What is Friable Asbestos?

Asbestos cement tile is a layer-top waterproof material made of asbestos fiber and cement as raw materials and pressurized. From the specifications, it is divided into three types: large wave, medium wave, and wavelet. In addition, there are "herringbone" shaped roof tiles for covering the ridges that are matched with these three specifications. It is a roof waterproof material. It has the advantages of single leaflet and large effective area, fire resistance, moisture resistance, corrosion resistance, heat resistance, cold resistance and light weight.

Asbestos tiles are characterized by a large sheet area and a large effective utilization area. They also have characteristics such as fire resistance, moisture resistance, corrosion resistance, heat resistance, cold resistance, light weight, etc., and they are easy to produce, low in cost, and versatile ^.

In ancient China, asbestos was called "asbestos" or "non-grey cloth", which was used to make ropes and cloth.

Asbestos roof tile is a natural mineral, which can be divided into two categories: fiber serpentine asbestos and amphibole asbestos according to its generation. The most common type of asbestos we use is fiber serpentine asbestos. This type of asbestos is also called chrysotile. Chrysotile is a magnesium silicate containing crystal water. Because chrysotile has good fire resistance, alkali resistance, high pit tensile strength, small bulk density and good adsorption capacity, asbestos can be well combined with cement. Some of our common simple roofs are built with corrugated asbestos cement tiles. In addition, many factories also use asbestos tiles in order to consider fire prevention.

Asbestos shingles account for about 15-20% of warm asbestos and 80-85% of ordinary portland cement. They can be firmly combined, so they do not contain asbestos dust flying and harm to the human body. The harm of asbestos to people is mainly caused by the asbestos dust flying in the process of asbestos mining, transportation and production. Such as automobile brake pads, dust generated by friction on the environment will have a certain impact on the environment, of course, it will also endanger human health. ^[2]

The classification according to the state of raw ore can be divided into the following:

Serpentine (chrysotile, white asbestos)

Chemical formula: Mg6Si4O10 (OH) 8. It is named for its cotton-white appearance.

Hornblende (blue asbestos)

Chemical formula: Na2Fe5Si8O22

Brown asbestos (tea asbestos)

Chemical formula: Na2 (Fe2 + 3Fe3 + 2) Si8O22 (OH) 2. The fibers are pointed and needle-like, have less flexibility, and have the strongest toxicity. They were banned from production and manufacture in 1995.

Amphibole

Chemical formula: Mg7Si8O22 (OH) 2

Amphibole

Chemical formula: Fe2 + 7Si8O22 (OH) 2 series (iron asbestos): production and manufacturing have been banned in 1995.

Anthracite includes:

Amphibole (through-angle amphibole)

Chemical formula: Mg7Si8O22 (OH) 2

Tremolite (yang asbestos)

Chemical formula: Ca2 (Mg, Fe) 5Si8O22 (OH) 2 (Mg / (Mg + Fe) = 1.0-0.9)

Amphibole

Chemical formula: Ca2 (Mg, Fe) 5Si8O22 (OH) 2 (Mg / (Mg + Fe) = 0.5-0.9)

Asbestos shingles are used as building roof materials, heat insulation and sound insulation materials, and are used in buildings, ships, railway vehicles, etc.

Materials for gaskets, brake pads, clutch plates, and insulation of vehicles.

It was discovered in 1970 that asbestos fibers are harmful to the human body. Inhaling asbestos dust will not only cause fibrosis in the lungs and cause pneumoconiosis, but also induce bronchial lung cancer, pleural and mesothelioma, and other malignant tumors.

France and Canada sparked a trade and environmental war over the asbestos regulations.

France began to restrict the import and use of chrysotile asbestos on January 1, 1997. However, in order to maintain the product market in Canada (the third largest asbestos producer in the world, exports of chrysotile asbestos account for 97% of the total mining volume). "As long as it is used correctly, the product is still safe", the French government was accused of irrational actions to the WTO's Trade Barriers Committee and asked France to abolish the ban.

In March 2001, the WTO made a landmark ruling that since chrysotile asbestos has been identified as a carcinogen, the safe use limit that asbestos manufacturers insist on does not exist.

Legalizing the rights of WTO members to ban the use or import of carcinogens such as asbestos, and further confirms that WTO members have the right to believe that protecting lives and health is more important than fulfilling trade obligations.