CN102507853B - Method for determining metal aluminum content in steelmaking exothermal agent - Google Patents

Abstract

The invention discloses a method for determining the metal aluminum content in an exothermal agent. The method comprises the following steps of: dipping the exothermal agent by using a sodium hydroxide solution so as to dissolve metal aluminum in the exothermal agent for obtaining a metaaluminate solution; filtering the metaaluminate solution to obtain filtrate; accurately transferring partial filtrate, adding an excessive disodium ethylene diamine tetraacetic acid solution, adjusting the pH value of the solution to be 0.5-2, heating for boiling, adjusting the pH value of the solution to be 5.5-6, and heating for boiling so as to fully complex the excessive disodium ethylene diamine tetraacetic acid solution with aluminum ions; and back-dropping a zinc standard solution to the residual disodium ethylene diamine tetraacetic acid to obtain the metal aluminum content in the exothermal agent. According to the method for determining the metal aluminum content, disclosed by the invention, the metal aluminum content in the exothermal agent can be accurately detected without interferences from other chemical constituents in the exothermal agent.

Description

Method for determining metal aluminum content in steelmaking exothermal agent

Technical field

The present invention relates to make steel raw and auxiliary material chemical analysis technology field, specifically, the present invention relates to make steel the assay method of metallic aluminium content in exothermic mixture.

Background technology

In the serial exothermic mixture using in steelmaking process, contain metallic aluminium, the height of metallic aluminium content will affect the heating effect of exothermic mixture, to steel-making lumber recovery important.

Preparation exothermic mixture material used can be divided into incendiary agent (aluminium powder, silicon calcium powder, ferrosilicon powder, carbon dust, wood sawdust etc.), oxygenant (nitre, Iron Ore Powder, manganese ore powder, iron scale etc.) and adjuvant (firebrick powder, calcined bauxite in powder, ground-slag etc.), in silicon calcium powder and ferrosilicon powder, contain respectively the metallic aluminium of 2% left and right, and silicon calcium powder is the same with metallic aluminium with the silicon in ferrosilicon powder, is all reducing substances; In the materials such as carbon dust, Iron Ore Powder, manganese ore powder, firebrick powder, ground-slag, contain respectively aluminium oxide, calcined bauxite in powder is all almost aluminium oxide.Therefore, while measuring the metallic aluminium content in exothermic mixture, silicon in aluminium oxide in exothermic mixture and silicon calcium powder and ferrosilicon powder, metallic iron, calcium metal all may produce severe jamming, thereby cause being difficult to find a kind of analytical approach that can detect more exactly metallic aluminium content in steel-making exothermic mixture.

Summary of the invention

For the problems referred to above of the prior art, the invention provides a kind of method of measuring the metallic aluminium content in exothermic mixture, said method comprising the steps of: with sodium hydroxide solution, leach exothermic mixture, to dissolve the metallic aluminium in exothermic mixture, obtain meta-aluminate solution; Filter meta-aluminate solution, obtain filtrate; Accurately pipette part filtrate, add excessive disodium ethylene diamine tetra-acetic acid solution, regulator solution pH is 0.5～2, and heating is boiled, then regulator solution pH is 5.5～6, and heating is boiled, and makes the abundant complexing of excessive disodium ethylene diamine tetra-acetic acid solution and aluminium ion; With the remaining disodium ethylene diamine tetraacetate of zinc titer residual titration, thereby obtain the metallic aluminium content in exothermic mixture.

Preferably, for 1g exothermic mixture, when the mass percentage content of metallic aluminium is lower than 30% time, add the disodium ethylene diamine tetra-acetic acid solution of 1.2mmol～1.5mmol.For 1g exothermic mixture, when the mass percentage content of metallic aluminium is higher than 30% time, add the disodium ethylene diamine tetra-acetic acid solution of 2.4～3.0mmol.

Preferably, in the process with sodium hydroxide solution leaching exothermic mixture, solution is heated to boiling.

