A method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron

Abstract

The present application relates to a method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron, belonging to the technical field of analysis and detection. The method respectively obtains the total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested, the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested, and the content W3 of all iron ions in the aluminum slag ball sample containing elemental iron to be tested, and then obtains the elemental aluminum content W4 in the aluminum slag ball sample containing elemental iron to be tested according to W1, W2 and W3 in the aluminum slag ball sample containing elemental iron to be tested. The method can effectively avoid the influence of elemental iron in the aluminum slag ball, obtain the real metal aluminum content, and the detection result is highly accurate.

Description

Technical Field

[0001] The present application relates to the technical field of analysis and detection, and in particular to a method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron. Background Art

[0002] Aluminum slag balls are mainly made by physically mixing and pressing aluminum slag generated during the smelting process and some other components. In addition to the functions of deoxidation, slag making and covering of molten steel, aluminum slag balls can also reduce dust emissions in steelmaking production and are widely used in the field of automobile plate production. The effective deoxidation component in aluminum slag balls is metallic aluminum. The metallic aluminum content in aluminum slag balls is about 40%-65%, which is relatively high. The metallic aluminum content is a major indicator for measuring the quality of aluminum slag balls.

[0003] At present, there is no report on the determination of the content of metallic aluminum in aluminum slag balls. There are only methods for determining the content of metallic aluminum in materials such as aluminum slag, high-aluminum slow-release deoxidizer, AD powder, slag conditioning agent, and modifier in related fields, such as the ferric chloride dissolution-complexometric titration method or ICP method for determining the content of metallic aluminum in aluminum slag. Compared with aluminum slag balls, the content of metallic aluminum in these materials is relatively low, generally not exceeding 40%. At the same time, the above-mentioned method for detecting the content of elemental aluminum in aluminum-containing samples has the problem of poor accuracy of the test results due to the influence of elemental iron. Summary of the invention

[0004] The present application provides a method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron, so as to solve the technical problem of poor accuracy of detection results caused by the influence of elemental iron in existing methods for detecting the content of elemental aluminum in aluminum-containing samples.

[0005] In a first aspect, the present application provides a method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron, the method comprising:

[0006] Performing a first titration analysis on the aluminum slag ball sample containing elemental iron to be tested, to obtain a total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested;

[0007] The aluminum slag ball sample containing elemental iron to be tested is subjected to a second titration analysis to obtain the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested;

[0008] Perform a third titration analysis on the aluminum slag ball sample containing elemental iron to be tested, and obtain the content W3 of all iron ions in the aluminum slag ball sample containing elemental iron to be tested;

[0009] According to W1, W2 and W3 in the aluminum slag ball sample containing elemental iron to be tested, the elemental aluminum content W4 in the aluminum slag ball sample containing elemental iron to be tested is obtained.

[0010] Furthermore, the process parameters of the first titration analysis detection include: the titration reagent is a potassium dichromate standard solution titration solution, the indicator is a sodium diphenylamine sulfonate solution, and the color of the titration endpoint solution is purple.

[0011] Further, the aluminum slag ball sample containing elemental iron to be tested is subjected to a first titration analysis to obtain the total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested, specifically comprising:

[0012] Dissolving the aluminum slag ball sample containing elemental iron to be tested in a trivalent ferrous ion solution to perform a first oxidation-reduction reaction to obtain a first ferrous ion-containing solution;

[0013] The first ferrous ion-containing solution is titrated with a potassium dichromate standard solution to perform a first titration analysis to obtain the total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested.

[0014] Furthermore, the trivalent iron ion solution includes at least one of a ferric sulfate ion solution and a ferric nitrate ion solution.

[0015] Furthermore, the process parameters of the second titration analysis detection include: the titration reagent is a potassium dichromate standard solution titration solution, the indicator is a sodium diphenylamine sulfonate solution, and the color of the titration endpoint solution is purple.

