Mineral crystal

The matte can be treated in different ways, depending on the copper content and on the desired product. In some cases, the copper content of the Bessemer matte is low enough to allow the material to be cast directly into sulfide anodes for electrolytic refining. Usually it is necessary first to separate the nickel and copper sulfides. The copper—nickel matte is cooled slowly for ca 4 d to faciUtate grain growth of mineral crystals of copper sulfide, nickel—sulfide, and a nickel—copper alloy. This matte is pulverized, the nickel and copper sulfides isolated by flotation, and the alloy extracted magnetically and refined electrolyticaHy. The nickel sulfide is cast into anodes for electrolysis or, more commonly, is roasted to nickel oxide and further reduced to metal for refining by electrolysis or by the carbonyl method. Alternatively, the nickel sulfide may be roasted to provide a nickel oxide sinter that is suitable for direct use by the steel industry. 

The release of ions through weathering is also considered an input to soils. Elements that were bound in mineral crystals are released into the soil solution. These ions can be involved in soil processes and the formation of new organic or inorganic materials, or leached from the soil into the groundwater. 

Very fine-grained sulfides (n x 10 xm), which are common in Kuroko ores (Shikazono, unpublished), have not been reported from midoceanic ridge chimneys. However, SEM (scanning electron microscope) observations of Kuroko and Mariana chimneys indicate that the minerals are aggregates of very fine-grained crystals. Therefore, SEM observation is necessary to measure grain size of individual mineral crystals. However, data from SEM observations of midoceanic ridge chimneys are scarce. 

In clay mineral crystals, atoms having different valences commonly will be positioned within the sheets of the structure to create a negative potential at the crystal surface. In that case, a cation is adsorbed on the surface. These adsorbed cations are called exchangeable cations because they may chemically trade places with other cations when the clay crystal is suspended in water. In addition, ions may also be adsorbed on the clay crystal edges and exchange with other ions in the water. 

The purpose of employing various light incidents when using a microscope was to distinguish between different crystals such as mineral crystals (e.g., clays, silicons, NaOH, etc.) from surfactant crystals (30-33). It was found that under transmittant light only bituminous hydrocarbons were non-transparent (absorb light) and appeared either... 

Whenever it is possible to analyze in a given rock at least two minerals that crystallized at the same initial time t = 0, equation 11.86 can be solved in t. On a Cartesian diagram with coordinates Sr/ Sr and Rb/ Sr, equation 11.86 appears as a straight line ( isochron ) with slope exp(At) — 1 and intercept ( Sr/ Sr)o. As shown in figure 11.14A, all minerals crystallized at the same t from the same initial system of composition ( Sr/ Sr)o rest on the same isochron, whose slope exp(At) — 1 increases progressively with t. 

Typical marine water contents of Br are 65 ppm. The first chloride salt precipitated in an evaporite basin is halite (70-75 ppm Br). Bromine content of halite increases to >230 ppm Br as the first potassium mineral crystallizes (Valyashko 1956). 

Once formed, crystals can interact with or adhere to other components. Adhesion can occur directly between crystals to form larger structures which may act as the nidus for further mineralization. Crystals can also interact with metabolites and/or tissues to form such structures. These interactions can and do alter the stereochemical course of crystal assembly, and molecular recognition probably accounts for the striations and intricate geometries adopted by biomineralized structures. The role and composition of metabolites comprising the matrix may be useful to understanding the local and large-scale structure of biominerals. 

Copper-nickel matte obtained in this stage is allowed to cool slowly over a few days to separate mineral crystals of copper sulfide, nickel sulfide and nickel-copper alloy. The cool matte is pulverized to isolate sulfides of nickel and copper by froth flotation. Nickel-copper alloy is extracted by magnetic separation. Nickel metal is obtained from the nickel sulfide by electrolysis using crude nickel sulfide cast into anodes and nickel-plated stainless steel cathodes. 

Theophrastos (372-287 BC), the author of the oldest book on minerals. On Stones, referred briefly to regular polyhedral forms exhibited by mineral crystals [1 ]. In later books on minerals, polyhedral forms bounded by mirror-flat faces are mentioned. 

In natural crystals, whose growth processes cannot be directly observed, the difference in R is recorded as the difference in separation in growth banding (see Chapter 6). Based on these observations, several papers were reported in which the direction of flow of ore-forming fluid was evaluated in pegmatite and hydrothermal veins. In many cases in which the natural mineral crystals exhibited extensively malformed Habitus from that predicted by the structural form, the malformation could be considered to be due to the remarkable anisotropy involved in the environmental conditions, such as the directional flow of the solution, which is similar to the situation of growth of NaCl from solution in between two glass plates, as discussed above. 

Many investigations have been carried out since the seventeenth century that analyze the Tracht variations of growth forms. These investigations fall into two principal categories (i) experiments designed to observe Tracht variations in relation to growth conditions, and (ii) the analysis of Tracht variation of mineral crystals with respect to the geological environment in which they occur. 

The earliest interest in surface microtopographs observable on crystal faces developed in the 1920s these observations were made using reflection-type microscopes on etch figures seen in natural mineral crystals [1], [2]. At that time. 

In regional metamorphic rocks and contact metamorphic (metasomatic) rocks, new mineral crystals grow in solid rocks in which there was a change in conditions. However, the process is not the same as straightforward solid state growth or recrystallization. Since volatile components such as H O and CO, which were originally present in the rock, are involved, it is better to assume a... 

P5Trite and calcite are mineral crystals that represent a wide Habitus and Tracht variation. Pyrite is the most persistent mineral among sulfide minerals, occurring in a wide range of modes, including inorganic processes and bacterial action, and it can also be synthesized by hydrothermal or chemical vapor transport methods. 

As summarized in Table 14.1, teeth, bones, shells, etc. are indispensable components, consisting of inorganic mineral crystals and protein film, with sizes, morphologies, and textures suitable to fulfil the function of the particular organs involved. In this section we will look at hydroxyapatite, aragonite and calcite (two polymorphs of CaCO ), and magnetite in greater detail. 

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