Talc: The Mineral

AP Enviromental Science

Chemical Formula, Physical & Chemical Properties of Talc

Chemical Formula: Mg3Si4O10(OH)2 Physical Properties: Talc is usually green, white, gray, brown or colorless. It is a translucent mineral with a pearly luster. It is the softest known mineral and is assigned a hardness of 1 on the Mohs Hardness Scale. Chemical Properties: Talc is a mineral that is most often found in the metamorphic rocks of convergent plate boundaries. It forms from at least two processes. Most large talc deposits in the United States formed when heated waters carrying dissolved magnesium and silica reacted with dolomitic marbles. A second process of talc formation occurred when heat and chemically active fluids altered rocks such as dunite and serpentinite into talc.

Talc's Acquisition: Where is Talc Produced? How is it mined?

In 2011 talc production was still down in response to the world-wide economic downturn. For most countries 2011 production was about the same as production in 2010. China, South Korea, India, United States, Finland, Brazil, France and Japan are the leading producers. The United States is self-sufficient for most types of talc used in manufacturing. Estimated 2011 production was 615,000 metric tons with a value of about $20 million. Three companies in the United States account for nearly 100% of the country's production. Most talc in the United States is produced from an open pit mine where the rock is drilled, blasted and partially crushed in the mining operation. The highest grade ores are produced by selective mining and sorting operations.
Great care is taken during the mining process to avoid contaminating the talc with other rock materials. These other materials can have an adverse effect on the color of the product. Contamination can introduce hard particles that cause problems in applications where talc is being used because of its softness or lubricating properties. Partially crushed rock is taken from the mine to a mill where it is further reduced in particle size. Impurities are sometimes removed by froth flotation or mechanical processing. The mills produce crushed or finely-ground talc that meets customer requirements for particle size, brightness, composition and other properties.

The Processing of Talc: From Raw to the Marketplace

How is talc manufactured?

Drilling of the holes is done for the implantation of the explosives. Then comes the step in which the explosives are planted. After the occurrence of the blast, the available talc rocks are excavated for the commercial development. Thereafter, the transportation of the talc rocks is conducted is the safest and secured manner. The stock of the raw talc rocks are delivered in the warehouse in the batches for the further process. In order to accomplish the purification process in the most precise manner, the proper assessment of the chemical composition is conducted. The process of floatation takes place for the elimination of all the impurities and unwanted particles associated with the natural talc rock. Thereafter purification is executed by keeping in mind certain parameters and all the end products are ensured according to them. The slurry of talc is received as one of the primary end products. The slurry is dried with the help of pressure filters and the intermediate product of the whole manufacturing process is received in the form of filtered cake. The advanced milling technology is put into use in order to receive the finely powdered talc. The large size paper bags are put into use in order to properly accumulate the finally produced talc.

Product Made of Talc: Baby Powder

Baby powder is an astringent powder used for preventing diaper rash, as a deodorant, and for other cosmetic uses. It may be composed of talc (in which case it is also called talcum powder) or corn starch. Talcum powder is harmful if inhaled since it may cause aspiration pneumonia or granuloma. Baby powder with Talc costs around 4-10 bucks.

The Present and Past Uses of Talc

"Most people are familiar with the mineral talc. It can be crushed into a white powder that is widely known as "talcum powder". This powder has the ability to absorb moisture, absorb oils, absorb odor, serve as a lubricant and produce an astringent effect with human skin. These properties make talcum powder an important ingredient in many baby powders, foot powders, first aid powders and a variety of cosmetics. "

"A form of talc known as "soapstone" is also widely known. This soft rock is easily carved and has been used to make ornamental and practical objects for thousands of years. It has been used to make sculptures, bowls, countertops, sinks, hearths, pipe bowls and many other objects."

"Although talcum powder and soapstone are two of the more visible uses of talc they account for a very small fraction of talc consumption. Its hidden uses are far more common. Talc's unique properties make it an important ingredient for making ceramics, paint, paper, roofing materials, plastics, rubber, insecticides and many other products."

Source:

http://www.minerals.net/mineral/talc.aspx

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Enviromental Impacts of Talc Mining

"All mining activities have an impact on the environment: quarrying, driving adits, sinking shafts, creating open pits, mounding of overburden rock, tailings and settlement ponds, grinding rock, operating and maintaining mining machinery and transporting ore and finished products. European talc producers consider that honouring their environmental responsibilities is not only good business practice; it is the right thing to do..The approach is not just to minimise adverse impacts but to create positive improvements to the environment where practical.

This extends to the operations of EUROTALC members outside Europe.

Talc Mining and processing

To ensure environmental protection offsets the adverse effects of mining and processing, EUROTALC member companies operate environmental management systems in line with international standards such as the ISO 14000 series. Most members’ operations are certified to this standard. Internal and external auditing systems are implemented to monitor the management systems, compliance with official regulations, and conformity to company policies and standards.

Environmental care focuses mainly on the following 5 areas:

Integration of mining and processing facilities into their natural environment

When planning, building and opening new mines and/or processing facilities, care is taken to mitigate the visual impact of mining and processing operations. This planning also includes rehabilitation/restoration of the environment and its biodiversity during mining and when an operation is closed.

Emission control

Mining activities, ore processing (crushing, grinding, flotation) and product storage, bagging and shipping inevitably generate emissions in the form of dust, noise and waste water—although the latter is very limited as talc processing is mostly carried out dry. In order to reduce the effect on the environment and to safeguard the health of employees, environmental and occupational health and safety programmes are implemented. The procedures monitor emissions on a regular or continuous basis and corrective measures are taken when appropriate. Programmes are implemented in order to reduce emissions at source.

Waste management

Talc mining and processing generate various waste materials: packaging, consumables, and waste rock. Waste materials are sorted and recycled in line with prevailing waste management programmes. Rock which has to be disturbed in order to access the talc is used on site for landscaping, land restoration and creating safety barriers for mobile equipment in the mine.

Water and energy conservation

Waste and process waters are treated and recycled to the maximum practical extent.

As energy costs are high and as creating energy produces greenhouse gas (GHC) emissions causing climate change, all ways to recycle, recover or reduce energy use in the processes or to promote other uses are studied and implemented where practical.

Hazardous products and waste management. All consumable products can have an impact on the environment. Hydrocarbons and chemical reagents, for example, are governed by specific procedures for ordering, storage, handling and final treatment or disposal. The use of hazardous chemicals in the making of talc products is, however, very small, as can be seen by the data in the European Union Sustainable Development Indicators Voluntary Reporting Scheme for the Non-Energy Extractive Industry."

Source: http://www.eurotalc.eu/environmentalimpact.html

Lynn Lague, Ms. Miller, APES 4th Block, 11/8/14