[0016] Further, the aluminum slag ball sample containing elemental iron to be tested is subjected to a second titration analysis to obtain the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested, specifically comprising:

[0017] Dissolving the aluminum slag ball sample containing elemental iron to be tested in sulfuric and phosphoric acid mixture to obtain an aluminum slag ball sample solution containing trivalent iron ions;

[0018] Adding stannous halide and titanium trihalide to the aluminum slag ball sample solution containing trivalent ferrous ions to carry out a second redox reaction to obtain a second ferrous ion-containing solution;

[0019] The second ferrous ion-containing solution is titrated with a potassium dichromate standard solution to perform a second titration analysis to obtain the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested.

[0020] Further, the stannous halide includes at least one of stannous chloride, stannous bromide and stannous iodide; and the titanium trihalide includes at least one of titanium trichloride and titanium tribromide.

[0021] Further, the aluminum slag ball sample containing elemental iron to be tested is subjected to a third titration analysis to obtain the content W3 of all iron ions in the aluminum slag ball sample containing elemental iron to be tested, specifically comprising:

[0022] The elemental iron in the aluminum slag ball sample containing elemental iron to be tested is separated by an iodine-ethanol method, and then stannous halide and titanium trihalide are added to carry out a third oxidation-reduction reaction to obtain a third ferrous ion-containing solution;

[0023] The third ferrous ion-containing solution is titrated with a potassium dichromate standard solution to perform a third titration analysis to obtain the content W3 of all iron ions in the aluminum slag ball sample containing elemental iron to be tested.

[0024] Furthermore, the determination range of elemental aluminum in the aluminum slag ball sample containing elemental iron to be tested is 40% to 70%.

[0025] Further, the content of elemental aluminum in the aluminum slag ball sample containing elemental iron to be tested is obtained according to W1, W2 and W3 in the aluminum slag ball sample containing elemental iron to be tested, specifically comprising:

[0026] According to W1, W2 and W3 in the aluminum slag ball sample containing elemental iron to be tested, the elemental aluminum content W4 in the aluminum slag ball sample containing elemental iron to be tested is obtained by expression (1);

[0027] The expression (1):

[0028] W4 = W1 - (W2 - W3);

[0029] In the expression (1), W1 is the total content of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested; W2 is the content of all iron elements in the aluminum slag ball sample containing elemental iron to be tested; W3 is the content of all iron ions in the aluminum slag ball sample containing elemental iron to be tested; W4 is the content of elemental aluminum in the aluminum slag ball sample containing elemental iron to be tested.

[0030] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0031] The embodiment of the present application provides a method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron. The method obtains the total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested, the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested, and the content W3 of all iron ions in the aluminum slag ball sample containing elemental iron to be tested, respectively, by performing a first titration analysis test, a second titration analysis test, and a third titration analysis test, and then obtains the elemental aluminum content W4 in the aluminum slag ball sample containing elemental iron to be tested according to W1, W2, and W3 in the aluminum slag ball sample containing elemental iron to be tested. The method can effectively avoid the influence of elemental iron in the aluminum slag ball, obtain the true metal aluminum content, and the detection result is highly accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0034] Figure 1 A schematic flow chart of a method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0036] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0037] Aluminum slag balls are mainly made by physically mixing and pressing aluminum slag generated during the smelting process and some other components. In addition to the functions of deoxidation, slag making and covering of molten steel, aluminum slag balls can also reduce dust emissions in steelmaking production and are widely used in the field of automobile plate production. The effective deoxidation component in aluminum slag balls is metallic aluminum. The metallic aluminum content in aluminum slag balls is about 40%-65%, which is relatively high. The metallic aluminum content is a major indicator for measuring the quality of aluminum slag balls.

[0038] At present, there is no report on the determination of the content of metallic aluminum in aluminum slag balls. There are only methods for determining the content of metallic aluminum in materials such as aluminum slag, high-aluminum slow-release deoxidizer, AD powder, slag conditioning agent, and modifier in related fields, such as the ferric chloride dissolution-complexometric titration method or ICP method for determining the content of metallic aluminum in aluminum slag. Compared with aluminum slag balls, the content of metallic aluminum in these materials is relatively low, generally not exceeding 40%. At the same time, the above-mentioned method for detecting the content of elemental aluminum in aluminum-containing samples has the problem of poor accuracy of the test results due to the influence of elemental iron.