According to the present invention, be calculated as follows metallic aluminium content:

$w\left(\mathrm{Al}\right)=\frac{(C_1{\×V}_1-C_2{\×V}_2)\×26.98154}{m\÷10\×{10}^3}\×100$

Wherein, the mass percent that w (Al) is metallic aluminium; V ₁for the volume of the disodium ethylene diamine tetra-acetic acid solution that adds, unit is mL; V ₂for adding the volume of zinc titer, unit is mL; C ₁for the concentration of disodium ethylene diamine tetra-acetic acid solution, unit is mol/L; C ₂for the concentration of zinc titer, unit is mol/L; M is the quality that takes test portion, and unit is g.

According to the method for mensuration metallic aluminium content of the present invention, can detect exactly the metallic aluminium content in exothermic mixture, and not be subject to the interference of other chemical composition in exothermic mixture.

Embodiment

By research concentration be 1.2mol/L～5mol/L sodium hydroxide solution respectively with exothermic mixture, silicon calcium powder, ferrosilicon powder, carbon dust, Iron Ore Powder, firebrick powder, calcined bauxite in powder, the response situation of ground-slag etc., the sodium hydroxide solution cumulative volume that dissolved samples is controlled in discovery under heating state is 150 milliliters, when sodium hydroxide solution (200g/L) addition is 20～80 milliliters, the sodium hydroxide solution of variable concentrations can make the metallic aluminium powder adding in exothermic mixture dissolve completely, magnesia, aluminium oxide in magnesia-alumina brick is insoluble to sodium hydroxide solution, sodium hydroxide solution can only dissolve electroslag, high-alumina brick powder, the aluminium oxide of seldom measuring in coke blacking sample, in the samples such as sodium hydroxide solution dissolved iron breeze, clay, bauxite powder, the amount of aluminium oxide increases with the increase of concentration of sodium hydroxide solution, when controlling the sodium hydroxide solution cumulative volume of dissolved samples, it is 150 milliliters, and when sodium hydroxide solution (200g/L) addition is 50 milliliters, the aluminium oxide that Iron Ore Powder, clay, bauxite powder dissolve is separately about 2%.Sodium hydroxide solution can only dissolves silicon iron powder in the aluminium of minute quantity.Therefore, during with sodium hydroxide solution leaching exothermic mixture, can only dissolve the metallic aluminium of minute quantity in metallic aluminium powder, ferrosilicon powder and the silicon calcium powder adding in exothermic mixture and dissolve a small amount of aluminium oxide in ground-slag, magnesia-alumina brick powder, high-alumina brick powder, coke blacking, Iron Ore Powder, bauxite powder.Metallic aluminium content approximately 2% left and right in ferrosilicon powder, silicon calcium powder, and ferrosilicon powder, the total amount of silicon calcium powder in aluminium heat pyrexia agent are no more than 50%; The aluminium oxide total amount of dissolving in ground-slag, magnesia-alumina brick powder, high-alumina brick powder, coke blacking, Iron Ore Powder, bauxite powder is no more than 2%, so, with in sodium hydroxide solution leaching-disodium ethylene diamine tetraacetate volumetric determination exothermic mixture during metallic aluminium content, its error is no more than 1%, can meet well STEELMAKING PRODUCTION demand.

To describe in detail according to the method for metallic aluminium content in employing NaOH leaching-disodium ethylene diamine tetraacetate volumetric determination exothermic mixture of the present invention below.

According to metallic aluminium content in NaOH-disodium ethylene diamine tetraacetate volumetric determination exothermic mixture of the present invention, be applicable to the situation that metallic aluminium content in exothermic mixture is greater than 1.0% (mass percent).

According to the method for mensuration metallic aluminium content of the present invention, metallic aluminium is dissolved as meta-aluminate in sodium hydroxide solution, filtering solution with other separating substances.Add disodium ethylene diamine tetra-acetic acid solution, pH value is adjusted to 0.5～2, heating is boiled; PH is adjusted to approximately 5.5～6.0, heating is boiled, and is cooled to room temperature, take xylenol orange as indicator, with the excessive disodium ethylene diamine tetra-acetic acid solution of zinc titer residual titration again.

