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Method for detecting calcium oxide content in limestone with dbc-arsenazo indicator

An arsine azo and indicator technology, which is applied in the field of chemical analysis of metallurgical auxiliary raw materials, can solve problems such as unsatisfactory repeatability of analysis results and affect the consistency of titration end point judgment, and achieve the effects of easy observation, simple operation and good reproducibility

Active Publication Date: 2015-11-04
DAYE SPECIAL STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, due to physiological reasons, some analysts are not sensitive to the color change process from red to blue, which affects the consistency of titration end point judgment, resulting in unsatisfactory repeatability of analysis results.

Method used

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  • Method for detecting calcium oxide content in limestone with dbc-arsenazo indicator
  • Method for detecting calcium oxide content in limestone with dbc-arsenazo indicator
  • Method for detecting calcium oxide content in limestone with dbc-arsenazo indicator

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Experimental program
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Effect test

Embodiment 1

[0030] The mensuration of calcium oxide content in the limestone of embodiment 1

[0031] Step 1: Weigh 0.5000g of the sample to be tested, place it in a platinum crucible filled with 3.0g of mixed flux (made by grinding and mixing 2 parts of anhydrous sodium carbonate and 1 part of boric acid), cover it, and place it at a high temperature of 980°C In the furnace, melt for 15 minutes, take out the platinum crucible, turn it while it is hot, and cool it to room temperature;

[0032] Step 2, put the cooled platinum crucible in a 300ml beaker, add 100ml of deionized water, 15ml of concentrated hydrochloric acid (hydrochloric acid with a mass fraction of 37%), heat and leach the frit in the platinum crucible at about 75°C, and leaching Finally, take out the platinum crucible, cool the leaching solution to room temperature, then dilute the leaching solution to 250ml with water, shake well, this is the stock solution (i.e. the sample solution to be tested);

[0033] Step 3, take 25...

Embodiment 2

[0046] Embodiment 2, the selection experiment of titrated acidity in the detection method of the present invention

[0047] Use a pH meter as an adjustment device to measure Ca at pH values ​​of 7.5, 8.1, 8.4, 9.2, 10.2, 10.7, 11.3, 12.4, and 13.1 2+ The absorbance of the complex formed with DBC-Arsenazo at a wavelength of 620nm can be determined from the absorbance value of Ca 2+ The complex formed with DBC-Arsenazo has stable absorbance at pH ≥ 10.

[0048] Therefore, in the present invention, the titration experiment is selected to be completed under the condition of PH≧12, at this time, a stable observed color can be obtained in the solution.

Embodiment 3

[0049] Embodiment 3, the concentration measurement experiment that allows the coexistence of interfering cations in the method of the present invention

[0050]In this embodiment, except that step 3 is different from step 3 of embodiment 1, other operating steps are the same as in embodiment 1. The sample to be tested in this embodiment is limestone standard sample GBW03107, and step 3 of this embodiment is specifically as follows: To 65 250ml Erlenmeyer flasks, add 1mL of solutions containing different metal cations (interfering cations) with different concentration gradients in advance, and then add 25ml of sample stock solution, 25ml of deionized water, and 5ml of triethanolamine solution (triethanolamine) in sequence. The mass percent concentration is 20%), 10ml potassium hydroxide solution (the mass percent concentration of potassium hydroxide is 20%), the pH of the solution is 12 at this time, and the metal cation solution of each concentration gradient is repeatedly meas...

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Abstract

The invention provides a method for detecting the content of calcium oxide in limestone by using a DBC (Dibromochloro)-arsenazo indicator. The method comprises the following steps: step 1, preparing a sample solution to be detected; step 2, taking the sample solution to be detected in the step 1 and adding triethanolamine; adjusting the pH value of an obtained solution to be more than or equal to 12 by using a strong base; step 3, adding the DBC-arsenazo indicator into the solution obtained by the step 2, wherein the DBC-arsenazo indicator is prepared by uniformly grinding DBC-arsenazo and sodium chloride; step 4, titrating the solution obtained by the step 3 by using standard EDTA (Ethylene Diamine Tetraacetic Acid) solution until the color of the solution becomes red from blue, namely reaching the final point; then calculating to obtain the content of the calcium oxide. At the titrating final point of the method, the color becomes red from blue, so as to be good for observing by an analyzer; the analysis result has good accuracy and repeatability. Furthermore, the method is simple and convenient to operate and is time-saving; conventional interference elements can coexist in high concentrations.

Description

technical field [0001] The invention belongs to the technical field of chemical analysis of metallurgical auxiliary raw materials, and in particular relates to a method for detecting calcium oxide content in limestone with a DBC arsenazo indicator. Background technique [0002] DBC-Arsenazo, the full name is 3-(2-Arsenoylphenylazo)-6-(2,6-dibromo-4-chlorophenylazo-4,5-dihydroxy-2,7-naphthalene Disulfonic acid, abbreviated as DBC-ASA, was used as a rare earth developer. [0003] Lime is the basic raw material of the iron and steel industry. As a slagging agent, it has the advantages of shortening the smelting time and improving the purity of molten steel. It is also used in the refining of molten steel and the sintering of iron ore powder. The main raw and auxiliary materials for the sintering process. [0004] There are many analysis methods for lime (stone), and the routine inspection is mostly under the condition of solution pH ≥ 12, using calcium indicator or chrome bla...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N31/16G01N21/79
Inventor 张海
Owner DAYE SPECIAL STEEL CO LTD