Determination of chromium in high carbon ferrochrome powder

High carbon ferrochrome is mainly used in stainless steel production, improve the hardenability of steel, increase the wear resistance and hardness of steel; Used as an additive to cast iron to improve the wear resistance and hardness of cast iron. As one of the main products of our company, our company will give you a brief introduction of the method of determining the chromium element in high carbon ferrochrome based on the understanding of high carbon ferrochrome over the years.

First, 0.1000g sample was weighed in a nickel crucible, 2g potassium hydroxide was added, and 0.5 g potassium nitrate was covered in a Muffle furnace at 700℃. After melting for 15 minutes, the sample was cooled and placed in a 300ml beaker. Add 50ml deionized water, cover the surface dish, after the intense reaction stops, heat and boil for 10 minutes, remove and place, wash out the crucible and cover with water, add 20ml sulfuric acid, heat until boiling, remove slightly cold, move the solution to 500ml conical bottle.

Then, add 10ml phosphoric acid, dilute with water to 250ml, shake well, add 10ml silver nitrate solution, 20ml ammonium persulfate solution, shake well, heat. The content of manganese in the sample is low, need to add a few drops of potassium permanganate solution, boil until the solution presents a stable rose red color] continue to boil for 5 minutes, remove.

After that, add 10ml sodium chloride solution and boil until the redness disappears. Continue boiling for 8-10 minutes to make the silver chloride precipitate, coagulate and sink. Remove and cool to room temperature. Titrate with ammonium ferrous sulfate standard solution until the solution is light yellow, add 3~5 drops of phenylanthranilic acid indicator, continue titrating until the rose color disappears and turns to bright green as the end point, we need to take down the volume V consumed by ammonium ferrous sulfate standard solution.