According to the method for mensuration metallic aluminium content of the present invention, the chemical reagent adopting can be as follows: hydrochloric acid (1+1), sodium hydroxide solution (200g/L), methyl orange solution (1.00g/L), disodium ethylene diamine tetraacetate standard solution (0.02000～0.2000mol/L), hexamethylenetetramine solution (420g/L), xylenol orange solution (2.00g/L), zinc titer (0.01000～0.03000mol/L, about 0.08mol/L hydrochloric acid medium).

To describe in detail according to the method for metallic aluminium content in NaOH-disodium ethylene diamine tetraacetate volumetric determination exothermic mixture of the present invention below.

First, take sample to be tested 1.0g and be placed in beaker, add 100mL～150mL water, and add 20mL～50mL sodium hydroxide solution (200g/L), beaker is placed on low temp. electric stone or metal plate for standing a stove on as a precaution against fire and is heated to boiling, stop heating after 5～6 minutes, mix; Again be heated to boiling, stop heating after 5～6 minutes, mix; Above-mentioned heating process repeatedly, until in solution, do not have minute bubbles to produce, then beaker is placed after 40 minutes on hot electric furnace pan, being cooled to normal temperature, water is accurately diluted to 500mL, mixes.

In said process, as previously mentioned, sodium hydroxide solution can dissolve the metallic aluminium in exothermic mixture completely, and generates meta-aluminate; And for the aluminium oxide in exothermic mixture, NaOH can only dissolve very small amount of aluminium oxide, and a small amount of aluminium oxide dissolving is very little to the determination influences of metallic aluminium content.

Then, with double-deck slow curing Filter Paper Dry, filter, filter initial solution, get 50.00mL filtrate in triangular flask, the disodium ethylene diamine tetraacetate that adds 0.02000～0.2000mol/L is 1.2～1.5mmol approximately, mixes.Now, if metallic aluminium content is greater than 30% in exothermic mixture, the disodium ethylene diamine tetraacetate that adds 0.02000～0.2000mol/L is 2.4～3.0mmol approximately.In solution, add 2-3 to drip methyl orange solution (1.00g/L), mix, with hydrochloric acid (1+1), be titrated to solution and be stable redness, excessive 1.00mL, mixes, and 1-2 minute is boiled in heating, slightly cold, add 10.0mL hexamethylenetetramine solution (420g/L), mix; On middle low temp. electric stone or metal plate for standing a stove on as a precaution against fire, heat and boil approximately 10 minutes, in cooling bath, be chilled to room temperature, add 50mL water, mix; Add 0.4mL xylenol orange solution (2.00g/L), mix, with zinc titer (0.01000～0.03000mol/L, about 0.08mol/L hydrochloric acid medium), being titrated to solution, to be stable redness be terminal.

In said process, adopt remaining disodium ethylene diamine tetra-acetic acid solution in zinc titer titration trivalent aluminium and disodium ethylene diamine tetraacetate course of reaction, thereby measure the content of metallic aluminium in exothermic mixture.

Be calculated as follows metallic aluminium content:

$w\left(\mathrm{Al}\right)=\frac{(C_1{\×V}_1-C_2{\×V}_2)\×26.98154}{m\÷10\×{10}^3}\×100$

In formula: V ₁-add the volume of disodium ethylene diamine tetra-acetic acid solution, mL;

V ₂-add the volume of zinc titer, mL;

C ₁the concentration of-disodium ethylene diamine tetra-acetic acid solution, mol/L;

C ₂the concentration of-zinc titer, mol/L;

M-takes test portion quality, g.

The method of mensuration metallic aluminium content of the present invention is described below with reference to concrete example.

According to table 1 below, take the samples such as metallic aluminium powder, ferrosilicon powder, silicon calcium powder, carbon dust, electroslag, magnesite-chrome brick, magnesia-alumina brick, high-alumina brick, clay, Iron Ore Powder, calcined bauxite in powder in 600 milliliters of wide-mouth King beakers, synthetic 16 kinds are mixed exothermic mixture sample, press the operation of sodium hydroxide solution leaching-disodium ethylene diamine tetraacetate volumetric method, testing result is in Table 1.

