Heavy Liquids Separation Heavy Liquids Overview Methylene iodide

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Heavy Liquids Separation

Heavy Liquids Separation

Heavy Liquids Overview • Methylene iodide (MI; ρ = 3. 32 g/cm 3) is

Heavy Liquids Overview • Methylene iodide (MI; ρ = 3. 32 g/cm 3) is used to concentrate material according to density. • When added to MI, materials with greater density will sink while others will float • The density of MI can be adjusted through dilution to target specific material *MI is poisonous. Contact with skin and inhalation of vapors must be avoided. *

Heavy liquids Safety and chemical handling • Under no circumstance should MI be heated

Heavy liquids Safety and chemical handling • Under no circumstance should MI be heated as it will produce poisonous gas • Proper PPE including gloves and a lab coat must be worn during MI use • MI should be stored and used in the fume hood at all times. • Samples must be rinsed completely of MI using acetone prior to drying • Do not add water to MI • All gloves and wipes used during the MI separation must be evaporated in the hood overnight before being discarded

Heavy Liquids Set up – Before starting, ensure all glassware is clean. Wipe out

Heavy Liquids Set up – Before starting, ensure all glassware is clean. Wipe out all beakers to be used with acetone. – Clean stopper and fitting with acetone – Three 500 ml beakers are used during the separation: 1. The working MI solution 2. MI + Acetone rinsed from filters and cleaning between samples 3. Acetone + small amount of MI from cleaning samples before drying

Heavy Liquids Set up – The density of MI is adjusted by diluting with

Heavy Liquids Set up – The density of MI is adjusted by diluting with acetone then measured using the hygrometer – The ratio of MI to acetone required can be calculated as followed: f. MI = (ρn + ρA)/(ρMI – ρA) ρn: Needed density ρA: Acetone density, 0. 79 g/cm 3 ρMI: MI density, 3. 32 g/cm 3

Heavy Liquids Sample separation, adding sample: • Add sample to the top of the

Heavy Liquids Sample separation, adding sample: • Add sample to the top of the column, do not overload. • Gently stir to break surface tension and rinse material stuck to sides down with acetone. • Let stand for at least 5 min, fine material may require up to 30 min.

Heavy Liquids Sample separation, removing sample: • After sample has settled, set a filter

Heavy Liquids Sample separation, removing sample: • After sample has settled, set a filter under the column, P 8 for >125 um, P 4 for <125 um • Rotate the stopper to drain the bottom of the column, close once the settled material has been removed from the column *Open slowly to avoid splashing* • After MI has drained, rinse filter and sample thoroughly in acetone and transfer sample to a 250 ml beaker. • Repeat for the floating material.

Heavy liquids Sample cleaning • Rinse and decant acetone from the sample 2 -3

Heavy liquids Sample cleaning • Rinse and decant acetone from the sample 2 -3 times. • Ultrasonically clean the sample in acetone for 5 min. • Fill the sonicator bath with water to the third set of holes to avoid damaging the motor. • Ensure sample beakers are not floating in the bath as they will tip and the contents will be lost. • Rinse and decant with acetone 2 -3 additional times. • Repeat the process a total of 2 -3 times, or more for finer material • Once all MI is removed, dry the sample under the heat lamp

Heavy Liquids Clean up • MI must be recovered for reuse as much as

Heavy Liquids Clean up • MI must be recovered for reuse as much as possible • Leave beakers with working MI and acetone rinses in the hood. Over time, acetone will separate to the top and evaporate leaving pure MI behind. • Before returning it to the bottle, ensure the MI has a density >3 g/cm 3 and pass it through a P 2 filter