[0039] The technical solution provided by the embodiment of the present invention is to solve the above technical problems, and the overall idea is as follows:

[0040] In the first aspect, the present application provides a method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron, such as Figure 1 As shown, the method includes:

[0041] Performing a first titration analysis on the aluminum slag ball sample containing elemental iron to be tested, to obtain a total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested;

[0042] The aluminum slag ball sample containing elemental iron to be tested is subjected to a second titration analysis to obtain the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested;

[0043] Perform a third titration analysis on the aluminum slag ball sample containing elemental iron to be tested, and obtain the content W3 of all iron ions in the aluminum slag ball sample containing elemental iron to be tested;

[0044] According to W1, W2 and W3 in the aluminum slag ball sample containing elemental iron to be tested, the elemental aluminum content W4 in the aluminum slag ball sample containing elemental iron to be tested is obtained.

[0045] The embodiment of the present application provides a method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron. The method obtains the total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested, the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested, and the content W3 of all iron ions in the aluminum slag ball sample containing elemental iron to be tested, respectively, by performing a first titration analysis test, a second titration analysis test, and a third titration analysis test, and then obtains the elemental aluminum content W4 in the aluminum slag ball sample containing elemental iron to be tested according to W1, W2, and W3 in the aluminum slag ball sample containing elemental iron to be tested. The method can effectively avoid the influence of elemental iron in the aluminum slag ball, obtain the true metal aluminum content, and the detection result is highly accurate.

[0046] In the present application, in some specific embodiments, the preparation process of the aluminum slag ball sample containing elemental iron to be tested can be as follows: the aluminum slag ball sample containing elemental iron to be tested is crushed, ground on a vibration mill for 30 seconds, passed through a 0.5 mm sieve, and the sieve material is repeatedly ground until all of it passes through a 0.5 mm sieve. Weigh three portions of 0.2 g of the aluminum slag ball sample as sample 1, sample 2, and sample 3 for standby use.

[0047] As an implementation of an embodiment of the present application, the process parameters of the first titration analysis detection include: the titration reagent is a potassium dichromate standard solution titration solution, the indicator is a sodium diphenylamine sulfonate solution, and the color of the titration endpoint solution is purple.

[0048] In the present application, potassium dichromate standard solution is used to titrate the total amount of ferrous ions in the solution, that is, to titrate the total amount of metallic aluminum and metallic iron. From the reaction equations of metallic iron and metallic aluminum with potassium dichromate, it can be seen that 2 mol of metallic iron and 2 mol of metallic aluminum both consume 1 mol of potassium dichromate.

[0049] The relevant reactions are as follows:

[0050] 2Fe+4Fe 3+ ==6Fe 2+

[0051] 2Al+6Fe 3+ ==6Fe 2+ +2Al 3+

[0052] 6Fe 2+ +Cr2O7 2- +14H + ==6Fe 3+ +2Cr 3+ +7H2O

[0053] As an implementation method of an embodiment of the present application, the aluminum slag ball sample containing elemental iron to be tested is subjected to a first titration analysis to obtain the total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested, specifically comprising:

[0054] Dissolving the aluminum slag ball sample containing elemental iron to be tested in a trivalent ferrous ion solution to perform a first oxidation-reduction reaction to obtain a first ferrous ion-containing solution;

[0055] The first ferrous ion-containing solution is titrated with a potassium dichromate standard solution to perform a first titration analysis to obtain the total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested.

[0056] In the present application, in some specific embodiments, the above-mentioned first titration analysis detection process can be as follows: the aluminum slag ball sample 1 containing elemental iron to be tested is placed in a 300mL conical flask, 100mL of ferric sulfate solution (200g / L) is added, the crucible cover is immediately covered, and the sample is heated on a low-temperature electric furnace for 90 minutes to dissolve the sample, and then removed. The crucible cover is replaced with a rubber stopper, and the sample is cooled to room temperature with running water. The rubber stopper is removed, and the solution is transferred to a 250mL volumetric flask, and the volume is fixed and shaken well.

