How to measure the calcium chloride content
Thread Content
There is a solution that contains approximately 15%–40% calcium chloride; in addition, it contains about 10%–34% hydrochloric acid, as well as trace amounts of iron, magnesium, and other elements. How to determine the content of calcium chloride in a solution (mass percentage)? Could some expert help me out? Thanks in advance!
Isn’t this knowledge from middle school? Add phosphoric acid or sulfuric acid to form a precipitate, filter it, dry it, weigh its mass, and then calculate the amount of Ca based on the molecular weight ratio
This test isn’t that difficult, is it? The precipitation method can be used, as well as the photometric method. It’s actually to measure the calcium ion concentration! ! ! There are national standards! !
You can refer to GB7477-87 \"Water quality – Determination of total calcium and magnesium – EDTA titration method\". The general steps are as follows: Take a small amount of the sample solution, dilute it, add triethanolamine or a hydride to mask iron, add chrome black T as an indicator, adjust the pH to 10, and then titrate with EDTA.
Just use the method for determining calcium ions; it’s specified in the national standards
If the iron content is low, it can be diluted and masked with triethanolamine; magnesium can be masked by adjusting the pH to above 12 with KOH before direct measurement. If accurate determination is still not possible using the methods mentioned above, iron can be masked with tartaric acid, calcium can be precipitated as calcium oxalate, and after filtering to separate the calcium oxalate, the calcium content can be determined by gravimetric or redox methods. After the calcium content is determined, it is then converted into the calcium chloride content.
A standard solution can be used along with an excess of silver nitrate; after precipitation and filtration, the silver chloride precipitate is dried to determine the total Cl- concentration. Then titrate the acid concentration using a pH indicator, and just measure the difference
The specific gravity of the solution can also be measured, after which the percentage content can be determined by referring to a table.
Adjust the pH to neutral, add triethanolamine, add NaOH until the pH reaches 12, add a calcium indicator, and then titrate with EDTA
Thank you, the person above; we used this method. This post was last edited by chenfeiyan3025 on 2008-11-22 04:24]