Characteristics and types of talc mineral raw materials

First, the characteristics of ore mineral raw materials

The theoretical composition of the talc mineral is MgO = 31.72%, SiO2 = 63.12%, and H2O = 4.76%. The silicon contained is sometimes replaced by aluminum or titanium (up to 2% for aluminum and 0.1% for titanium), and magnesium is often replaced by iron, manganese, nickel and aluminum. It contains FeO up to 5%, Fe2O3 up to 4.2%, and NiO up to 1%. Some contain a small amount of potassium, sodium, and calcium. Substituting the isomorphism can form talc variants with different compositions, such as iron talc Fe3[Si4O10](OH)2, calcite Ca3[Si4O10](OH)2, nickel talc Ni3[Si4O10](OH)2 and the like.

 

Talc belongs to the orthorhombic column crystal. The fine crystals are hexagonal or diamond-shaped, but rare. It is usually a dense block, leaf or scaly aggregate.

Pure talc is white or slightly yellowish, pink, light green, and light brown. Talc with a darker color is caused by impurities. Glass luster, dense block talc is a shell-like fracture with a hardness of 1. and a density of 2.58-2.83 g/cm3. Talc has a smooth feel and high electrical insulation.

According to the use, talc mineral raw materials can be divided into two types, namely, block talc and talc powder. The color of the block talc used for carving crafts can beautify, so the impurity-induced coloring element is a beneficial component here. Talc powder for paper and chemical industry requires whiteness. Therefore, the coloring element impurities such as iron, manganese, nickel and titanium contained are harmful components.

Pure talc ore is rare and usually associated with other minerals such as chlorite, magnesite, tremolite, dolomite, siderite, quartz, pyrite. These minerals alter the chemical composition of the ore, coloring the ore, and significantly affecting the physical properties of the ore, which in turn reduces its industrial grade.

Second, the type of talc mine

Can be divided into 4 categories abroad:

1, block talc . It is dense and can be processed into blocks of different shapes of a certain size. Less impurities, talc content of more than 70%.

2. Flaky soft talc . It is an alteration product of magnesium carbonate rock, and the common associated mineral is chlorite. This is the most versatile ore.

3. Tremolite talc . Sometimes called hard talc, it is a rock in the form of a block or layer. Contains different amounts of tremolite, amphibole, calcite, dolomite, serpentine and other associated minerals. This ore is characterized by a high calcium oxide content of 6% to 10%.

4. Mix talc . It is a kind of flaky rock containing talc, dolomite, calcite, serpentine, chlorite, etc. It is white and brittle.

In China, it is divided into block talc and talc according to the content of talc. The latter has a talc content of less than 70%, which needs to be used for beneficiation. The talc rocks are mainly talc chlorite rocks and talc carbonate rocks. In addition to chlorite and talc, talc chlorite is often accompanied by serpentine, pyroxene, etc. Most of the color is green. The talc carbonate rock associated with talc is magnesite or dolomite, and the color is mostly light gray.

China has a long history of mining and utilizing talc, which was used for engraving as early as the primitive society. Before the founding of New China, there were only a few talc mines in China, and the amount of mining was small and the production methods were backward. After the founding of the People's Republic of China, a large-scale census exploration geological work was carried out nationwide, and many new talc deposits and ore deposits were discovered, with more than 20 major mines. For example, the Haicheng talc mine in Liaoning Province, which has the largest mining scale and long history, enjoys a certain reputation abroad. Secondly, there are Benxi, Yingkou and Huanren in Liaoning, Jixian, Pingdu, Haiyang, Qixia in Shandong, Longsheng in Guangxi, and talc mines in Suining in Sichuan all have a certain reputation.