Synthesis of magnesian calcite at low temperatures and pressures

Abstract

Abstract-As

Magnesian calcite synthesis from calcium bicarbonate solution containing magnesium and barium ions.

“…And a number of studies have been carried out on the measurement of the distribu tion coefficients of trace metals between solu tion and carbonate precipitate; Sr (HOLLAND et al, 1963(HOLLAND et al, , 1964B ODINE et al, 1965;KINSMAN and HOLLAND, 1969;, KATZ et al, 1972, Zn (TSUSUE and HOLLAND, 1966;CROCKET and WINCHESTER, 1966;KITANO et al, 1968), Cu (KITANO et al, 1968), U02 , Mn (BODINE et al, 1965;RAISWELL and BRIMBLECOMBE, 1977), Ba , Mg (KITANO and KANA MORI) 1966;KATZ, 1973;KITANO et al, 1976), Cd (KITANO et al, 1978). Magnesium carbonate in skeletal calcite is present as a solid solution between calcite and magnesite or dolomite (CRAVE, 1952;GOLDSMITH et al, 1955;KITANO and FURUTSU, 1959;KITANO and KANAMORI, 1966). And magnesian calcite and aragonite are unstable, relative to Mg-poor calcite at ordinary temperature and pressure (GARRELS et al, 1960;CHAVE et al, 1962;JANSEN and KITANO, 1963;PLUMMER and MACKENZIE, 1974;DE BOER, 1977).…”

“…The skeletal parts of calcareous marine organisms are composed of the minerals, calcite, aragonite and magnesian calcite (CHAVE, 1952(CHAVE, , 1954LOWENSTAM, 1954;KITANO and KANAMORI, 1966;KITANO et al, 1969). The study on the distribution of trace metals for these minerals is important for the understanding of the geo chemical behaviors of trace metals on the earth's surface.…”

“…Laboratory syntheses of magnesian calcite were accomplished at high temperatures and pressures (HARKER and TUTTLE, 1955;GRAF and GOLDSMITH, 1956;GOLDSMITH and HEARD , 1961), and recently at normal temperature and pressure from aqueous solutions (KITANO and KANAMORI, 1966;GLOVER and SIPPLE, 1966;KITANO et al, 1976;OHDE and KITANO, 1978).…”

Incorporation of fluoride ions into calcite. Effect of organic materials and magnesium ions in a parent solution.

“…The presence of magnesium ions in a parent solution favors aragonite formation, and that of certain organic materials favors calcite forma tion (KITANO and HoOD, 1965 Magnesium carbonate in resulting calcites was confirmed to be contained as a form of a solid solution, (Ca, Mg)C03 (KITANO and KANAMORI, 1966).…”

“…The parent solutions were vigorously stirred with magnetic stirrer (stirring system) or allowed to stand with occasional agitation (non-stirring system) at 250C, until about 50% of calcium ions were precipitated as calcium carbonate. The experi ment on the effect of magnesium ions on the fluoride incorporation was carried out in both stirring and non-stirring systems, because stirring of a parent solution has a significant influence on magnesium carbonate content of formed calcite (KITANO and KANAMORI, 1966;KITANO et al, 1976). And the other experiments were done only in the non-stirring system.…”