Limestones and Dolomites

Granite and to a lesser extent granodiorite are coarse grained plutonic igneous rocks (see Rocks and Meteorites for a precise petrological definition) primarily composed of silicate minerals such as quartz and feldspars often with small amount of accessory minerals such as 

Construction materials Density (/Vkg.m ) Young s Compressive Modulus of modulus strength rupture ( /GPa) (o-yMPa) (Mofi/MPa) Thermal conductivity (k/W.m. K ) Specific heat capacity (cyj.kg. K ) Linear thermal expansion coeff. (a,/10 K ) 

Sauterey, R.(eds.)(1982) Le hewn hydraulique. Presses de I ficole Nationale des Fonts et Chaussdes (ENPC), Paris. 

BOYTON, R.S. Chemistry and Technology of limestone, 2nd. ed. Wiley Interscience, New York. 

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Alaska, Washington, and Nevada. Ores of the Southeast Missouri lead belt and extensive deposits such as in Silesia and Morocco are of the replacement type. These deposits formed when an aqueous solution of the minerals, under the influence of changing temperature and pressure, deposited the sulfides in susceptible sedimentary rock, usually limestone and dolomites. These ore bodies usually contain galena, sphalerite, and pyrite minerals, but seldom contain gold, silver, copper, antimony, or bismuth. 

Table 7 presents 1991 statistics on limestone and dolomite uses, and includes production from 2338 U.S. plants (16). Generally the growth markets ... 

Table 7. Crushed Limestone and Dolomite Sold or Used by Producers in the United States, 1991 ...

Filter Beds. The sprinkling filter beds of sewage plants are composed of closely screened mineral aggregate of 38—64 mm or 51—76 mm that meet a severe soundness test. Much of this requirement is suppHed by dense, fine-grained, hard limestone and dolomite. 

Sulfur dioxide emissions may affect building stone and ferrous and nonferrous metals. Sulfurous acid, formed from the reaction of sulfur dioxide with moisture, accelerates the corrosion of iron, steel, and zinc. Sulfur oxides react with copper to produce the green patina of copper sulfate on the surface of the copper. Acids in the form of gases, aerosols, or precipitation may chemically erode building materials such as marble, limestone, and dolomite. Of particular concern is the chemical erosion of historical monuments and works of art. Sulfurous and sulfuric acids formed from sulfur dioxide and sulfur trioxide when they react with moisture may also damage paper and leather. 

Lime is among a family of chemicals which are alkaline in nature and contain principally calcium, oxygen and, in some cases, magnesium. In this grouping are included quicklime, dolomitic lime, hydrated lime, dolomitic hydrated lime, limestone, and dolomite. The most commonly used additives are quicklime and hydrated lime, but the dolomitic counterparts of these chemicals (i.e., the high-magnesium forms) are also widely used in wastewater treatment and are generally similar in physical requirements. 

The typical value of porosity for a clean, consolidated, and reasonably uniform sand is 20%. The carbonate rocks (limestone and dolomite) normally exhibit lower values, e.g., 6-8%. These are approximate values and do not fit all situations. The principal factors that complicate intergranular porosity magnitudes are uniformity of grain size, degree of cementation, packing of the grains, and particle shape. 

Select a tungsten carbide insert bit with a medium offset and long chisel crested inserts when drilling sandy shale with limestone and dolomite. Use bits type 4-1 to 5-3. 

Select a tungsten carbide bit with medium or no offset and chisel crested inserts when drilling sandy shales, limestones and dolomites. Use bit type 5-3 or 6-4. 

Equation 4-207 is used in carbonates (limestone and dolomite) and Equation 4-208 is used in unconsolidated to medium consolidated sandstones. A third Equation 4-209 can be used in highly consolidated sandstones. This is... 

The principal minerals of Sr are strontionitc (SrCO,) and celesite (SrS04) those of Ba are barite (BaS04) and witherite (BaCO,). Strontionitc and barite are the usual sources of metallic Sr and Ba, respectively. Traces of both elements occur in nearly all limestones and dolomites and small amounts are usually present in natural limes. Furthermore, although neither element occurs as an independent silicate, traces of each may replace part of the Ca, Pb or K in compounds containing one or more of these elements. 

Carbonates (limestone and dolomite) will dissolve in and neutralize acidic wastes with the following process ... 

Sedimentary rocks that are most likely to meet the first three criteria are unfractured shale, clay, siltstone, anhydrite, gypsum, and salt formations. Massive limestones and dolomites (i.e., carbonates with no continuous fracturing and solution channels) can also serve as confining layers. Then-suitability must be determined on a case by case basis. The fourth criterion has no relationship to lithology. 

Marble. The word marble is used as the common name for two types of monomineral rocks one derived from limestone and therefore composed of calcium carbonate, the other derived from dolomite and composed of calcium magnesium carbonate. Extremely high pressures and heat during past geological times modified the structure of both limestone and dolomite, compacting them into a characteristic crystal structure. Most marble is white however, minor and trace amounts of metallic impurities cause the formation of stains in a variety of colors, hues, and patterns, or of colored marble. 

It has been shown that the development of wormholes in carbonate rocks is a consequence of diffusion-limited (mass-transfer-limited) kinetics of attack (6). Such kinetics prevail in most of these rocks, i.e. limestones and dolomites, providing that, for the latter, the temperature is larger than about 200°F (90°C) (7-8). 

For WGS, commercial catalysts are only operated up to 550 °C and no catalysts are available for higher temperatures, because adverse equilibrium conversion makes the process impractical in the absence of a CO2 sorbent. Han and Harrison [38] have shown that, at 550 °C, dolomite and limestone have a sufficiently high WGS activity. For SMR a conventional Ni SMR catalyst is used in a 1 1 ratio with CaO [30]. Meyer et al. [32] have also used a Ni-based catalyst in combination with limestone and dolomite, and achieved CH4 conversions of 95% at 675 °C while the CH4 conversion at equilibrium was 75%. 

A general problem with CaO, limestone and dolomite is the limited lifetime of the C02 acceptor material [32], The capacity for C02 is initially very high, but is depleted to almost zero after several cycles. Although the minerals are relatively cheap, this would imply a very considerable stream of waste material coming out of the hydrogen plant. Novel materials are in development with a higher stability [39]. 

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