Glass is divided into ordinary glass and crystal glass, and crystal glass is divided into lead-free crystal glass and lead-containing crystal glass. So how do we identify lead-free glasses?

The method is actually very simple. We can distinguish lead-containing glass from lead-free glass by looking at weight, logo, color and heat resistance.

How to identify lead-free glass by valve

1, look at the logo: lead-free glass generally contains potassium, mostly high-grade handicrafts and has a logo on the outer packaging; Lead-containing glass contains lead, which is a common crystal glassware in some supermarkets and stalls, and its lead oxide content can reach 24%.

2, look at the color: lead-free glass has better refraction than traditional lead-containing crystal glass, which perfectly shows the refraction performance of metallic glass; For example, some ornaments of various shapes, crystal wine glasses, crystal lamps and so on. It is made of lead-containing glass.

3, look at heat resistance: glasses can generally withstand high temperatures, but generally have poor resistance to extreme cold and extreme heat. Lead-free crystal glass is a kind of glass with high expansion coefficient, and its extreme cold resistance and heat resistance are worse. If you make tea with boiling water in an extremely cold lead-free glass, it will burst easily.

4. Weight: Compared with lead-free crystal glass products, lead-containing crystal glass products are slightly heavier.

5. Listening to the sound: Beyond the metallic sound made by lead-containing crystal glass, the sound of lead-free glass is better, and it is known as the "music" cup.

6, look at toughness: lead-free glass is more toughness than lead-containing crystal glass, that is, impact resistance.

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Do ordinary glasses contain lead? How to judge?

How to judge whether crystal glass contains lead?

Using crystal tableware to hold food and drinks looks gorgeous and makes people fondle it. But many people can't imagine that if a cup made of artificial crystal containing lead is used to hold acidic drinks such as honey, it will cause lead pollution and seriously endanger health.

Lead poisoning patients-mostly use crystal glasses.

According to Professor Zhu, director of the Poisoning Department of West China Fourth Hospital of Sichuan University, many lead poisoning patients in the poisoning department of this hospital use crystal glass containers to drink acidic drinks.

Crystal products-a threatening lead pollution source

Experts say that crystal products are a threat source of lead pollution. The content of lead oxide is often as high as 20% ~ 30%. When it is used to hold water, it will not cause lead poisoning. However, if it is used for wine or acidic drinks, the lead in crystal products will precipitate and dissolve in wine or acidic drinks. Experiments show that the longer the wine is stored, the higher the lead content in the wine.

In addition, foreign experiments have proved that the lead content of 65,438+0 liters of brandy can be as high as 20,000 μ g/L after being placed in crystal vessels for five years, far exceeding the requirement of environmental protection departments that the lead content in beverages should be lower than 50 μ g/L. ..

Lead poisoning-more harmful to children

According to the regulations of the World Health Organization, if a person's blood lead level is greater than 100 μ g/L, it belongs to lead poisoning. When lead in the blood accumulates to a certain extent, it will make people's memory and intelligence decline, resulting in mental disorders, nightmares, insomnia and other problems.

Lead poisoning is more harmful to children and easily leads to mental retardation. Therefore, it is necessary to avoid storing alcohol, fruit juice or acidic drinks with crystal products for a long time, so as to avoid poisoning due to lead accumulation and damage to health.

How to judge whether crystal glass contains lead?

Appearance and feel can be distinguished.

Buying crystal glass tableware can distinguish glass, lead-containing crystal glass and lead-free crystal glass by sound, feel and appearance.

Ordinary glass products are dull in color, poor in refractive index, rough in workmanship, poor in hand feel, and even have bubbles in some places, and the sound of tapping lightly is dull.

Compared with ordinary glass products, crystal glass products have bright colors, strong refractive index, exquisite workmanship and good hand feel. They look like crystals, and when tapped, they make a crisp metallic sound. Compared with lead-free crystal glass products, lead-containing crystal glass products are slightly thicker.

The glass with lead looks like crystal.

Glass containers in circulation in the market can be divided into ordinary glass containers and crystal glass containers according to their materials.