[0057] Take 50mL of solution, add 20mL of sulfuric acid and phosphoric acid mixture (1+1+5, "1+1+5" is the volume ratio, specifically understood as 1 volume of sulfuric acid, 1 volume of phosphoric acid and 5 volumes of water), 5 drops of sodium diphenylamine sulfonate solution (2g / L), and titrate with potassium dichromate standard titration solution c1 (0.015mol / L) until purple is the end point, and record the reading V 合 .

[0058] The metal aluminum content is used to express the total amount of metal iron and metal aluminum. The calculation formula is as follows:

[0059]

[0060] In formula (2): w 合 is the total amount of metallic iron and metallic aluminum expressed as the metallic aluminum content, %; c1 is the concentration of potassium dichromate standard solution, mol / L; V 合 is the total volume of potassium dichromate standard solution consumed by the metallic aluminum and metallic iron in the sample, mL; m is the sample weight, g.

[0061] In the present application, the content of divalent iron in the aluminum slag ball sample containing elemental iron to be tested is very low, and the amount of divalent iron dissolved in a slightly acidic solution such as ferric sulfate is very small, so the impact on the test result is also very small and can be ignored.

[0062] As an implementation of an embodiment of the present application, the trivalent iron ion solution includes at least one of a ferric sulfate ion solution and a ferric nitrate ion solution.

[0063] As an implementation method of an embodiment of the present application, the process parameters of the second titration analysis detection include: the titration reagent is a potassium dichromate standard solution titration solution, the indicator is a sodium diphenylamine sulfonate solution, and the color of the titration endpoint solution is purple.

[0064] As an implementation method of the present application, the aluminum slag ball sample containing elemental iron to be tested is subjected to a second titration analysis to obtain the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested, specifically including:

[0065] Dissolving the aluminum slag ball sample containing elemental iron to be tested in sulfuric and phosphoric acid mixture to obtain an aluminum slag ball sample solution containing trivalent iron ions;

[0066] Adding stannous halide and titanium trihalide to the aluminum slag ball sample solution containing trivalent ferrous ions to carry out a second redox reaction to obtain a second ferrous ion-containing solution;

[0067] The second ferrous ion-containing solution is titrated with a potassium dichromate standard solution to perform a second titration analysis to obtain the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested.

[0068] In the present application, in some specific embodiments, the above-mentioned second titration analysis detection process can be as follows: the aluminum slag ball sample 2 containing elemental iron to be tested is placed in a 300mL conical flask, a little water is blown to disperse the sample, 5mL potassium fluoride solution (200g / L) and 15mL sulfuric acid and phosphorus mixed acid (5+3, "5+3" is a volume ratio, specifically understood as 5 volumes of sulfuric acid and 3 volumes of phosphoric acid mixed.), shake well, place it on an electric furnace plate and heat it to boiling at a low temperature, add a few drops of concentrated nitric acid, dissolve it until smoking, continue to heat it until thick white smoke rises, remove it, cool it, blow the bottle wall with water, add 15mL hydrochloric acid (1+1, "1+1" is a volume ratio, specifically understood as 1 volume Mix concentrated hydrochloric acid and 1 volume of water. ), immediately add stannous chloride solution (60g / L) to reduce to light yellow, add 50mL hot water, heat the solution to a slight boil for 1-2 minutes, remove, cool to about 50°C, add 15-20 drops of sodium tungstate solution (250g / L), add titanium trichloride solution (10g / L) until blue appears, add potassium dichromate standard solution c2 (0.004166mol / L) until blue disappears, add 4-6 drops of sodium diphenylamine sulfonate solution (2g / L), titrate with potassium dichromate standard solution c2 (0.004166mol / L) to a stable bright purple as the end point, and record the reading V1.

