Glazing using granite waste

Granite is one of the most widely distributed and resource-rich rocks. For a long time, people have continuously extracted it, cut and processed it into plates, and are widely used for interior and exterior decoration of buildings. However, during the mining and cutting process, a large amount of granite chips and cutting dust are discarded as waste. This is actually a waste of resources. In fact, granite waste has great use value. This is because granite is an igneous rock with a SiO2 content of more than 65%. It is mainly composed of feldspar, quartz and mica minerals. Granite waste is used as a substitute for feldspar and quartz in the ceramic industry. Used to produce glazes. According to reports, this waste recycling technology has been successful overseas. The following is a description of the waste recycling technology.
First, the preparation of granite powder Granite powder is used granite mining and cutting process emissions of debris and powder to prepare. Table 1 lists the chemical composition of the granite used. Because of the different size of granite chips and powder, different grinding methods are used to prepare powders: When using granite chips, granite chips and water are first wet-milled in a ball mill and then placed in containers. Precipitate drying; When using granite chips, first smash the chips with a press into powder form, or heat it to about 1000°C, quench and brittle, pulverize into powder, and then wet-grind ball-milling to precipitate in the container. dry. Due to the hardness of granite, it is not appropriate to use a porcelain grinding body for wet grinding. Instead, it can be replaced with natural granite chips instead of ceramic balls. The resulting powder can be formulated into a glaze.
Second, the glaze preparation Through research shows that only with granite powder can also be prepared glaze. According to the firing test, using the plug format calculations, add lime or silica to compensate for CaO deficiency or adjust the Al2O3/SiO2 ratio.
3. Glaze Burning Test The glaze was applied to a china dish and sent to an electric furnace and fired at 1230°C.
In the other conditions under tests 1 to 6, the results when 2% Fe2O3 was added were as follows: Test 1 was a reddish-brown opaque glossy glaze; Test 2 was a low-brightness magnolia-colored semi-gloss clear glaze; Test 3 was a dark brown opaque luster glaze; Test 4 is a highly transparent magnolia gloss glaze, and test 5 is a magnolia translucent glaze: Test 6 is the same as Test 3, but the glaze shrinks greatly. The results of addition of 5% Fe2O3 were as follows: Tests 1, 3, and 6 were dark bean sand-colored opaque glazes, in which 3 and 6 had a larger shrinkage; Test 2 a thin oil portion was a brown glaze, and a thick glaze portion was a black luster glaze; The thin oil part is a yellow glaze, the thick glaze part is a dark brown transparent gloss glaze, and the test 5 is a black daylight glaze. The results of the addition of 10% Fe2O3 are as follows: Tests 1 and 3 are black glazes, and the surface contains fine crystals of scintillating light; Test 2 is a bright glaze that grows green and brown crystals on the red-brown background; Test 4 is for thin oil Bright brown glaze, thick glazed part with a transparent black glaze. Test 5, which approximated the state of test 2, appeared brown. Test 6 shows dark spots appearing on the dark brown background.
Based on the above results, the following conclusions are drawn:
1, using 100% granite powder, can also be prepared glaze;
2, using granite as the main raw material, adding 30% or less of lime or silica, adjust the formula, can be prepared similar to transparent glaze, celadon glaze and other glaze;
3. When using granite dust, even if it contains abrasive, it will have no effect on glaze.
4, through the granite particle size changes, can make color and glaze produce a variety of changes;
5, adding black mica can be prepared iron glaze such as Tianmu glaze;
6, add iron, copper, zirconium and other coloring metals, can be prepared iron glaze, gold sand glaze, glaze glaze, sulfur glass glaze and so on.
7. Adding granite powder or biotite to ceramic raw materials can produce granite-like ceramic products.
In short, the development and application of this technology will not only help protect and save resources, but also open up a new path for the use of granite waste, with good social and economic benefits.