There are two kinds of crystal glass containers: lead-free crystal glass and lead-containing crystal glass. Because the color, texture and gloss of ordinary glass are not ideal. Adding lead to glass can greatly improve the refractive index of glass, which looks like crystal, so it is called crystal glass. Some decorations of various shapes, crystal glass, crystal lamps and so on are made of lead-containing glass.

The state has no relevant standards. At present, there is no national standard for crystal glass in China. Because there is no national standard, many enterprises make their own enterprise standards for production, but most enterprises refer to EU standards for production.

In EU standards, crystal glass is divided into lead-free, lead-containing and high lead. The lead oxide content of lead glass reaches 24%; The lead oxide content of high lead glass reaches 36%.

If crystal glass containers are produced according to EU standards, no matter what kind of products and the lead content, there are strict regulations in the world, which should be safe for human body. However, due to the lack of domestic standards, it is not excluded that individual manufacturers produce at will, and the product quality is difficult to guarantee.

Toxicology knowledge

Harm of lead

In daily life, if the cup made of artificial crystal containing lead is filled with acid drinks such as alcohol, cola, honey, fruit juice or other acid foods, lead ions may form soluble lead salts, which will be ingested by the human body with the drinks or foods, seriously endangering health.

▲ Lead mostly passes through the blood-brain barrier in the form of free or inorganic compounds, which is harmful to the vascular-rich central nervous system-hippocampus and cerebral cortex.

▲ When the blood lead concentration reaches 30 μ g/L, women will have neurotoxic reactions such as general weakness, dizziness, headache, anemia, memory loss, muscle joint pain, constipation and irregular menstruation.

▲ Symptoms such as arteriosclerosis, digestive tract ulcer and fundus hemorrhage are also related to lead pollution.

▲ When the blood lead level is high, the patient's mouth has a metallic taste, and the water in the patient's blood vessels penetrates into the brain matrix ... >>

How to distinguish lead-free glass from lead-free glass

Glass containers in circulation in the market can be divided into ordinary glass containers and crystal glass containers according to their materials. There are two kinds of crystal glass containers: lead-free crystal glass and lead-containing crystal glass. The lead-free glass we usually see refers to lead-free crystal glass.

Characteristics of crystal glass

Compared with ordinary glass products, crystal glass has bright color, strong refractive index, exquisite workmanship and good feel. It looks like crystal, and it makes a crisp metallic sound when tapped lightly. That's because lead is added, so it's also called leaded glass. Widely used in glass crafts and decorations.

Lead-free glass crystal glass products are slightly thinner than lead-containing crystal glass products, which are characterized by inheriting the appearance quality of lead-containing crystal glass and containing no lead, so they are also called non-toxic glass. Widely used in high-grade porcelain, tableware and wine sets.

Characteristics of ordinary glass

Ordinary glass products are dull in color, poor in refractive index, rough in workmanship, poor in nail feeling, and even have bubbles in some places, and the sound of tapping will be dull. Its advantages are lead-free and non-toxic. Widely used in food glass containers and medical devices.

How to identify whether glass contains lead?

Determine by measuring the density of glass. The density of ordinary glass is 2.5-2.56, and the density of lead-containing glass is much higher than 2.56.

How to identify whether glassware contains lead?

It is difficult for laymen to tell by visual inspection alone. But at present, almost no one adds lead to household utensils, and now there are other substitutes, which are inexpensive, effective and healthy.

How to judge whether glass contains lead? How to judge ordinary glass and lead-containing glass?

I looked up many methods and found that it was not easy to draw a clear conclusion. After careful consideration, I designed a simple and feasible judgment method with the chemical knowledge I learned:

Need tools: electronic scale accurate to G+ water

Method:

Weigh x grams of glass.

Try to fill a tall container with enough water.

Completely immerse the cleaned and unwashed glass in water and mark the water with a pen.

Squeeze out the glass and try to keep the water in a thin container.

Take a large paper cup of water, and weigh one gram of paper cup and one gram of water electronically.

Pour the water in the paper cup into the thin container until the water level reaches the scale.

Weigh the remaining paper cups and water b grams, y = a-b.

Then the percentage of lead content is:130 (x-2.2y) ÷ X.

(Premise: Glass only contains glass and lead, without considering other impurities)

How to judge whether glass contains lead?

Do you mean glass plates (such as window panes) or glass products (cups, handicrafts)? Different methods.