Limestone As An Industrial Mineral

Limestone as an Industrial Mineral Kwaku Boakye Mineral Engineering Department and Bureau of Geology New Mexico Institute of Mining and Technology February 9, 2007

Ou tlin e       

Introduction Geologic description Distribution Production Processing Marketing Uses

Introductio n  Limestone and dolomite constitute a group of raw material commonly referred to as carbonate rock  In 2002, ~1.6 billion tons were produced in the United States (Freas et al, 2006).  71% of all stone quarried mined in the United State is carbonate rock

Ge ologic d escriptio n  Origin of limestone Limestones of economic importance are biologically derived from seawater and originally deposited in relatively shallow marine environments Environment of deposition and the organic community largely determine the geometry of a carbonate deposit Environment of deposition is significant to the industrial minerals geologist because it determines the size, shape, and purity of the deposit High-energy zones produce relatively pure limestones because clay impurities are removed by high currents

 Mineralogy Limestone are sedimentary rocks Chemical Composition of CaCO3 Similar in chemical composition as aragonite but different crystal structure Aragonite is metastable and alters to calcite in time Siderite (FeCO3), Ankerite (Ca2MgFe(CO3)4) and Magnesite (MgCO3) are commonly found associated with limestone’s and dolomites

http://www.fi.edu/fellows/fellow1/oct98/expert/limestone.htm

Limestone Sandstone

http://en.wikipedia.org/wiki/Image:Limestoneshale7342.jpg

 Chemical Properties Chemical and Physical attributes are independent properties Pure calcite in the form of poorly cemented chalk is not only unique in its low strength but also high absorption Pure calcitic marble of the same chemical composition as chalk is relatively strong, unabsorptive, and unreactive Chemical analysis is of upmost importance in stone used for chemical purpose, such as glass raw material, flux, or cement

Chemical properties are not so relevant for aggregates products Chemical analysis are made to determine impurities Impurities related with lime stone includes clay minerals, resistance minerals such as quartz, and organic material. Most test are performed in accredited Laboratories Many state surveys have files of chemical data obtained from quarry sampling and coring programs

 Terminology used describe the purity of carbonates High-calcium limestone:

greater than 95% CaCO3

High-magnesium dolomite:

greater than 42% MgCO3

High-purity carbonate:

greater than 95% combined CaCO3 and MgCO3

http://books.smenet.org/Surf_Min_2ndEd/sm-ch02-sc10-ss11-tbl001.cfm

 Physical Properties Carbonates are similar in physical properties making it difficult to distinguish Specific gravity, color, crystal form, hardness, etc are some of the physical properties This properties are tested using testing procedures in ASTM and AASHO

Physical Properties of Calcite, Dolomite, and Aragonite. Mineral

Chemical Composition

Physical Properties

Calcite

CaCO3

Hexagonal crystal system, commonly good rhombohedral cleavage. Mohs’ hardness, 3. Specific gravity, 2.72. Commonly colorless or white but may be other colors because of impurities.

Dolomite

CaMg(CO3)2

Hexagonal crystal system, commonly good rhombohedral crystals with curved faces. Mohs’ hardness, 3.5 to 4. Specific gravity, 2.87, but common impurities such as iron can raise it to 2.95 or higher. Commonly white or pink.

Aragonite

CaCO3

Orthorhombic crystal system. Mohs’ hardness, 3.5 to 4. Specific gravity, 2.93B2.95. Commonly colorless, white, or yellow but may be other colors because of impurities.

http://books.smenet.org/Surf_Min_2ndEd/sm-ch02-sc10-ss11-tbl001.cfm

Limestone pot hole

http://en.wikipedia.org/wiki/Limestone#Limestone_landscape

Di str ibution Carbonate rocks are deposited from Precambrian to Holocene time (Parker, 1967) Carbonate rock compose only about 0.25% of the volume of the earth crust (Parker, 1967) Carbonate comprise of 15% of the worlds sedimentary rocks Each carbonate deposit differ in their geologic characteristics Highly-purity carbonate rock deposits are not overly abundant Hawaii, Louisiana, Mississippi, New Hampshire and Rhode Island and all of Canadian Province are in abundance of pure limestone

Pr oductio n Exploration Coring Rock Bitting Surface Sampling 

Mining Open Pit Underground 

Pr ocessing  Processing varies with the end use of the product and targeted consuming industries  Site for processing depends on Type of Mine Haulage Distance Surface Topography  Processing involves Sawing Crushing Screening

Ma rketing  Marking is influence by specification requirements  Specification differ from companies to companies even though they may produce the same product  Market price depends on the supplier ability to price the product on its value to customer but not the base on cost of production  Adding value involves strong commitment to research, development and corporate support from start of mining and followed by technical support

Uses  the manufacture of quicklime (calcium oxide) and slaked lime (calcium hydroxide)  cement and mortar  pulverized limestone is used as a soil conditioner to neutralize acid soil conditions  crushed for use as aggregate - the solid base for many roads  geological formations of limestone are among the best petroleum reservoirs  as a reagent in desulfurizations  glass making  toothpaste

Concl usi on  Limestone and dolomite have been and continue to be one of the most important raw materials in the United States and the world  Limestone is a carbonate and sedimentary rock

 Limestone of economic importance are biologically derived form seawater and accumulated in relatively shallow marine environment.  Market price depends on the supplier ability to price the product on its value to customer but not the base on cost of production

 Demand of limestone and dolomite is expected to grow at an average annual rate of about 2.0% to 2.5%  In 2002, about 1.6 billion tone were produced in the United States (Freas et al, 200).

Ref erence

 http://en.wikipedia.org/wiki/Image:Limestoneshale7 February 8th 2007  file:///I:/SME--ONLINE%20DIGITAL%20LIBRARY% February 8th 2007  http://www.fi.edu/fellows/fellow1/oct98/expert/limes February 8th 2007  Kogel, E. J., Trivedi, C. N., Barker, M. J., and Krukowski, T. S., 2006, Industrial Minerals and Rock: Society for Mining, Metallurgy and Exploration, v.1, p. 581-597, ISBN: 0-87335233-5/978-0-87335-233-8