What is Phytomining?
Phytomining has been practiced by humans for thousands of years, but it has only recently become possible to scale up the process to industrial levels. The basic idea behind phytomining is that it’s easier and cheaper to extract metals from plants than it is from ores or other sources of raw material.
Phytomining is the process of recovering metals from phytoextracting crops. It is a form of mining that uses plants as bioaccumulation tools to extract desired metals from soil, water, or tailings. Phytomining uses plants to extract and accumulate desired metals within their biomass. Plants are grown in soil or another medium amended with mineralized metal salts (root feed). The roots take up the minerals, which are broken down into smaller ionic forms that can be taken up by other root cells. Crop residues are left behind to protect the soil from erosion and reduce leaching of accumulated metals. Soil amendments with high concentrations of desired minerals are created so that future plantings will be successful. Phytomining includes all activities from initial site testing and analysis, through engineering, construction, commissioning, and ongoing monitoring to ensure optimal performance during the operational phase .
Why Use Phyto-mining?
There are numerous reasons to employ phytomining. First, the process is relatively inexpensive and can be deployed in areas or with materials (e.g., radioactive soils) that would otherwise be inaccessible or uneconomical to mine. Second, it does not involve excessive energy consumption or produce large quantities of greenhouse gases. Third, it does not cause collateral damage to ecosystems as does conventional mining. Fourth, it can be used to remediate soils contaminated with heavy metals and radionuclides. Fifth, it can be applied to agricultural sites to increase the yield of desired metals in the edible or commercial parts of the crops. Other benefits include the ability to use various crops, which provides a way to control pests and diseases without the use of chemicals. Additionally, phytomining can be used in conjunction with other methods, such as bioleaching. It also acts as a carbon sink and can help to reduce agricultural runoff of contaminants.
Dr Moren has since gone on to develop several other types of phyto-metals and has also worked with other metal-rich crops such as barley and wheat.
Advantages of Phyto-Mining
The advantages of phytomining relative to conventional mining include less contamination of the environment, the potential for higher tonnage, fewer impurities, lower energy consumption, and less need for mining-related infrastructure. However, it entails a different set of risks, such as the potential for leaching of accumulated metals.
Metals can be found within living organisms, in their skeletons and in their tissues. In most cases, metals are not in such high concentrations as they would be if they were mined from ores or other sources of raw materials. To achieve higher concentrations, plant matter must be crushed or pulverized before extraction occurs.
Phytomining is the production of a `crop’ of a metal by growing high-biomass plants that accumulate high metal concentrations. This is achieved by using plant species with high metal concentrations and selecting for more metal in the biomass. Phytomining has been extensively used to produce rare metals from waste materials such as lead batteries and steel dust, but it has also been used to extract metals from agricultural products such as plants (phytoextraction).
In this paper, we have evaluated several plants for phytoextraction of cadmium and lead from soils contaminated with cadmium and lead using a modified version of the standard phytostabilization protocol (PS) developed by Heinrich (2006) for phytostabilization of soils contaminated with heavy metals. The standard PS was modified by adding a pH adjustment step prior to incubation in order to adjust pH towards neutral values (>pH 7). The results showed that some plants were able to reduce concentrations of both metals significantly, while others showed no significant reduction at all.
The Limitations of Phyto-Mining
Almost all metals are toxic at high concentrations. Therefore, growing plants with high concentrations of metals in the same soil where food crops are grown poses a potential health risk. In practice, however, the accumulation of metals in edible parts of the plant is usually significantly less than in the soil. Phytomining may cause environmental damage if wild-growing vegetation is contaminated with excessive amounts of metals, soil amendments with high concentrations of metals are left on the soil surface, or irrigation water with high concentrations of metals is used.
The term “phyto-mining” describes the growing of plants for the purpose of extracting metals from them. This process can be done indoors or outdoors, depending on where the plant is grown.
Types of Phyto-Mining
Phytomining is a general term that refers to the extraction of metals from soils by growing plants. There are two types of phytomining: Extraction of metals from soil by growing plants: general definition for the use of plants for the extraction of metals from contaminated soil Extraction of metals from soil by growing plants: general definition for the use of plants for the extraction of metals from contaminated soil Extraction of metals from soil by growing plants: specific definition for the use of plants for the extraction of copper and other base metals from soil – Extraction of metals from soil by growing plants: Specific definition for the use of plants for the extraction of uranium from soil.
A number of plants are used for phyto-mining, including cassava, sweet potatoes, beans and peppers. However, the focus of this article will be on the use of cassava as a source of cobalt.
Cobalt is an essential trace element that is also found in many other foods, such as wheat germ and soybeans. Cobalt deficiency can cause rickets in children and osteoporosis in adults. In addition to its role as an essential element for human health, cobalt is also an important component in stainless steel production, catalytic converters used in automobiles, and batteries used in hybrid cars and electric vehicles, among other applications. Cobalt is also a required nutrient for certain insects such as bees and wasps, which pollinate crops such as tomatoes and cottonseed oilseed crops (such as soybeans).
The demand for cobalt has increased due to its use in batteries for hybrid cars and electric vehicle technology. However, much of the current demand comes from China, where one-third of all new cars sold have been equipped with rechargeable lithium ion batteries made with cobalt compounds.
Summing up
Phytomining is a form of mining that uses plants as bioaccumulation tools to extract desired metals from soil, water, or tailings. Phytomining uses plants to extract and accumulate desired metals within their biomass. Plants are grown in soil or another medium amended with mineralized metal salts (root feed). The roots take up the minerals, which are broken down into smaller ionic forms that can be taken up by other root cells.
Crop residues are left behind to protect the soil from erosion and reduce leaching of accumulated metals. Soil amendments with high concentrations of desired minerals are created so that future plantings will be successful. Phytomining includes all activities from initial site testing and analysis, engineering, construction, commissioning, and ongoing monitoring to ensure optimal performance during the operational phase.
Phyto mining can be used to extract metals from plant residues, which are usually discarded as waste in industrial processes. Phytomining is a promising alternative to industrial mining operations, because it allows for the extraction of metals from low-value sources (such as biomass). Phytomining also has environmental benefits over conventional mining practices, as it uses less energy and water than traditional methods.
