Gold Extraction

Written By latifah gurape on Monday, December 24, 2012 | 8:23 AM

Amalgamation

Amalgamation is the process penyelaputan gold particles by mercury to form amalgam (Au - Hg). Amalgam is still the gold extraction process the most simple and inexpensive, but effective process for high-grade gold ore and has a coarse grain size (> 74 microns) and in the form of pure gold that is free (free native gold).
The process of amalgamation is the process of physical chemistry, amalgamnya when heated, it will decompose into elements, namely mercury and gold bullion. Amalgam can be decomposed by heating in a retort, the water will evaporate and the mercury can be recovered from the condensation of mercury vapor. While the Au-Ag still remains in the retort as metal.

Cyanidation

Cyanidation process consists of two stages of importance, namely the dissolution process and the process of separating the gold from the solution. The solvent used in the process is cyanidasi NaCN, KCN, Ca (CN) 2, or a mixture of all three. Solvents most commonly used is NaCN, being able to dissolve gold better than other solvents. In general, Au and Ag dissolution reactions are as follows:

4AU + 8CN-+ O2 + 2 H2O = 4AU (CN) 2 - + 4OH-
4AG + 8CN-+ O2 + 2 H2O = 4AG (CN) 2 - + 4OH-

In the second stage of the separation of the gold from the solution made by deposition using Zn powder (Zinc precipitation). The reaction is as follows:

2 + 2 NaAu Zn (CN) 2 + 4 NaCN Au +2 H2O = 2 NaOH + 2 + 2 Na2Zn (CN) 4 + H2
2 + 2 NaAg Zn (CN) 2 + 4 NaCN +2 H2O = 2 Ag + 2 NaOH + 2 Na2Zn (CN) 4 + H2

The use of Zn powder is one effective way to solutions containing small concentrations of gold. Zn powder were added to the solution will precipitate the metals gold and silver. The principle is based deposition Clenel series, which is based on differences in the chemical sequence of electrical activity of metals in cyanide solution, namely Mg, Al, Zn, Cu, Au, Ag, Hg, Pb, Fe, Pt. any metal that was left of the complex bond sianidanya can precipitate metal it replaces. So it was not just to urge Zn Au and Ag, but Cu and Al can also be used, but because it is more expensive then better to use Zn. Making process of the gold-silver rich solution using Zn powder is called "Merrill Crowe Process".

The World Bank (English: World Bank) is an international financial institution that provides loans [2] to developing countries for capital programs.

The World Bank's official goal is the reduction of poverty. According to the World Bank's Articles of Agreement (as amended, effective as of February 16, 1989) all decisions must be guided by a commitment to promote foreign investment, international trade and facilitate capital investment. [3]

Unlike the World Bank Group The World Bank (World Bank Group), in which the World Bank comprises only two institutions: the International Bank for Reconstruction and Development (International Bank for Reconstruction and Development) (IBRD) and International Development Association (International Development Association) (IDA ), while the World Bank Group includes the two institutions plus three more: [4] International Finance Corporation (IFC), Multilateral Investment Guarantee Agency (MIGA), and International Centre for Settlement of Investment Disputes (ICSID).

Operation of the World Bank maintained through payments as regulated by member states. The World Bank's current activities are focused in areas such as education, agriculture and industry. The World Bank provides loans with preferential rates to member countries who are in distress. In return, the Bank also requested that the economic measures must be taken to, for example, corruption can be limited or democracy developed.

The World Bank Founded on December 27, 1945 after the ratification of international agreements reached at the conference which took place on 1 July to 22 July 1944 in the town of Bretton Woods. The World Bank headquarters in Washington, DC, USA. Technically and structurally World Bank is one of the UN agencies, but operationally quite different from other UN agencies.

Financial institutions in the financial world to act as an organization that provides financial services for its customers, which in general is governed by regulatory agencies of the government's finances. The general form of the financial institutions are including banking, building society (a type of co-operatives in the UK), Credit Union, stockbroker, asset management, venture capital, cooperatives, insurance companies, pension funds, and other similar businesses.

Financial institutions in Indonesia is divided into 2 groups: the banks and financial institutions Non-bank financial institutions (insurance, mortgages, pension funds, mutual funds and stock exchanges).


function

These financial institutions provide services as an intermediary between the owners of capital and debt markets is responsible for channeling funds from investors to companies in need of funds. The presence of these financial institutions that facilitate the flow of circulation of money in the economy, where the money collected from individual investors in savings so that the risk of these investors turn to financial institutions who then distribute these funds in loans owed to the needy. This is the main objective of the institution to generate income depositors. An example of a financial institution is a bank.

Pesticides are chemical substances and other materials and microorganisms and viruses used to control various pests. The definition of pest is very broad here, namely insects, mites, plant pest, plant diseases caused by fungi (mushrooms), bacteria and viruses, and nematodes (worm-like shape with a microscopic size), snails, mice, birds and other animals are considered harmful.

BBagi domesticity, which is pest is covering all animals that jeopardizes the welfare of her life, such as flies, mosquitoes, cockroaches, moths, beetles, snails, ticks, mites, caterpillars, termites, algae and other life were shown to interfere with well-being.

Pesticides are also defined as chemicals and other substances that regulate and or stimulate the growth of plants or plant parts. As per the concept of Integrated Pest Management (IPM), pesticide use is not intended to eradicate or kill pests, but more dititiberatkan to control pests in such a way as to be below the economic threshold or threshold control.

In Indonesia for crop protection, particularly for agriculture and forestry in the year 2008 to the first quarter 1702 was recorded formulations that have been registered and permitted uses. While the active ingredients listed have reached 353 species.

In an integrated pest control, pesticides are a last alternative. And learn from experience, the government is no longer providing subsidies to pesticides. But the reality on the ground many farmers still use it. Responding to this, it is important to both government and private sector continue to provide counseling on how to use pesticides safely and properly. Secure against themselves and their surroundings, right in the sense of a proper 5 (the right kind of pesticide, on how the application, effective, timely, and appropriate dosing).
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