Dolomite dolomitization

Source Dolomite Dolomite Dolomite Dolomite Limestone... 

To prepare the initial system, we use the analysis in Table 25.1 for the saline water, which we assume to be in equilibrium with potassium feldspar, quartz, muscovite, and dolomite ( dolomite-ord is the most stable variety in the database). The commands... 

Dolomite Dolomite is one of the most abundant sedimentary carbonate minerals, yet after years of intense study its mode of formation remains controversial, and its properties under Earth surface conditions are less well known than for most other carbonate minerals. The primary reason for this seems to be that its formation is kinetically hindered by its complex and well-ordered structure. Another problem in understanding dolomite may be as Lynton Land says "there are dolomites and dolomites and dolomites". The topic of dolomite genesis will be dealt with in several later sections of this book. 

Figure 8.25. Some chemical and diagenetic properties of organic-rich marine sediments as a function of depth based on DSDP interstitial water profiles. A. Schematic gradients of SO42-, total alkalinity, Ca2+ and Mg2+ in pore waters, and zones of sulfate reduction, methanogenesis and fermentation. Magnesium diffuses into the sediment and organogenic dolomite forms at depth. B. Logarithm of calculated saturation states of interstitial waters with respect to dolomite. Dolomite saturation=0. All these pore waters are oversaturated with respect to dolomite. (After Compton, 1988.)...

In the presence of both calcite and dolomite, dolomite dissolves while calcite precipitates (Table 42, Fig. 50), because the solubility product of CaC03 is exceeded. This process is called incongment dissolution (see chapter 1.1.4.1.3). The maximum of dissolution/ precipitation shifts to lower temperatures (6°-7°C). 

ABSTRACT As a step in the application of the cracking of tar in fuel gas amelioration the characteristics of the endothermic reaction potential of tar was studied experimentally and theoretically. In this context, however, due to the structural complexity of tar and/or tany constituents in fuel gas well defined hydrocarbons as tar model compounds were applied with inexpensive and readily available materials (dolomites, dolomitic magnesium oxide [MgO], quicklime [CaO]). The effects of operation condition on extent of hydrocarbon conversion, gas product composition, and corresponding endotherai of the reaction potential have been explored. The results obtained in this work provide a basis for ture considerations of catalytic tar cracking. 

Rock type limestone limestone limestone dolomite dolomite limestone limestone St limestone dolomite 7 ... 

Dolomitisation results in the formation of the double carbonate CaC03 MgCOa- It may be produced near the surface, soon after the deposit has formed, or in the burial stage at a much later date. Most ancient limestones, formed in the Precambrian era are predominantly dolomitic. Dolomites typically contain up to 90 % of the double carbonate, with the remainder being mainly calcite. 

Industrial applications and uses. Dead burned dolomite exhibits high refractoriness and can withstand temperatures up to 2300 C. It is widely used as a refractory material wherever steel is refined using basic slag. It is used for original hearth installations in open hearth furnaces as well as for hearth maintenance. These hearths are installed using tar-dolomite ramming mixes and rammed dolomite. Dolomite refractories are also used in electrical furnaces and in the cement industry during cHnker manufacture. 

Dolomite—Dolomite consists of carbonate mineral known as magnesium limestone (CaMg(C03)2) and occurs in more or less the same settings as limestone. Dolomite is formed when some of the calcium in limestone is replaced by magnesium. 

During natural deposition of carbonates, when magnesium salts are present, a mixture of magnesium and calcium carbonates are precipitated, which is known as dolomite. Dolomite contains about 40 to 45 % MgCOj and 55 to 60 % CaCOg. Its properties are close to those of natural calcium carbonate, except that it is slightly denser and less bright and less sensitive to acid than calcium carbonate. 

Dolomite composed of more than 50% carbonates, of which more than half is dolomite. Dolomite can precipitate directly from a solution containing Mg, Ca, and carbonate ions or by chemical alteration of limestone or calcareous mud (dolomitization). Dolomite frequently forms larger crystals than the calcite it replaces (Al-Awadi et al., 2009) and forms good reservoir properties. 

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