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Gold

Gold

Release time:22 August 2019
pure gold

Type
Element (Minerals/Ores of)

Mineral Classification
Native

Chemical Formula
Au

Streak
Shining yellow

Mohs Hardness
2.5-3

Crystal System
Isometric

Color
Gold

Luster
Metallic

Fracture
Jagged

Description

Gold (element #79, symbol Au) is a heavy, shiny yellow metal. It is probably the oldest precious metal known to humans. Wars have been fought over it and countless numbers have died trying to gain it or protect it. Its physical and chemical properties make it ideal for a number of applications. It is used in dentistry and medicine, in jewelry and arts, in medallions and coins, in ingots as a store of value, for scientific and electronic instruments, and as an electrolyte in the electro-plating industry. South Africa has about half of the world’s gold resources. Significant quantities are also present in the U.S., Australia, Brazil, Canada, China, and Russia.

Relation to Mining

Gold is found in two major types of deposits. Lode deposits are where gold is found in veins in the rock. The second type is called a placer deposit that is formed by moving water that has eroded gold out of lode deposits. When the speed of the water in a river slows sufficiently, the heavy gold falls to the bottom and accumulates in the sand of the riverbed. Another source of gold is as a by-product of copper and silver mining. Gold is so valuable that it is worth the effort to recover even minute amounts from copper and silver ore.

It is estimated that the total amount of gold yet to be removed from the Earth is 100,000 tons. South Africa is the world’s largest producer of gold and is estimated to have half of these gold resources. The United States and Brazil each have significant amounts of the world’s gold resources. Approximately one-fifth of the total resources of gold in the world are by-products from copper and silver ore processing.

In the United States, Nevada produces the majority of the gold followed by Alaska. The remaining gold deposits are in other western states. Most of the gold recovered in the United States is produced from only about 30 mines. Brazil and Canada export significant amounts of gold to the United States.

Uses

Most gold is used to make jewelry and other art items. Because it is chemically stable and conducts electricity so well, it is very important in electronics. Electronic applications represent a significant amount of the United States’ annual gold consumption, followed by dentistry and a variety of other applications.

Gold has been very important as the standard for currency. In 1792, the United States Congress established gold and silver as the standard for the nation’s money. The U.S. Department of the Treasury holds a major stockpile of gold.

Related cases

Gold Beneficiation Methods

Rock gold beneficiation

The mainstream gold beneficiation process flow is generally crushing – grinding – gravity separation – flotation – chemical – smelting.

Gravity separation process and flotation are the most used gold mining methods around the world.

Gravity separation

Gravity beneficiation is refers to separating gold ore according to mineral density and plays an important role in contemporary mineral processing methods. The main gravity separator equipment are chute, shaker table, mineral jig, hydrocyclones, etc.

Gold flotation

Flotation process is widely used for lode gold processing. In most cases, the flotation method has a good effect in sulfide-containing gold ore with high floatability.

In addition, the flotation process is also used for polymetallic gold-bearing ores such as gold-copper, gold-lead, gold-copper-lead-zinc-sulfur ore.

What’re the limitations of the flotation method? For the ores with particle size greater than 0.2mm, and the quartz gold-bearing ore containing no sulfide, it is not suitable to use the flotation method.

Chemical method

There are amalgamation gold extraction process and cyanide process gold extraction.

The amalgamation process is an old gold extraction process, simple and economical, suitable for the recovery of coarse-grained monomer gold, but it has pollution to the environment and is was gradually replaced by gravity separation, flotation and cyanidation process.

The cyanidation gold extraction process includes cyanide leaching, cyanide pulp washing and filtration, extraction of gold from the cyanating solution or cyanide pulp, and smelting.

Heap leaching

Among the gold resources, the amount of low-grade oxidized ore occupies a certain proportion. It is not economical to use the cyanide method to extract gold, and the heap leaching process has economic benefits.

The heap leaching method actually deposits gold-bearing ore on an impervious site and is immersed and leached with a cyanide solution. After dissolving the gold and silver in the ore, the pre-designed grooves along the site flow into the storage tank. The gold-silver-containing liquid is carbon-adsorbed with activated carbon and then desorbed to recover gold and silver.

Placer gold wash plant

Placer gold process

The gold content in the placer gold mine is extremely low, and it is known as the gold panning by beneficiate the placer gold through various energy-efficient placer gold equipment.

Among various gold extraction methods, the gravity separator method is energy-saving, efficient, environmentally friendly, and is suitable for placer gold ore process.

Placer gold mine mining

The placer gold deposits are usually mined by gold dredger, hydraulic mining, excavation and underground (shaft) mining.

Placer gold wash plant

–Ore washing. Separate gravel, sand and soil, wash the fine mud adhering to the gravel.

–Screening. Screening the cleaned alluvial gold ore to remove large pieces of gold-free stones will help improve the gold beneficiation efficiency.

–Gravity separation. Coarse gold concentrates are available in the process, so the gravity separation process directly affects the results of the entire placer gold beneficiation.

–Concentration. According to different types of alluvial gold mines, gravity separation amalgamation, etc. can be used to further increase the gold concentrate content.

Placer gold panning equipment

vibrating screen, trommel scrubber machine, sand washing machine, chute, jig concentrator, gold shaker table, etc.

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