Shandong Langrun Blue Valley Industrial Park explains how to extract elemental iodine kelp

1. Clean kelp with a brush (do wash with water). 40g of kelp du was weighed, cut into strips sheets (as small as possible) with scissors, placed in a crucible, added 30 mlnaoh solution, covered, heated in an electric furnace for 1 hour, then transferred to maafu furnace, heated at 600℃ for 2 hours 30 minutes, to make kelp completely ash. (Pay attention to ventilation during heating)

2. After the kelp ash is cooled, pour it into the mortar fully grind it, then transfer it to a 250mL beaker, add 40mL, 20mL 10mL distilled water boil it successively, after each boil, extract retain the filtrate. The filtrate extracted three times should be combined together the total volume should exceed 30mL.

3. Add H2SO4 solution to filtrate for acidification adjust the pH value to be neutral. Pour the acidified filtrate into the evaporating dish, evaporate to dry fry as much as possible, transfer the solids to the mortar, add 2g of potassium dichromate solid, grind fine.

4. Put the above mixture into a tall, dry beaker. Put the flask with ice water cooled in it on the mouth of the beaker. The iodine vapor condenses at the bottom of the flask. When no purple iodine vapor is produced, stop heating. Remove the flask, scrape the condensed solid iodine the flask into a small weighing flask weigh it. The percentage of iodine in kelp was calculated.

1. Take 10g of dried kelp brush the surface attachments with a brush. Do wash them with water. Cut the kelp into pieces, moisten it with alcohol put it into a porcelain crucible. Place the crucible on the clay triangle.

2. Burn the crucible containing kelp with alcohol lamp until the kelp is completely burnt into charcoal black gray, then stop heating cool naturally.

3. Put the kelp ash in the crucible into a small beaker, add 15mL distilled water, stir continuously, boil for 4min ~ 5min, dissolve the soluble substance, filter after 10 minutes.

4. Divide the filtrate into four parts put them in the test tube. Label the filtrate as 1, 2, 3 4. After 6 drops of dilute sulfuric acid were added into the no.1 test tube, the solution of about 3mLH2O2 was added to observe the phenomenon. Add 1% starch solution 1-2 drops, observe the phenomenon.

5. Add 2mL newly made saturated chlorine water into test tube No. 2 oscillate the solution to observe the phenomenon. Divide the solution with chlorine water into two parts after 2 minutes. Add another 1% starch solution 1-2 drops in a, observe the phenomenon. 2mLCCl4 was added to B solution extracted by oscillation. After standing for 2 minutes, the phenomenon was observed.

6. Add 10mL NaOH solution to the test tube with CCl4 solution, fully oscillate, pour the mixed solution into the specified container. Sodium hydroxide is added to absorb iodine dissolved in CCl4, the remaining solution is poured into the designator to prevent environmental pollution.

7. Add 3g iodized salt into tube 3, shake to make it fully dissolved, then add 6 drops of dilute sulfuric acid. Add 1% starch solution 1-2 drops, observe the phenomenon.

8. Add silver nitrate solution to test tube no. 4, shake, add dilute nitric acid solution. Observe the experimental phenomena.

9. Repeat the above experiment with kelp products three different origins.