Gold has very little content in nature, and the elemental Clark value in the earth's crust is only 5 × 10 -9 . However, due to the extremely uneven distribution in the earth's crust, the enrichment in some areas has resulted in deposits with mining value.
Under native conditions, gold is present as a complex of sulfur and chlorine. There is a view that hydrosulfides in hot aqueous solutions are highly soluble at temperatures above 50 ° C, and they migrate by means of hot aqueous solutions. Under suitable conditions, the gold complex chemically reacts with iron to form precipitated gold:
2Na 3 AuS 3 +3FeCO 3 →2Au↓+3FeS 2 +3Na 2 CO 3
Under oxidizing conditions, such as chloride in the surrounding rock, it dissolves gold and is adsorbed by sulfide and quartz precipitated simultaneously with gold, resulting in secondary enrichment of gold and formation of a gold-bearing deposit.
In general, gold is insoluble, and gold is often left in the oxidation zone. After enrichment or primary gold ore is weathered, denuded and redeposited, various types of gold deposits are formed.
Gold is a sulfur-rich element. Under the original conditions, gold minerals often coexist with sulfide minerals such as pyrite and arsenopyrite, but never form sulfides with sulfur, and are not combined with oxidation. It exists mainly in the natural gold of the elemental state.
There are more than 20 kinds of gold minerals in nature. There are:
(1) Natural gold (Au). Natural gold is often in the form of granules, flakes and other irregular shapes. Large natural gold nuggets can weigh up to tens of kilograms, and small, finely dispersed fine gold particles in ore can be as small as 0.1 micron or finer. Natural gold minerals are not chemically pure and often contain impurities such as Ag, Cu, Fe, Te, Se. However, as the impurity content increases, the specific gravity decreases. The natural gold has a specific gravity of 15.6 to 18.3 (pure gold specific gravity of 19.3) and a hardness of 2 to 3; it has a certain magnetic property due to iron impurities, and the crystal structure is a metal lattice.
The most common impurities in natural gold are Ag, Cu and Fe. Usually, the content of Ag is 5% to 30%, up to 50%, Cu is 1.5%, and Fe is 2%. Although natural gold contains elements such as Cu and Ag, it is not a true alloy. It has a special structure and unevenness and is formed by the deposition of a hot aqueous solution rather than a solid.
(2) Gold minerals containing silver . Because the atomic radii of gold and silver are similar, the lattice structure is of the same type and the chemical properties are similar. When the amount of silver in natural gold is constant, it can be called silver gold ore (Ag content). Au) (also home silver minerals), native silver gold, silver, copper, gold and other natural minerals metals.
Mineral composition (3) gold and platinum group elements. Gold may be formed of palladium (palladium 11.6%) when mixed with mineral native gold a considerable amount of platinum group element (in isomorphous mixed), platinum mine (10% platinum), gold iridium (iridium-containing 30% ) and platinum-silver gold ore, palladium-copper-gold ore, etc.; when the gold elemental substance is mixed into the platinum group element mineral, it can also be called platinum palladium ore and uranium gold antimony ore.
(4) bismuth gold mine. A mineral formed by the combination of gold and strontium under certain geological conditions. When containing é“‹ 4%. It is a solid solution, and when it contains more than 4% of cerium, it is a mixture of solid solution and natural cerium, and its properties are similar to those of natural gold.
(5) Minerals composed of gold and antimony . The compounds composed of gold and strontium are AuTe 2 (AuTe 2 ), bright gold deposits, acupuncture gold and silver deposits, bismuth gold and silver deposits, and eucalyptus gold deposits.
(6) Gold ore (AuSb 2 ). Gold and bismuth compounds.
The most common major minerals are natural gold, followed by silver gold and gold.

Screen Printing Machine:

Our Silk Screen Printing Machine is a kind of syringe printing machines. It is used to print the scale line and logo on the syringe barrel. There are two types for our syringe silk screen Printing Machine, one is QZ-216 with vibrate feeder and the other is QZ-226 with centrifugal feeder. Both can print different syringe sizes on one machine by changing its screen version and adjusting the machine accordingly.

Technical Parameter:

Name: Syringe Silk Screen Printing Machine

Dimension: 4600*1200*2050mm

Weight: 600kg

Production Speed: 120 pieces/minute

Silk screen printing machineSilk screen printing machine-1

 

FAQ:

1. Are you a manufacturer?

Yes, we are the professional manufacturer set up in 1992, located at a beautiful town of Zhejiang Province.

2. Can you provide the oversea service?

Yes, after the machines arrive at your factory, we will arrange engineers go to install the machine and train your operators.

3. Can we visit your factory?

Of course. We highly welcome clients come to visit our factory. It will be our great honor to meet you.

4. How can you guarantee the quality?

100% qualified products before the delivery. The clients can inspect the products at our factory.

1 year warranty ( failure caused by machine quality ) from the equipment arrive at the client`s factory. Lifetime maintenance and offer for the spare parts.


Screen Printing Machine

Screen Printing Machine,Silk Screen Printing Machine,Syringe Screen Printing Machine,Screen Printing Equipment

Yuhuan Zhengri Technology Co., Ltd. , http://www.syringemachine.com