Cadmium column reduction device

Reagents and materials

1 zinc sheet.

2. Cadmium sulfate (CdSO4 · 8H2O).

Copper sulfate (CuSO4 · 5H2O).

Reagent preparation

1. Copper sulfate solution (20g/L): Weigh 20g of copper sulfate and dilute with water to 1000mL.

2. Cadmium sulfate solution (40g/L): Weigh 40g of cadmium sulfate and dilute with water to 1000mL.

Preparation of Sponge like Cadmium(Cadmium particle diameter 0.3mm~0.8mm)

Place an appropriate amount of zinc sheet into a beaker and immerse the zinc sheet in cadmium sulfate solution (40g/L). Within 24 hours, gently scrape off the sponge like cadmium on the zinc sheet continuously. Remove the residual zinc sheet, let the cadmium sink to the bottom, and pour out the upper solution. After rinsing the sponge like cadmium with water 2-3 times, transfer the cadmium to a stirrer and add 400mL of hydrochloric acid solution (0.1mol/L). Stir for a few seconds to obtain the desired particle size of cadmium particles. Pour the sponge like cadmium particles back into the beaker and let it stand for 3-4 hours, stirring several times during this time to remove any bubbles. Pour out the solution from the cadmium particles and perform copper plating on the cadmium particles using the following method.

Cadmium particle copper plating

Place the prepared cadmium particles in a conical flask (the amount of cadmium particles used should meet the required height of the cadmium column), add sufficient hydrochloric acid solution (2mol/L) to immerse the cadmium particles, shake for 5 minutes, let it stand and separate layers, pour off the upper layer of solution, and rinse the cadmium particles with water multiple times. Add copper sulfate solution (20g/L) to the cadmium particles (approximately 2.5 mL per gram of cadmium particles), shake for 1 minute, let stand and separate layers, pour out the upper layer of solution, and immediately rinse the copper plated cadmium particles with water (note that the cadmium particles should always be submerged in water) until there is no more copper precipitation in the rinsing water.

Loading of cadmium column

Fill the cadmium column glass tube with water as shown in the picture, and place about 2cm high glass wool as a pad. When pressing the glass wool towards the bottom of the column, all the air contained in it should be discharged. Under gentle tapping, add sponge like cadmium to 8cm~10cm [see Figure B.1a)] or 15cm~20cm [see Figure B.1b)], and cover it with 1cm high glass wool. If device b is used, a storage funnel should be placed on top, and the end should be tightly connected to the cadmium column glass tube through a rubber stopper. If there is no cadmium column glass tube mentioned above, a 25 mL acid burette can be used as a substitute, but attention should be paid to always keeping the liquid level above the cadmium layer when passing through the column. After the cadmium column is filled, wash it with 25mL hydrochloric acid solution (0.1mol/L) first, and then wash it twice with 25mL of water each time. When the cadmium column is not in use, cover it with water and keep the horizontal plane above the cadmium layer at all times. Do not let the cadmium layer contain bubbles.