[0069] As an implementation method of an embodiment of the present application, the aluminum slag ball sample containing elemental iron to be tested is subjected to a third titration analysis to obtain the content W3 of all iron ions in the aluminum slag ball sample containing elemental iron to be tested, specifically including:

[0070] The elemental iron in the aluminum slag ball sample containing elemental iron to be tested is separated by an iodine-ethanol method, and then stannous halide and titanium trihalide are added to carry out a third oxidation-reduction reaction to obtain a third ferrous ion-containing solution;

[0071] The third ferrous ion-containing solution is titrated with a potassium dichromate standard solution to perform a third titration analysis to obtain the content W3 of all iron ions in the aluminum slag ball sample containing elemental iron to be tested.

[0072] In the present application, in some specific embodiments, the third titration analysis detection process can be as follows: the aluminum slag ball sample 3 containing elemental iron to be tested is placed in a 300 mL conical flask, 50 mL of iodine-ethanol solution is added, the bottle mouth is plugged with a rubber stopper, the conical flask is placed in an oscillating agitator, and oscillated at room temperature for 50 minutes. Filter with medium-speed filter paper, wash the conical flask 5 times with anhydrous ethanol, precipitate 5 times, and discard the filtrate. The filter paper and the precipitate are placed in a platinum crucible, ashed at 550°C, calcined at 800°C for 20 minutes, and taken out for cooling. Add 2g of boric acid and sodium carbonate mixed flux (1+2, "1+2" ​​is the mass ratio, specifically understood as 1 mass part of boric acid and 2 mass parts of sodium carbonate mixed), calcine at 1000℃ for 20 minutes, take out and cool, put into a 250mL beaker, add 50mL of hydrochloric acid (1+1, "1+1" is the volume ratio, specifically understood as 1 volume of concentrated hydrochloric acid and 1 volume of water mixed.), heat at low temperature to completely dissolve the melt, take out and cool to room temperature, and wash out the crucible. Immediately add stannous chloride solution (60g / L) to reduce it to light yellow, add 30mL of hot water, heat the solution to a slight boil for 1-2 minutes, remove it, cool it to about 50°C, add 15-20 drops of sodium tungstate solution (250g / L), add titanium trichloride solution (10g / L) until blue appears, add potassium dichromate standard solution c2 (0.004166mol / L) until the blue disappears, add 4-6 drops of sodium diphenylamine sulfonate solution (2g / L), and titrate with potassium dichromate standard solution c2 (0.004166mol / L) to a stable bright purple as the end point, and record the reading V2.

[0073] In the present application, the amount of metallic iron is obtained by indirect subtraction. Sample 2 is used to determine the total iron content in the sample, which is the sum of metallic iron, divalent iron and trivalent iron. Sample 3 is used to determine the amount of other iron in the sample except metallic iron (metallic iron is separated by iodine-ethanol, and other iron is in the precipitate). The metallic iron content is obtained by subtraction, that is, the total iron content minus the amount of other iron. In some specific embodiments, the calculation of metallic iron in the sample

[0074] The calculation formula of the metallic iron content in the sample is as follows:

[0075]

[0076] In formula (3): w MFe is the content of metallic iron in the sample, %; c2 is the concentration of potassium dichromate standard solution, mol / L; V1 is the volume of potassium dichromate standard solution consumed by the total iron in sample 2, mL; V2 is the volume of potassium dichromate standard solution consumed by the iron content in the precipitate of sample 3, mL; m is the sample weight, g.

[0077] As an implementation method of an example of the present application, the determination range of elemental aluminum in the aluminum slag ball sample containing elemental iron to be tested is 40% to 70%.

[0078] Compared with aluminum slag balls, the aluminum slag, high aluminum slow-release deoxidizer, AD powder, slag conditioning agent, modifier and other materials have a relatively low aluminum content, generally not exceeding 40%. The detection method provided in the embodiment of the present application is applicable to the determination of elemental aluminum in the aluminum slag ball sample containing elemental iron to be tested with an elemental aluminum content ranging from 40% to 70%. In the present application, the content range of 40% to 70% should be understood as the mass fraction of elemental aluminum in the aluminum slag ball sample containing elemental iron to be tested is 40% to 70%.

