Method for rapidly analyzing calcium and magnesium in iron ore

Abstract

The invention discloses a method for rapidly analyzing calcium and magnesium in iron ore. The method comprises the following steps: (1) weighing an iron ore sample, wetting with water, adding concentrated hydrochloric acid, concentrated nitric acid, hydrofluoric acid and concentrated sulfuric acid, heating for decomposing the sample, heating for evaporating till white smoke nearly disappears, cooling, adding hydrochloric acid, heating till a solid is completely dissolved, taking down, cooling, transferring to a volumetric flask, and supplementing to a constant volume with water; (2) moving a solution with the constant volume to a glass beaker, diluting to a certain volume with water, adding sodium potassium tartrate, L-cysteine, a potassium hydroxide solution and a mixture of a calcium reagent and potassium sulfate, titrating with an EDTA standard solution to an end point, and calculating the content of the obtained calcium; (3) moving the solution with the constant volume to the glass beaker, diluting with water, adding the sodium potassium tartrate, the L-cysteine, an ammonia water-ammonium chloride buffer solution and neolan blue K-naphthol green B, and titrating with the EDTA standard solution to an end point; (4) calculating the content of the obtained magnesium by a subtraction method. The method is simple, convenient, fast and easy to master, and has relatively good practicality.

Description

technical field [0001] The invention relates to a rapid analysis method for calcium and magnesium in iron ore. Background technique [0002] Iron ore contains iron, aluminum, calcium, magnesium and other elements. The content of calcium and magnesium is generally determined by atomic absorption spectrometry or hexamethylenetetramine-copper reagent precipitation separation method. For samples with high aluminum content, the atomic absorption spectrometry will affect the spray volume, making the measurement results low; the hexamethylenetetramine-copper reagent precipitation separation method needs to adjust the sample solution with sodium hydroxide until iron hydroxide precipitation occurs , add hydrochloric acid dropwise until the precipitate just dissolves, at this time the pH of the solution is 1-2, add buffer solution hexamethylenetetramine until ferric hydroxide precipitates again, and then excess 10mL, at this time the pH of the solution is 6- 9 When the ferric hydroxi...

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Problems solved by technology

For samples with high aluminum content, the atomic absorption spectrometry will affect the spray volume, making the measurement results low; the hexamethylenetetramine-copper reagent precipitation separation method needs to adjust the sample solution with sodium hydroxide until iron hydroxide precipitation occurs , add hydrochloric acid dropwise until the precipitate just dissolves, at this time the pH of the solution is 1-2, add buffer solution hexamethylenetetramine until ferric hydroxide precipitates again, and then excess 10mL, at this time the pH of the solution is 6- 9 When the ferric hydroxide is completely precipitated, heat it on an electric furnace to 70-80°C and keep it for 10-15 minutes, then add copper reagent and aluminum, copper and other elements to form precipitates, calcium and magnesium remain in the solution, dry filter, Take the sample solution and use EDTA titration method to determine the content of calcium and magnesium

In order to control the volume of the solution when the pH value of the solution is adjusted to 6-9 on the one hand, various reagents need to be used, and the steps are complicated; on the other hand, more precipitates are produced after adding the copper reagent, which affects the constant volume of the solution. , which affects the accuracy of the results, especially for iron ore samples with high aluminum and iron content, the error is large

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