[Music] hello friends in this video we will be extracting pure silicon dioxide from sand materials required for this synthesis include of course sand sodium hydroxide 50 gram 300 milliliters of distilled water 50 milliliters of 3 molar hydrochloric acid and 30 milliliters of 98% sulfuric acid so yeah basically I went to the base last day so I collected some 500 grams of sand from d'Or the sand I collected was more of course type and had a lot of organic matter like leaves so I had to first wash the sand with plain water to remove all the
organic and other suspended particles then I added 50 milliliters of 3 molar hydrochloric acid to remove all the soluble impurities mainly calcium carbonate in anticipation of too much facing and bubbling initially I added few ml of hydrochloric acid but to my surprise the sand I collected had very few carbonates so I decided to add all the acid at once you can see few bubbling here and there but as a whole it was much purer I sold the flask for 5 to 10 minutes to ensure complete reaction then I decant it off the acid and washed
the sand a couple of number of times with water to remove all the acid then I decided to dry the sand so I transferred it onto a petri plate and let it outside in the Sun to dry this is the much puris and I got after washing and drying you can see some black and brown particles here and there but more than that there are colorless crystals which are all silica particles which we will be extracting now transfer this dry sand into a stainless steel vessel and start heating had prevailed 50 grams of sodium hydroxide
into it my sodium hydroxide was a little damp and too much clumps were present so I had to break them up for even transfer of heat for this step don't use a glass vessel or a glass tea road because you know that hot molten alkali send glass not a good combination what's happening here is sodium hydroxide reacts with silicon dioxide in sand to form sodium silicate after about five minutes you can see a lot of water because my sodium hydroxide was damp after about 20 minutes of heating you can see that most of the water
has evaporated off and the reaction has finally started to sit in stir the mixture continuously throughout the heating process I am using a stainless steel spatula for steering by about 40 minutes the reaction is almost getting into completion and mixture is getting very thick now then I took it from the heat source and immediately transferred it onto a piece of wood do this step very fast or it will be very difficult later then I transferred the crude sodium silicate into a porcelain mortar and added 300 milliliters of distilled water in small additions with constant stirring
try to dissolve as much as sodium silicate you can finally we are left with a turbid yellow solution which I had to decant from the porcelain mortar which is the sodium silicate solution now in the mortar you can see some unreacted sand particles then I filtered this solution of sodium silicate using gravity filtration method and then started adding concentrated sulfuric acid drop by drop into it with steering I had to add 30 milliliters ninety-eight percentage sulfuric acid on adding the acid you can hear this characteristic sound concentrated acid alkali reaction is extremely exothermic so we
have to be very careful after sometimes silicic acid crashes out as a white precipitate you won't be seeing this precipitate immediately on adding the sulfuric acid but after some time you can see that after all the sulfuric acid is added filter the solution I am just using a two cotton cloth to filter out the silicic acid as the precipitate is extremely slimy and it will be very difficult for simple gravity filtration vacuum filtration method is best if you have one finally we get the white slimy precipitate of silicic acid the next step is to heat
the silicic acid to high temperature I am using a clay tile over an open Bunsen burner flame I place the silicic acid particles on it and heated it to very high temperatures i could virtually see the red hot tiles what's happening here is silicic acid is getting decomposed by heat to silicon dioxide i heated it for about one hour and then pulverized the mixture with the help of a pestle after that I transferred all this silicon dioxide powder into a mortar and pestle and thoroughly grinded it into fine particles after making it into a fine
powder I stored it in an airtight container and labeled it I would like to take this opportunity to thank my patreon supporters who have financially supported me so that I could get the materials required for doing all these experiments including this one thank you so much for watching my video if you allowed the contents of this video do subscribe to my channel and click on the bell button so that you will get notified about my new videos
