الفهرس 
Solubilization of the metal from soil matrix
Procedure for a gold phytomining operationOnly 14 pages are availabe for public view
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Abstract
Some plants have the remarkable ability to accumulate metals in their tissues from the soil in which they are grown. Conventional mining is usually performed from the ores that have a high concentration of target metal and requires huge capital investment. To be economically viable, such operation requires ore bodies with sufficient ore deposits. phytomining technology is the most feasible, economically acceptable, environmentally sound, and supplementary as well as an alternative plant based technology for exploiting and recovering the precious metals from low grade surface ores or mineralized soils.
Past mining operations, however, environmental risk in the form of chemicals, heavy metals, and sediment discharged from waste areas and interact with ecosystems is present. Runoff and leakage from tailings and waste rock can pollute streams flowing out of the mining area, causing widespread damage downstream. This has a direct affect on communities and people who depend directly on goods and services provided by ecosystems, and the quality of, and their access to, natural resources.
Hyperaccumulator plants were defined as those that accumulate metal to concentrations that are 10 –100 times the concentrations found in plants called “normal”. These concentrations are an order of magnitude higher than concentrations found in other plants that grow in the same environment.
Today, 440 hyperaccumulator plant species are known, of which 75% are nickel hyperaccumulators. The remaining plant species hyperaccumulate arsenic, cadmium, manganese, sodium, thallium and zinc.
While there exists an extensive knowledge base of hyperaccumulating plants, phytomining as a concept has received only comparatively recent attention for three reasons: (i) increased societal pressure resulting from the environmental performance of conventional mining techniques, (ii) the inability of current tecnologies to cost effectively recover metals from ores with low metal contents, and (iii) concurrent, high metal prices. phytomining requires more extensive research under field conditions on commercial scale for longer durations.
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Much research remains to be carried out, particularly in the field of increasing metal uptake by plants either by genetic manipulation or addition of specific reagents to the soil.
Further research is needed at the physiological and biochemical level for optimization of the process, greater understanding of how plants absorb, translocate and metabolize gold. Identification of genes responsible for gold uptake.
The present study aims at using phytomining technology to extract gold from ElSukari mine soil by Helianthus annuus L plant.
This was achieved by adding three solubilizing : (ammonium
Thiocyanate, ammonium thiosulphate and thiourea).
The results showed that there was an increase in the absorption of gold by some plant when phytomining was applied to induce gold absorption using Helianthus annuus L a temperatures conditions ranging from 13.6 -
29.2 ° C In Abu Rawash , Giza governorate ,and pH 7.7 of el sukari mine soil and containing 1.42 mg / kg -1 (ppm) of gold element 300 kg soil was divided into four treatments ( three of these gold solubilizing agents) by 3 kg per pot and 25 pots for each treatment Harvest intervals were 15, 30 and 60 days.
Then, the plant parts were subjected to analysis of the concentration of gold using AAS ( Flame + graphite furnace spectrometry ). In most cases, the results showed that the concentrations of gold were higher in the roots than in the rest of the plant.
The concentration of gold for treatment with ammonium thiocyanate ammonium thiosulfate and thiourea was found to be.
1. Roots: 0.01 ppm, 0.01 ppm, zero respectively at age 15 days 8.02 ppm, 2.8 ppm 4.14 ppm respectively at age 30 days.
2. Leaves: 0.006 ppm, 0.006 ppm, 01. 0 ppm respectively at age 15 days
5.77 ppm. 5.92 ppm, 3.27 ppm respectively at age 30 days.
3. 3- Stem 0.01 ppm, 0.006 ppm, 0.008 ppm respectively at age 15 days
0.3 ppm, 4.48 ppm, 2.65 ppm respectively at age 30 days.
-Age 60 days in three treatment zero.