How to buy talc powder

1. Source of medicinal materials: Talc is a silicate mineral talc group of talc, mainly containing hydrous magnesium silicate. It has the effect of diuretic and stranguria, clearing away heat and relieving summer heat.

2. Processed medicinal materials: talcum powder, which is made by selection, purification, crushing and drying.

Tips for buying talcum powder

1. Look at the appearance

Talc is a massive aggregate. Irregular lumps. White, yellowish-white or light blue-gray with waxy luster. Soft, delicate, smooth to the touch, non-hygroscopic, not disintegrating in water.

Talc is a white or off-white, fine, non-sand-like powder with a greasy feel to the touch.

2. Taste

Gas micro, tasteless.

Talcum Powder Buying Tips

1. It is better to be clean, bluish white, smooth and free of impurities.

2. Choose a merchant with complete qualifications, and products with complete product information such as the trademark, manufacturer's address, approval number, and date of manufacture are printed on the package.

Mistakes in buying talcum powder

Is talcum powder harmful to the human body?

The main component of talc is magnesium hydrosilicate. No obvious harm to human body.

Buying Pitfalls of Talc

1. Talc counterfeit: anhydrite;

Anhydrite: It is processed from the orthorhombic mineral anhydrite. It is a white fine powder, slightly glossy, smooth to the touch, sticky to the tongue, and melts in contact with water. Slight smell.

The purchase process of talcum powder

Select the desired product → choose a regular merchant to buy.

Standard for talcum powder

This product is a silicate mineral talc talc, mainly containing hydrous magnesium silicate.

【Identification】

(1) Take 0.2g of the powder of this product, put it in a platinum crucible, add the same amount of calcium fluoride or sodium fluoride powder, stir, add 5ml of sulfuric acid, heat slightly, immediately cover the platinum crucible with 1 drop of water, and put it on the platinum crucible for a while. After a while, remove the platinum crucible cover, the water droplets appear cloudy white.

(2) Take 0.5g of this product powder, put it in a beaker, add 10ml of hydrochloric acid solution (4→10), cover it with a watch glass, heat it to a slight boil, shake the beaker from time to time, and keep it at a slight boil for 40 minutes, remove it, use Filter through fast filter paper, and wash the residue with water 4 to 5 times. Take about 0.1 g of the residue, put it in a platinum crucible, add 10 drops of sulfuric acid (1→2) and 5 ml of hydrofluoric acid, heat it until white smoke of sulfur trioxide is emitted, remove it and cool it, add 10 ml of water to dissolve, and take 2 drops of the solution . Add 1 drop of magnesium reagent (dissolve 0.01 g of p-nitroazoresorcinol in 1000 ml of 4% sodium hydroxide solution), add dropwise sodium hydroxide solution (4→10) to make it alkaline, and form a sky blue precipitate .

【an examination】

PH: Take 10g of this product, add 50ml of water, boil for 30 minutes, replenish the evaporated water from time to time, and filter. The filtrate should show a neutral reaction when it encounters neutral litmus paper.

Soluble in water: take 5g of this product, accurately weigh it, put it in a 100ml beaker, add 30ml of water, boil for 30 minutes, replenish the evaporated water from time to time, let it cool, filter it with slow filter paper, add 5ml of water to the filter residue to wash, and the washing solution Combined with the filtrate, evaporated to dryness, dried at 105 ° C for 1 hour, the remaining residue should not exceed 5 mg (0.1%).

Acid soluble matter: take about 1g of this product, accurately weigh it, put it in a 100ml conical flask with stopper, accurately add 20ml of dilute hydrochloric acid, weigh it, soak it at 50°C for 15 minutes, let it cool, and weigh it again. Make up the lost weight with dilute hydrochloric acid, shake well, filter through medium-speed filter paper, accurately measure 10ml of the continuous filtrate, add 1ml of dilute hydrochloric acid, evaporate to dryness, ignite to constant weight, and the remaining residue should not exceed 10.0% (2.0%). .

Ferric salt: Take 1ml of the filtrate under the pH check, add 1ml of dilute hydrochloric acid and 1ml of ferrocyanide test solution, and do not show blue immediately.

Weight loss on ignition: Take 2g of this product, ignite it at 600～700℃ to constant weight, the weight loss shall not exceed 5.0%.

Heavy metals: take 5g of this product, accurately weigh it, put it in a conical flask, add 25ml of 0.5mol/L hydrochloric acid solution, shake well, put it in a water bath to heat under reflux for 30 minutes, let it cool, filter it with medium-speed filter paper, and place 100ml of the filtrate. In the bottle, wash the container and the residue with 25ml of hot water in batches, filter, and combine the lotion into the same measuring bottle, let it cool, add water to the mark, shake well, and use it as the test solution.

Take 5.0ml of the test solution, put it in a 25ml Nessler colorimetric tube, add 2ml of acetate buffer (pH3.5), add water to dilute to the mark, and check according to the law (general rule 0821 method), the heavy metal content should not exceed 40mg/ kg.

Arsenic salts: Take 20ml of the test solution under the item of heavy metals, add 5ml of hydrochloric acid, and check according to the law (general rule 0822 method). Arsenic salts should not exceed 2mg/kg.

【Determination of content】

According to the titration method, titrate with disodium EDTA titration solution (0.05mol/L) until the solution changes from wine red to pure blue. This product contains no less than 88.0% magnesium silicate.

Care of talcum powder

Talc and talc powder should be stored in dry and airtight containers in a dry and cool place. Pay attention to moisture. Periodically check during storage.

After-sales service of talcum powder

Talc and talc can be stored for a long time under proper storage conditions. Can be used as long as there is no obvious deterioration.