Method for quickly analyzing total iron in iron ore

Abstract

The invention provides a method for quickly analyzing total iron in iron ore. The method comprises steps as follows: adding a mixed acid consisting of concentrated hydrochloric acid, concentrated nitric acid and concentrated sulfuric acid to an iron ore sample to decompose the sample, adding water for boiling until no sulfuric acid smoke exists, and cooling to the room temperature; dropwise adding an ammonia water solution until ferric hydroxide precipitates, then dropwise adding an excessive nitric acid solution until all ferric hydroxide precipitates are dissolved, then diluting the solution with water, and adjusting the pH value to range from 1 to 2; adding a sulphosalicylic acid solution, performing even mixing, dropwise adding an excessive EDTA (ethylene diamine tetraacetic acid) standard solution at the room temperature until the red color disappears, and recording the dosage of the EDTA standard solution; continuously adding a xylenol orange solution to the sample solution, dropwise adding a bismuth nitrate standard solution until the solution turns orange red from yellow, and recording the dosage of the bismuth nitrate standard solution. According to the method, the content of the total iron in the iron ore is determined by back titrating the excessive EDTA standard solution in the solution with the bismuth nitrate standard solution at the normal temperature, and the obtained result has high accuracy and precision.

Description

technical field [0001] The present invention relates to a kind of rapid analysis method of total iron in iron ore, specifically, relate to a kind of application Bi(NO 3 ) 3 - EDTA back titration method for the determination of total iron in iron ore. Background technique [0002] The content of total iron in iron ore is generally more than 10%, and the standard method uses titanium trichloride to reduce potassium dichromate titration (mercury-free method). with classical SnCl 2 -HgCl 2 -K 2 Cr 2 o 7 Compared with the mercury method (mercury method), although the highly toxic reagent mercuric chloride is replaced by titanium trichloride, the use of potassium dichromate will still damage human health and seriously pollute the environment. Therefore, the mercury-free and chromium-free method has become the main trend for the determination of iron in iron ore. At present, the EDTA complexometric titration method is mostly used. compound (lgK FeY -=25.1), using sulfosali...

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Problems solved by technology

However, the temperature of the test solution during titration by this method needs to be controlled at 50-70°C. When the temperature is higher than 75°C, the aluminum (III) ions in the test solution will complex with EDTA, so that the use of potassium acid will still damage human health and cause serious harm. seriously pollute the environment

Therefore, the mercury-free and chromium-free method has become a medium test for iron ore, and the measurement results are too high. When the temperature is lower than 50 ° C, the coordination reaction speed is slow, and the measurement results will still be high; in addition, due to a large amount of dark yellow Fe-EDTA The complex hinders the observation of the end point from purple red to bright yellow. This method is only suitable for the determination of 1-20mg iron

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