[0079] As an implementation method of an embodiment of the present application, the content of elemental aluminum in the aluminum slag ball sample containing elemental iron to be tested is obtained according to W1, W2 and W3 in the aluminum slag ball sample containing elemental iron to be tested, specifically including:

[0080] According to W1, W2 and W3 in the aluminum slag ball sample containing elemental iron to be tested, the elemental aluminum content W4 in the aluminum slag ball sample containing elemental iron to be tested is obtained by expression (1);

[0081] The expression (1):

[0082] W4 = W1 - (W2 - W3);

[0083] In the expression (1), W1 is the total content of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested; W2 is the content of all iron elements in the aluminum slag ball sample containing elemental iron to be tested; W3 is the content of all iron ions in the aluminum slag ball sample containing elemental iron to be tested; W4 is the content of elemental aluminum in the aluminum slag ball sample containing elemental iron to be tested.

[0084] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0085] Example 1

[0086] This example provides a method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron, the method comprising:

[0087] Step 1: Aluminum slag ball sample preparation

[0088] After the aluminum slag balls containing metallic iron were crushed, they were ground on a vibration mill for 30 seconds, passed through a 0.5 mm sieve, and the sieved material was repeatedly ground until all of them passed through the 0.5 mm sieve. Three samples of 0.2 g of aluminum slag balls were weighed and designated as sample 1, sample 2, and sample 3.

[0089] Step 2: Dissolution of ferrous sulfate - determination of the total amount of metallic aluminum and metallic iron in sample 1 by potassium dichromate titration

[0090] Place the aluminum slag ball sample 1 containing elemental iron to be tested in a 300mL conical flask, add 100mL of ferric sulfate solution (200g / L), immediately cover the crucible lid, heat on a low-temperature electric furnace for 90 minutes to dissolve the sample, and remove it. Replace the crucible lid with a rubber stopper and cool it to room temperature under running water. Remove the rubber stopper, transfer the solution to a 250mL volumetric flask, and shake it to volume.

[0091] Take 50mL of solution, add 20mL of sulfuric acid and phosphoric acid mixture (1+1+5, "1+1+5" is the volume ratio, specifically understood as 1 volume of sulfuric acid, 1 volume of phosphoric acid and 5 volumes of water), 5 drops of sodium diphenylamine sulfonate solution (2g / L), and titrate with potassium dichromate standard titration solution c1 (0.015mol / L) until purple is the end point, and record the reading V 合 .

[0092] The metal aluminum content is used to express the total amount of metal iron and metal aluminum. The calculation formula is as follows:

[0093]

[0094] In formula (2): w 合 is the total amount of metallic iron and metallic aluminum expressed as the metallic aluminum content, %; c1 is the concentration of potassium dichromate standard solution, mol / L; V 合 is the total volume of potassium dichromate standard solution consumed by the metallic aluminum and metallic iron in the sample, mL; m is the sample weight, g.

[0095] Step 3: Determination of total iron content in sample 2 by potassium dichromate titration

[0096] The aluminum slag ball sample 2 containing elemental iron to be tested is placed in a 300mL conical flask, a little water is blown to disperse the sample, 5mL potassium fluoride solution (200g / L) and 15mL sulfuric acid and phosphorus mixed acid (5+3, "5+3" is a volume ratio, specifically understood as a mixture of 5 volumes of sulfuric acid and 3 volumes of phosphoric acid) are added, shaken well, placed on an electric stove and heated to boiling at low temperature, a few drops of concentrated nitric acid are added, dissolved until smoking, and continued to heat until thick white smoke rises, removed, cooled, and the bottle wall is washed with water, 15mL hydrochloric acid is added (1+1, "1+1" is a volume ratio, specifically understood as a mixture of 1 volume of concentrated hydrochloric acid and 1 volume of water), and immediately Add stannous chloride solution (60g / L) to reduce it to light yellow, add 50mL of hot water, heat the solution to a slight boil for 1-2min, remove it, cool it to about 50℃, add 15-20 drops of sodium tungstate solution (250g / L), add titanium trichloride solution (10g / L) until blue appears, add potassium dichromate standard solution c2 (0.004166mol / L) until the blue disappears, add 4-6 drops of sodium diphenylamine sulfonate solution (2g / L), and titrate with potassium dichromate standard solution c2 (0.004166mol / L) to a stable bright purple as the end point, and record the reading V1.