Table 1 adopts sodium hydroxide solution leaching-disodium ethylene diamine tetraacetate volumetric method to measure the result of metallic aluminium content

By table 1, can find out, except adding the recovery that adds metallic aluminium powder of the mixing exothermic mixture sample of 414 clay 0.4081g, be 105.34%, all the other recovery that add metallic aluminium powder of respectively mixing exothermic mixture sample are all 98%～102%, in general aluminium heat pyrexia agent, metallic aluminium content is 20% left and right, therefore, with in sodium hydroxide solution leaching-disodium ethylene diamine tetraacetate volumetric determination aluminium heat pyrexia agent during metallic aluminium content, absolute error is generally not more than 0.5%, the most about 1%.Explanation thus, sodium hydroxide solution leaching-disodium ethylene diamine tetraacetate volumetric method can be checked metallic aluminium content in aluminium heat pyrexia agent exactly.

In addition, by sodium hydroxide solution leaching-disodium ethylene diamine tetraacetate volumetric method, CY-4 exothermic mixture sample, RS-3 exothermic mixture sample are detected, testing result is in Table 2.

The testing result of table 2 sodium hydroxide solution leaching-disodium ethylene diamine tetraacetate volumetric method test samples

The data of table 2 show, in CY-4 exothermic mixture, metallic aluminium content is more even, and in RS-3 exothermic mixture, metallic aluminium content is inhomogeneous, but 5～6 parts of samples of Parallel testing, its mean value coincide fine.Explanation thus, although metallic aluminium skewness in steel-making exothermic mixture, the mean value that Parallel testing is 5～6 times can represent the real content of metallic aluminium in sample.

According to the method for mensuration metallic aluminium content of the present invention, can detect exactly the metallic aluminium content in exothermic mixture, and not be subject to the interference of other chemical composition in exothermic mixture.

Claims (5)

1. a method of measuring the metallic aluminium content in exothermic mixture, is characterized in that said method comprising the steps of:

With sodium hydroxide solution, leach exothermic mixture, to dissolve the metallic aluminium in exothermic mixture, obtain meta-aluminate solution;

Filter meta-aluminate solution, obtain filtrate;

Accurately pipette part filtrate, add excessive disodium ethylene diamine tetra-acetic acid solution, regulator solution pH is 0.5～2, and heating is boiled, then regulator solution pH is 5.5～6, and heating is boiled, and makes the abundant complexing of excessive disodium ethylene diamine tetra-acetic acid solution and aluminium ion;

With the remaining disodium ethylene diamine tetraacetate of zinc titer residual titration, thereby obtain the metallic aluminium content in exothermic mixture.

2. method according to claim 1, is characterized in that, for 1g exothermic mixture, when the mass percentage content of metallic aluminium is lower than 30% time, adds the disodium ethylene diamine tetra-acetic acid solution of 1.2mmol～1.5mmol.

3. method according to claim 1, is characterized in that, for 1g exothermic mixture, when the mass percentage content of metallic aluminium is higher than 30% time, adds the disodium ethylene diamine tetra-acetic acid solution of 2.4～3.0mmol.

4. method according to claim 1, is characterized in that, in the process with sodium hydroxide solution leaching exothermic mixture, solution is heated to boiling.

5. method according to claim 1, is characterized in that being calculated as follows metallic aluminium content:

$w\left(\mathrm{Al}\right)=\frac{(C_1{\×C}_1-C_2{\×V}_2)\×26.98154}{m\÷10\×{10}^3}\×100$

Wherein, the mass percent that w (Al) is metallic aluminium; V ₁for the volume of the disodium ethylene diamine tetra-acetic acid solution that adds, unit is mL; V ₂for adding the volume of zinc titer, unit is mL; C ₁for the concentration of disodium ethylene diamine tetra-acetic acid solution, unit is mol/L; C ₂for the concentration of zinc titer, unit is mol/L; M is the quality that takes test portion, and unit is g.