1. Gold Chemical Properties Gold is chemically stable and has strong corrosion resistance. It is generally not oxidized from normal temperature to high temperature. Gold is insoluble in common acids and bases, but soluble in certain mixed acids, such as aqua regia. Gold may also be dissolved in an alkali metal cyanide, an acidic thiourea solution, bromine solution, boiling solution of ferric chloride, the presence of oxygen, potassium, sodium, calcium, magnesium thiosulfate solution or the like. Sulfides of alkali metals corrode gold to form soluble gold sulfide. Humic acids in the soil and metabolites of certain bacteria can also dissolve trace amounts of gold. Gold chemical data Atomic number 79 Position in the periodic table The sixth cycle, the first subfamily Atomic mass 196.9665 Stable isotope Au 197 Outer electronic structure 5d 10 68 1 Ion radius 0.137nm Atomic radius 0.144nm Ionization potential 9.19eV Gold has a high ionization potential, it is difficult to lose the outer electrons into positive ions, and it is difficult to accept electron anions. Its chemical properties are stable and its affinity with other elements is weak. Therefore, it exists in the elemental state in nature. Abundance of gold in various types of rock ( × 10 - 12 ) Rock class Magma rock Golden abundance Along the rock Golden abundance Metamorphic rock Golden abundance Deep rock Acidic granite 1.7 sandstone shale Carbonate Deep sea sediment 3.0 2.5 2.0 3.4 Mud slate and slate 1.0 2.2 neutral 3.2 Volcanic rock Acidity, basicity 1.5 More than 99% of the gold on the earth enters the core. This distribution of gold is formed during the long-term evolution of the Earth. The earth's crust formed in the early stage of earth development has a high abundance of gold. Therefore, it can represent the Archean greenstone belt composed of the early residual crust, especially the combination of mafic and ultramafic volcanic rocks, with high gold abundance. The various types of rocks in the earth's crust may become the earliest "mineral source" of gold deposits. Medium Temperature Masking Tape Wa Shi Tape,Washi Masking Tape,Bcp Washi Tape,Medium Temperature Masking Tape Ningbo Baichuan Adhesive Products Co., Ltd. , https://www.bcptape.com
The main chemical properties of gold are shown in the table below.
2. Gold geochemistry of gold having thiophilic, often in close symbiosis with the sulfides such as pyrite, arsenopyrite, galena, stibnite, and the like; easy to form an intermetallic compound with silver, copper and other elements of thiophilic .
Has pro-ferrous metal, the gold siderite (1150 × 10 -12) 3 orders of magnitude higher than the average rock, often gold intermetallic compound formation and PGE pro iron.
Gold is also pro-copper. It occupies the edge between the pro-copper and the pro-iron elements in the periodic table, and belongs to the same sub-group as copper and silver. However, in the reducing geological environment, the geochemical behavior and phase of gold The adjacent elements are similar, showing stronger iron-affinity, copper and silver are more concentrated in the sulfide phase; while gold-platinum is concentrated in the metal phase. The abundance of gold in the earth is 0.8×10 -6 , the core is 2.6×10 -6 , the mantle is 0.005×10 -6 , and the crust is 0.004×10 -6 . The abundance of gold in the earth's crust is only 1/10 million of iron and 1/21 of silver. The various types of rocks in the earth's crust are low in gold (Table below).
Granodiorite
Changyingyan
3.0
4.2
Shale
Schist
Gneiss
Quartzite
Carbonate rock
8.5
3.5
4.9
1.5
Basicity
Ultrabasic
4.8
6.6
Neutral
3.6
In summary, the abundance of gold in the earth's crust is inherently low, and it has the properties of sulfophilicity, pro-copper, pro-iron, high melting point, etc. To form an industrial deposit, gold must be enriched thousands of times. The formation of large ore and rich ore, gold is to be enriched by thousands, tens of thousands of times, or even higher, it can be seen that its large-scale gold mines generally have to undergo a long geological period, through multiple sources, multiple mineralization superimposed May form.