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Water magnesian

Thus, larger solid/water ratios such as are encountered in pore waters of sediments lead to smaller MgC(>3 contents in the equilibrium magnesian calcites although in either case the magnesium content of the solid increases. Wollast and Reinhard-Derie presented data to support the theory from the standpoint of dissolution and some of our results for the precipitation case... [Pg.646]

Fig. 2. 15 Schematic representation of the magnesian-vermiculite structure. (A) The structure projected on (010) showing the layering of T and O sheets, 2 1, with the additional molecular water and ion sheet. (See Fig. 2.13 for comparison of... Fig. 2. 15 Schematic representation of the magnesian-vermiculite structure. (A) The structure projected on (010) showing the layering of T and O sheets, 2 1, with the additional molecular water and ion sheet. (See Fig. 2.13 for comparison of...
Similarly, the MgO content of the ashes is largely derived from thermal decomposition of magnesian carbonates. This process also expels water from hydrated minerals present in the oil shale. The Fe-sulphide content of the original shales is oxidized to ferric oxides and sulphates in the ash (expressed as S03 in Table 4). [Pg.268]

Two series of experiments have been conducted which elucidate the stability of pure magnesian sepiolite in aqueous solution, each using a different approach in procedure and each giving concordant and complimentary results. Wollast, et al., (1968) have used sea water as a basis for their chemical system where they have controlled the pH and SiOj content by addition of NaOH and sodium meta-silicate. This procedure incidentally changes the Na concentration of the system from that of normal sea water but this does not seem to alter the phase relations. [Pg.142]

Magnesian, limestone is calcined in an. ordinary limekiln, and Tepcatcdly washed with water to remove as musk of the lime as possible. The extent to which this is carried may be inferred from the following analyses, by Richardson, of a sample of lime in its natural state, and after it had been calcined and washed... [Pg.534]

Braude states, that the salts of magnesia are mostly soluble in water, and bitter they are all soluble in hydrochloric acid their aqueous solutions are precipitated by potassa and soda, the precipitate, being soluble In hydrochloric, nitric, and sulphuric acids, and in hydroohlorate, nitrate, and sulphate of ammonia. Ammonia only throws down part of the magnesia, and forms a double salt, and carbonates of potassa and soda only throw down part of the magnesia, except the solution be hentad, when pearly the whole is precipitated. Chloride of ammonium redissolves tiro deposit, and when previously added to the magnesian solution, no precipitate ensues on adding the alkaline carbonates, unless the liquor be warmed The bicarbonates of von. ir. [Pg.537]

If an alkaline carbonate be employed, all the earthy salts—calcareous and magnesian sulphates, chlorides, bicarbonates, and carbonates of the earths—are precipitated, while alkaline sulphates, chlorides, aod bioar-bonates which do not communicate hardness to water, aro left in solution. If carbonate of soda be employed, its reaction on sulphate of lime and chloride of magne slum will be as follows—... [Pg.1090]

Natural carbonate minerals do not form from pure solutions where the only components are water, calcium, and the carbonic acid system species. Because of the general phenomenon known as coprecipitation, at least trace amounts of all components present in the solution from which a carbonate mineral forms can be incorporated into the solid. Natural carbonates contain such coprecipitates in concentrations ranging from trace (e.g., heavy metals), to minor (e.g., Sr), to major (e.g., Mg). When the concentration of the coprecipitate reaches major (>1%) concentrations, it can significantly alter the chemical properties of the carbonate mineral, such as its solubility. The most important example of this mineral property in marine sediments is the magnesian calcites, which commonly contain in excess of 12 mole % Mg. The fact that natural carbonate minerals contain coprecipitates whose concentrations reflect the composition of the solution and conditions, such as temperature, under which their formation took place, means that there is potentially a large amount of information which can be obtained from the study of carbonate mineral composition. This type of information allied with stable isotope ratio data, which are influenced by many of the same environmental factors, has become a major area of study in carbonate geochemistry. [Pg.87]

Figure 3.1. MgC03 content of precipitated magnesian calcites as a function of the Mg to Ca molar ratio in solution. (+) Berner (1975), pH-stat experiments (a) Mucci and Morse (1983), pH-stat ( ) Kitano and Kanamori (1966), free drift ( )Glover and Sippel (1967), free drift (O) Katz (1973), free drift ( ) McCauley and Roy (1974), free drift (O) Devery and Ehlmann (1981), free drift ( )Last (1982), composition of magnesian calcites precipitating in water column, Lake Manitoba, Canada. (After Mackenzie et al., 1983.)... Figure 3.1. MgC03 content of precipitated magnesian calcites as a function of the Mg to Ca molar ratio in solution. (+) Berner (1975), pH-stat experiments (a) Mucci and Morse (1983), pH-stat ( ) Kitano and Kanamori (1966), free drift ( )Glover and Sippel (1967), free drift (O) Katz (1973), free drift ( ) McCauley and Roy (1974), free drift (O) Devery and Ehlmann (1981), free drift ( )Last (1982), composition of magnesian calcites precipitating in water column, Lake Manitoba, Canada. (After Mackenzie et al., 1983.)...
Now consider the dissolution of mineral Cao.85 Mgo.15 CO3 in pure water with one atmosphere CO2. If this mineral acted like a solid solution phase, it would dissolve congruently along reaction path AA until it reached at A saturation with a calcium-rich magnesian calcite less soluble than itself. We will see later in this... [Pg.109]

The possible presence of water in the structure of the magnesian calcite solid solution must affect its free energy of formation and thus its solubility. Inspection... [Pg.122]

In addition to calcite, aragonite and occasionally magnesian calcites may also reach the ocean floor. They may play an important role even in sediments where they do not accumulate, by contributing carbonate ion to pore waters because of their dissolution, thus causing less calcite dissolution to occur than would be the case in their absence. This process is enhanced by the benthic process of bioturbation, whereby organisms cause a physical mixing of sediments down to... [Pg.165]

Nuclear weapons testing in the atmosphere introduced excess l4C that has proven to be an excellent tracer for processes that will be important in the uptake of fossil fuel CO2. For example, Peng (1986) mapped global uptake patterns of excess 14C and used these to calculate fossil fuel CO2 uptake by the oceans. His results indicate that about 10% of the fossil fuel CO2 is "missing". In the next chapter we will discuss the possibility that this missing CO2 may be the result of dissolution of highly soluble magnesian calcites from shallow water sediments. Also, Feely and... [Pg.175]

Figure 5.9. MgCC>3 content of magnesian calcite component of shoal-water calcareous sands. A. 161 samples compiled by Garrels and Wollast (1978) B. Samples of mid-depth bank sands (Agegian and Mackenzie, 1989.)... Figure 5.9. MgCC>3 content of magnesian calcite component of shoal-water calcareous sands. A. 161 samples compiled by Garrels and Wollast (1978) B. Samples of mid-depth bank sands (Agegian and Mackenzie, 1989.)...

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Magnesian calcites water content

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