Determination of free sodium cyanide in leaching solution
2020-09-07 11:04Introduction：Determination of free sodium cyanide in leaching solution Silver nitrate volumetric method was used. In alkaline solution, silver cyanide complex ion was formed by titration with silver nitrate standard solution. When measuring point, exce
Determination of free sodium cyanide in leaching solution
Silver nitrate volumetric method was used. In alkaline solution, silver cyanide complex ion was formed by titration with silver nitrate standard solution. When measuring point, excess silver ion and indicator form orange red, the end point is bright.
Aalytical reagent：
（2）Silver nitrate standard solution: accurately weighing 1.734 grams of silver nitrate which has been dried at 110 ℃, dissolved in distilled water, transferred into 1000ml brown volumetric bottle, diluted to standard line, shake well. Wrap in black paper and set aside in the dark.
This solution is equivalent to 1 milligrams of sodium cyanide per milliliter.
Analytical procedures:
Accurately absorb test solution 10 ml in 100ml conical bottle, add about 0.5ml test silver indicator, when silver nitrate standard solution is titrated to the solution from bright yellow to orange-red, it is the end point.
Calculate the content of sodium cyanide by the following formula:
NaCN mg /l＝[ (1×V1)/V0]×1000
In the form of:
1——Titration of sodium cyanide for silver nitrate standard solution (1 mg / ml)；
VO——Volume (ml) of the tested solution, typically 10ml;
V1——Amount of silver nitrate standard solution consumed in titration (ml);
1000——Coefficient of conversion from milliliters to liters.
Nes appended to a book, etc：
This method can also use 5% potassium iodide as indicator, and the end point is yellow turbidity.
Chemical reaction：
AgNO3+2NaCN=NaAg(CN)2+NaNO3
AgNO3+KI=AgI↓(Yellow)+KNO3