[0097] Step 4: Iodine-ethanol method to separate the metallic iron in sample 3 and determine the amount of iron in the precipitate

[0098] The aluminum slag ball sample 3 containing elemental iron to be tested is placed in a 300mL conical flask, 50mL of iodine-ethanol solution is added, the bottle mouth is plugged with a rubber stopper, the conical flask is placed in an oscillating agitator, and oscillated at room temperature for 50min. Filter with medium-speed filter paper, wash the conical flask 5 times with anhydrous ethanol, precipitate 5 times, and discard the filtrate. The filter paper and precipitate are placed in a platinum crucible, ashed at 550℃, burned at 800℃ for 20 minutes, and taken out to cool. Add 2g of sodium borate carbonate mixed flux (1+2, "1+2" ​​is a mass ratio, specifically understood as 1 mass part of boric acid and 2 mass parts of sodium carbonate mixed.), burn at 1000℃ for 20 minutes, take out and cool, put it in a 250mL beaker, add 50mL of hydrochloric acid (1+1, "1+1" is a volume ratio, specifically understood as 1 volume of concentrated hydrochloric acid and 1 volume of water mixed.), heat at low temperature to completely dissolve the melt, remove and cool to room temperature, and wash out the crucible. Immediately add stannous chloride solution (60g / L) to reduce it to light yellow, add 30mL of hot water, heat the solution to a slight boil for 1-2 minutes, remove it, cool it to about 50°C, add 15-20 drops of sodium tungstate solution (250g / L), add titanium trichloride solution (10g / L) until blue appears, add potassium dichromate standard solution c2 (0.004166mol / L) until the blue disappears, add 4-6 drops of sodium diphenylamine sulfonate solution (2g / L), and titrate with potassium dichromate standard solution c2 (0.004166mol / L) to a stable bright purple as the end point, and record the reading V2.

[0099] Step 5: Calculation of metallic iron in the sample.

[0100] The calculation formula of the metallic iron content in the sample is as follows:

[0101]

[0102] In formula (3): w MFe is the content of metallic iron in the sample, %; c2 is the concentration of potassium dichromate standard solution, mol / L; V1 is the volume of potassium dichromate standard solution consumed by the total iron in sample 2, mL; V2 is the volume of potassium dichromate standard solution consumed by the iron content in the precipitate of sample 3, mL; m is the sample weight, g.

[0103] Step 6: Calculation of metallic aluminum in the sample.

[0104] The calculation formula of the metallic aluminum in the sample is as follows:

[0105]

[0106] In formula (4): w MAl is the content of metallic aluminum in the sample, %; w 合 is the total amount of metallic iron and metallic aluminum expressed as metallic aluminum content, %; w MFe is the content of metallic iron in the sample, %.

[0107] Pure iron powder, pure aluminum powder and iron oxide were mixed in proportion to prepare standard samples 1 and 2, in which the metallic iron content was 10%. The two standard samples were measured using the method in this example, and the measurement results are shown in Table 1.

[0108] Table 1 Determination results of metal aluminum content in self-made standard samples

[0109]

[0110] The above test method was used to test aluminum slag ball samples 1 and 2 containing metallic iron used in a steel plant. The test results are shown in Table 2.

[0111] Table 2 Determination results of the content of metallic aluminum in aluminum slag balls containing metallic iron

[0112]

[0113] It can be seen from Table 1 that when the metal aluminum content is 45.00%, the standard sample measurement error of the method of the present invention is 1.04%, and when the metal aluminum content is 65%, it is 1.42%, and the recovery rate is above 97.7%. The gas volumetric method provided in YS / T 1179.2-2017 has a reproducibility of R=0.96% when the metal aluminum content is 32.09%. It can be seen that the accuracy of the method of the present invention in determining the metal aluminum content in aluminum slag balls containing metallic iron can meet the analysis requirements.

