connect the gas measuring tube (11) and the conical flask (4), and cut off from the atmosphere. Move the leveling flask (13) to a lower position, tilt the conical flask (4) to pour out the sample in the sample loading tube (3), ensure that all the aluminum chip samples are poured out, shake the conical flask so that the phosphoric acid in the conical flask (4) enters the sample loading tube (3), ensure that all the loaded aluminum chips react fully with the phosphoric acid. After the reaction is complete, cool the conical flask (4) to room temperature with running water at room temperature, read the volume reading on the gas measuring tube (11), and record it as , the calculation of the total amount WCaT% of calcium, magnesium, and aluminum in elemental form in terms of elemental calcium is carried out according to the formula as follows: Step Six: Separation of Grinding Powder Transfer the grinding fixture, the grinding powder collection box, and the magnet together to a clean A4 copy paper. Remove the magnet on the grinding fixture and the grinding powder collection box. Carefully collect all the grinding powder on the grinding powder collection box and the grinding fixture onto the clean copy paper. Use the originally sealed magnet to absorb the grinding powder placed on the clean copy paper, discard the grinding powder on the copy paper that cannot be absorbed by the magnet. Open the self-sealing plastic bag, take out the magnet, and transfer all the iron powder outside the plastic bag onto the copy paper. Repeat the suction selection operation as described above once to obtain the grinding iron powder; Step Seven: Place the grinding iron powder and 4 iron sheet blocks in a 100 mL glass beaker, add 10 mL of ammonium chloride solution with a concentration of 100 g / L, soak for 5 minutes. Place a magnet at the bottom of the beaker, pour out the ammonium chloride completely by decantation, then wash the iron powder and iron sheets with pure water 3 times, and dry them with hot air. Weigh the mass of the iron powder and iron sheets, and record it as , the calculation of the calcium wire amount is carried out according to the formula as follows: Step Eight: Determination of Aluminum and Magnesium 1. Preparation of sample solution After the measurement of the hydrogen gas volume is completed, transfer the solution in the conical flask (4) to a 100 mL volumetric flask. Wash the conical flask (4) with 2 - 3 mL of pure water, transfer the washing solution into the volumetric flask, wash 3 - 4 times, and dilute to the mark with pure water, then shake well; 2. Preparation of calibration curve solution Take 7 100-mL volumetric flasks and add to each flask 18 mL of the solution and 10 mL of phosphoric acid with a concentration of 50 g / L. Then, add 0.0, 0.2, 0.5, 1.0, 2.0, 3.0, and 5.0 mL of aluminum standard solution and magnesium standard solution respectively, dilute to the mark with pure water, and shake well; 3. Measurement On the inductively coupled plasma atomic emission spectrometer, measure according to the optimized working conditions. First, measure the calibration curve standard solution, and establish the calibration curves of spectral intensity vs. the amounts of magnesium and aluminum with the amounts of magnesium and aluminum as the abscissa and the corresponding characteristic spectral intensities of magnesium and aluminum as the ordinate respectively. Then, measure the spectral intensity of the sample solution and read out the amounts of magnesium and aluminum on the inductively coupled plasma atomic emission spectrometer; Among them, the formula and in which WMg% is the mass fraction of magnesium, and mAl% is the mass fraction of aluminum, is the mass of magnesium, is the mass of aluminum; Step Nine: Calculation of elemental calcium Elemental calcium is calculated according to formula (V) (V) 。 2. The method for measuring the amount of seamless solid calcium wire and elemental calcium according to claim 1, characterized in that, The preparation method of the grinding fixture and the grinding powder collection box is as follows: Take a steel plate with a thickness of 1 mm and side lengths of 30 mm and 70 mm respectively, bend it into a semi-circular arc plate with a diameter of 12 mm with the midpoint of the length direction as the vertex, and then symmetrically bend the two sides of the semi-circular arc plate outward by 90 degrees so that the chord formed by the two bending points is parallel to the diameter line of the semi-circular arc, and the perpendicular distance from the chord line to the vertex of the semi-circular arc is greater than the radius of the semi-circular arc (6 mm) to obtain the grinding fixture. Take another steel plate with a thickness of 1 mm, a length of 110 mm and a width of 70 mm, cut off 20×20 squares at the two corners at one end, cut off a 15×10 rectangle at the center of the other end, and cut off 20×10 rectangles at the two corners. Bend the 100 mm long sides on both sides by 90 degrees and bend the 30 mm short side at the top by 90 degrees to obtain the grinding powder collection box.

3. The method for determining the amount of calcium wire and elemental calcium in the seamless solid calcium wire according to claim 1, characterized in that, The hydrogen gas measuring device includes a reactor, a constant temperature water bath (8), a connecting pipe, a gas measuring tube (11) and a leveling bottle (13). The reactor includes a rubber stopper (1), a sample loading tube connecting rod (2), a sample loading tube (3), a conical flask (4) and a three-way piston (9). The rubber stopper (1) is located inside the mouth of the conical flask (4). The sample loading tube connecting rod (2) is arranged at the bottom of the rubber stopper (1). The sample loading tube (3) is arranged on the sample loading tube connecting rod (2). The sample loading tube (3) is a glass tube with one end open, and the axis of the sample loading tube (3) is parallel to the bottom surface of the rubber stopper (1). The inside of the conical flask (4) is filled with phosphoric acid solution (6). The constant temperature water bath (8) is provided with a circulating water inlet and outlet (7), and the constant temperature water bath (8) is filled with constant temperature circulating water (5). A first silica gel connecting tube (10) is arranged between the rubber stopper (1) and the gas measuring tube (11). The first silica gel connecting tube (10) penetrates through the rubber stopper (1), and a three-way piston (9) is arranged on the first silica gel connecting tube (10). A second silica gel connecting tube (12) is arranged between the gas measuring tube (11) and the leveling bottle (13). The volume of the constant temperature water bath (8) is large enough to accommodate the conical flask (4).

4. The method for determining the amount of calcium wire and elemental calcium in the seamless solid calcium wire according to claim 1, characterized in that, The grinding powder is the powder and chips generated by the interaction between the equipment and the sample during the grinding and cutting process.

5. The method for determining the amount of calcium wire and elemental calcium in the seamless solid calcium wire according to claim 2, characterized in that, The steel plate is made of one of plain carbon steel and low alloy steel.

6. The method for determining the amount of calcium wire and elemental calcium in the seamless solid calcium wire according to claim 1, wherein The magnet is a bar-shaped or circular neodymium iron boron magnet with a residual magnetism of 0.1 - 0.2 T.

7. The method for determining the amount of calcium wire and elemental calcium in the seamless solid calcium wire according to claim 1, characterized in that, The bench vice is an ordinary bench vice, the drill press is an ordinary drill press, and the hand-held grinding wheel cutting machine is a commercially available ordinary hand-held grinding wheel machine.

8. The method for determining the amount of calcium wire and elemental calcium in the seamless solid calcium wire according to claim 1, characterized in that, The purities of the ammonium chloride, phosphoric acid, and calcium chloride are of analytical purity, and the conductivity of the pure water is 18 microsiemens.

9. The method for determining the amount of calcium wire and elemental calcium in the seamless solid calcium wire according to claim 1, characterized in that, The magnesium standard solution and the aluminum standard solution are certified reference materials, and the purity of the high-purity metallic aluminum chips is greater than 99.98%.

10. The method for measuring the amount of calcium wire and elemental calcium in the seamless solid calcium wire according to claim 1, characterized in that, The inductively coupled plasma atomic emission spectrometer complies with the provisions of GB / T 36244-2018.

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