How to determine SiO2/Na2O ratio after mixing Na2SiO3 (SiO2=30%, Na2O=9%, water=61%)and NaOH (8M)solutions?
Thank you.
This mix is used in concrete technology. They mix Na2SiO3 solution and NaOH solution and add it to fly ash and aggregate to make concrete. The resulting SiO2/Na2O ratio is important for making concrete. I want to know how it is determined. I have seen somewhere they mentioned they have mixed NaOH (5 M) and Na2SiO3 (SiO2=30%, Na2O=9%, water=61%)with a Na2SiO3/NaOH ration of 1.5, and the resulting SiO2/Na2O ratio is 0.15, but they haven't mentioned how.
Sodium metasilicate mixed with cold, concentrated sodum hydroxide yields sodium orthosilicate and water
Na2SiO3 + 2NaOH → Na4SiO4(in solution) + H2O
Now, your question. looking at mass relationships..
assume one mole of each..
122grams + 80 g>>>184g+ 18
of the 184 grams of sodium orthosilicate, one can Pull from it 124 grams of Na2O, and 60g of SiO2. That on the basis of mass, is about 2:1 ratio
Honestly, the way your question is worded, I am not certain what it is aiming for.
To determine the SiO2/Na2O ratio after mixing Na2SiO3 and NaOH solutions, you need to calculate the moles of SiO2 and Na2O in the original solutions and then calculate the moles of each component in the final solution.
Here are the steps to follow:
Step 1: Calculate the moles of SiO2 and Na2O in the Na2SiO3 solution.
- Given that the concentration of Na2SiO3 is 30%, you can assume you have 30 grams of Na2SiO3 in 100 grams of solution.
- Calculate the moles of SiO2 and Na2O separately using their respective molar masses.
- The molar mass of SiO2 is 60.08 g/mol, and the molar mass of Na2O is 61.98 g/mol.
- Divide the mass of each component by its molar mass to get moles.
Step 2: Calculate the moles of NaOH in the NaOH solution.
- Given that the concentration of NaOH is 8 M, you have 8 moles of NaOH in 1 liter of solution.
Step 3: Determine the moles of each component in the final solution.
- Assume you mixed equal volumes of the Na2SiO3 and NaOH solutions.
- If you mixed 1 liter of each solution, you would have an equal number of moles of each component in the final solution.
Step 4: Calculate the SiO2/Na2O ratio in the final solution.
- Divide the moles of SiO2 in the final solution by the moles of Na2O in the final solution to get the ratio.
Following these steps will help you determine the SiO2/Na2O ratio after mixing Na2SiO3 and NaOH solutions.