Instruments and reagents required for soluble silicon detection
(1) Colorimetric tube, complete set of ground plug 25mL(2) Platinum crucible
(3) The solution is clear and transparent after preparation of 5% ammonium molybdate solution.
(4) 1% stannous chloride solution Weigh 1.19g stannous chloride (snCl2·2H2O) in a beaker, add 20mL hydrochloric acid solution (1+1), after heating to dissolve, add 80mL glycerol, stir well Then transfer the solution to a plastic bottle for later use.
(5) 5mol/L sulfuric acid solution was slowly added 280mL concentrated sulfuric acid to 720mL secondary reagent water.
(6) n-butanol (or isoamyl alcohol).
(7) Silica standard solution
(8) Accurately weigh 0.2500g of silicon dioxide that has been burned and ground at 700~800℃ and 4g of powdered anhydrous sodium carbonate that has been burned at 270~300℃, mix them in a platinum crucible, and add on top A layer of sodium carbonate is put into a high temperature furnace in a cold furnace and heated to 950~1000℃ to melt for h. After cooling, put the platinum crucible into a plastic beaker, dissolve the melt with hot secondary reagent water, take out the crucible after the melt is completely dissolved, and carefully rinse the outer and inner walls of the crucible with hot secondary reagent water, and wait for the solution to cool After reaching room temperature, transfer it to a 250mL volumetric flask, dilute to the mark with secondary reagent water, mix well and transfer it to a plastic bottle for storage.
(9) Accurately draw 10.0 mL of silica stock solution, accurately dilute to 500 mL with secondary reagent water, mix well and store it in a plastic bottle.
(10) Accurately absorb the 1.0m silica stock solution, accurately dilute it to 1L with secondary reagent water, mix it and store it in a plastic bottle.
Detection steps
(1) The soluble silicon content in the water sample is less than 0.5mg/L
Use a set of colorimetric tubes to respectively inject the silicon oxide working solution and dilute to 10 mL with secondary reagent water. Then take 10mL water sample and inject it into another colorimetric tube, add 0.2mL 5mol/L sulfuric acid solution and 1mL ammonium molybdate solution to the above-mentioned colorimetric tube and shake well. After standing for 5min, add 5mL5mol/L sulfuric acid solution and shake well. After standing for 1 min, add 2 drops of stannous chloride solution and shake well. After standing for 5 minutes, accurately add 3mL of n-butanol, shake vigorously 20-25 times longitudinally, and let it stand for colorimetric comparison after the solution is stratified.
(2) The soluble silicon content in the water sample is greater than 0.5mg/L (SiO2)
Use a set of colorimetric tubes to respectively inject silica working solution and dilute to 10 mL with secondary reagent water. Inject an appropriate amount of water sample into another colorimetric tube and make up to 10 mL with secondary reagent water. Add 0.2mL 5mol/L sulfuric acid solution to each of the above colorimetric tubes, and shake well. Add 1mL of ammonium molybdate solution and shake well. After standing for 5min, add 5mL5molL sulfuric acid solution, shake well, and stand for 1min. Then add 2 drops of stannous chloride solution, shake well, and let it stand for 5 minutes for color comparison.Finally, the content of soluble silicon in the water is obtained by using the relevant formula according to the detected parameters.