[0114] It can be seen from Table 2 that the precision of the method of the present invention is equivalent to the precision SD=0.29% of the gas volumetric method for determining metallic aluminum provided in YS / T 1179.2-2017 when the metallic aluminum content is 31.98%, indicating that the precision of the method of the present invention can meet the analysis requirements.

[0115] The steps adopted by the method of the present invention are all routine laboratory operations, no special experimental equipment is required, and the range of the measured metal aluminum content is higher than that of the gas volume method. The method can effectively avoid the influence of elemental iron in the aluminum slag balls, obtain the real metal aluminum content, and the detection result is highly accurate. It solves the problem that the metal aluminum content in the aluminum slag balls is difficult to detect in actual production, and has good economic benefits and application prospects.

[0116] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0117] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0118] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron, characterized in that: The method comprises: Dissolving the aluminum slag ball sample containing elemental iron to be tested in a trivalent ferrous ion solution to perform a first oxidation-reduction reaction to obtain a first ferrous ion-containing solution; The first ferrous ion-containing solution is titrated with a potassium dichromate standard solution to perform a first titration analysis to obtain a total content W1 of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested; Dissolving the aluminum slag ball sample containing elemental iron to be tested in sulfuric and phosphoric acid mixture to obtain an aluminum slag ball sample solution containing trivalent iron ions; Adding stannous halide and titanium trihalide to the aluminum slag ball sample solution containing trivalent ferrous ions to carry out a second redox reaction to obtain a second ferrous ion-containing solution; The second ferrous ion-containing solution is titrated with a potassium dichromate standard solution to perform a second titration analysis to obtain the content W2 of all iron elements in the aluminum slag ball sample containing elemental iron to be tested; The elemental iron in the aluminum slag ball sample containing elemental iron to be tested is separated by an iodine-ethanol method, and then stannous halide and titanium trihalide are added to carry out a third oxidation-reduction reaction to obtain a third ferrous ion-containing solution; The third ferrous ion-containing solution is titrated by a potassium dichromate standard solution to perform a third titration analysis to obtain a total iron ion content W3 in the aluminum slag ball sample containing elemental iron to be tested; According to W1, W2 and W3 in the aluminum slag ball sample containing elemental iron to be tested, the elemental aluminum content W4 in the aluminum slag ball sample containing elemental iron to be tested is obtained by expression (1); The expression (1): W4 = W1-(W2-W3); In the expression (1), W1 is the total content of elemental aluminum and elemental iron in the aluminum slag ball sample containing elemental iron to be tested; W2 is the content of all iron elements in the aluminum slag ball sample containing elemental iron to be tested; W3 is the content of all iron ions in the aluminum slag ball sample containing elemental iron to be tested; W4 is the content of elemental aluminum in the aluminum slag ball sample containing elemental iron to be tested.

2. The method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron according to claim 1, characterized in that: The process parameters of the first titration analysis test include: the titration reagent is a potassium dichromate standard solution titration solution, the indicator is a sodium diphenylamine sulfonate solution, and the color of the titration endpoint solution is purple.

3. The method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron according to claim 1, characterized in that: The ferric ion solution includes at least one of a ferric sulfate ion solution and a ferric nitrate ion solution.

4. The method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron according to claim 1, characterized in that: The process parameters of the second titration analysis test include: the titration reagent is a potassium dichromate standard solution titration solution, the indicator is a sodium diphenylamine sulfonate solution, and the color of the titration endpoint solution is purple.

5. The method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron according to claim 1, characterized in that: The stannous halide includes at least one of stannous chloride, stannous bromide and stannous iodide; the titanium trihalide includes at least one of titanium trichloride and titanium tribromide.

6. The method for detecting the content of elemental aluminum in aluminum slag balls containing elemental iron according to claim 1, characterized in that: The determination range of elemental aluminum in the aluminum slag ball sample containing elemental iron is 40% to 70%.

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