In addition to gold gold sand sand, also contains many kinds of heavy mineral. Heavy mineral placer associated with the common-ness may be arranged according to the following: magnetic iron ore, iron titanium, rutile, garnet, zircon, pyrite, monazite ....... The gold particles are mostly granular or scaly, and their particle size is usually 0.5 to 2 mm, but it also has a weight of several kilograms, and there are powdery gold particles that are discernible to the naked eye. The gold color is usually 850-900, and the specific gravity is 17.5-18.0. Gold is divided into: according to the particle size: 1. large gold nuggets - greater than 5 mm; 2. coarse gold nuggets - 1.65 ~ 5 mm; 3. medium gold - 0.83 ~ 1.65 mm; 4. fine gold - 0.42 ~ 0.83 mm; 5. Particulate gold - 0.15 ~ 0.42 mm; floating gold - less than 0.15 mm.
Gold is mainly selected by gravity method. This is because the re-election method is simpler and more economical than other methods, and because the sand gold ratio is large and the particles are coarse, it is easy to sort by re-election. Mercury amalgamation , flotation, and other methods are mostly used to separate re-concentrated concentrates. Re-election equipment uses a variety of chutes, jigging and shakers, spiral and centrifugal concentrators .
The characteristics of sand gold are as follows: 1. The gold content is low, generally greater than 0.2-0.3 g/ m3 , and the heavy mineral (mine with a specific gravity greater than 4) is about 1-3 kg/ m3 ; 2. The maximum particle size and minimum amount of gangue The ratio of particle size is several thousand; 3. The yield of concentrate is very small (usually not more than 0.1-0.01%); 4. The ratio of ore dressing is particularly high (nearly thousands to 10,000 times); 5. The coarse concentrate has to be refined several times. In order to obtain gold and qualified heavy sand concentrate.
The typical process for sand gold sorting is shown below.
Silicone mould is a special mold for making crafts. According to performance, the raw materials of glue can be divided into ordinary silicone and weather silicone. The characteristics of silicone are high temperature resistance, corrosion resistance, strong tear resistance, high simulation precision, and it is used to make various handicrafts mold.
Mold should be made in time after the silicone is matched. Pour the glue on the highest part of the mold in a trickle, let it flow naturally, brush it in place with an oil paintbrush where the flow is not in place, if it is a piece of silicone, not only fill the entire product, but also brush the glue evenly. Each product should be brushed with at least three layers of silicone. The thickness of each layer of silicone is 1mm. In the process of brushing the silicone, each layer is required to be cured before the other layer can be brushed. When brushing the third layer, add one layer on top of the second layer. The thickness of the silica gel part of the whole mold is controlled in 3-4mm according to the different requirements of the size of the product, and the width is not greater than 60 mm of the product width. The time for the silicone to set is 20 minutes.
Silicone Injection Molding, Moulding Silicone, Rubber Molds, Rubber Mold Making
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