Minerals techniques

Indicator mineral techniques are one of the main exploration methods for gold and diamonds in glaciated terrain. This case study has documented indicator minerals for Ni-Cu deposits. These minerals can be used in tandem with gold and diamond indicators to assess the mineral potential of broad regions and at local scales. 

Mineralization Techniques Used in the Sample Preparation Step... 

It is clear that, extraction of organometals from sedimentary phases should be carried out with extractants which liberate organometals as much as possible without destroying them. Mineralization techniques, dissolving all or a large part of the sediment matrix should be avoided because the metal-carbon bonds of the organometal species will also be broken. The ideal extraction scenario is where ... 

A urea-mediated mineralization technique was developed to enable the formation of pHEMA-based hydrogel-calcium phosphate composites with excellent polymer-mineral interfacial adhesion strength that is desirable for bone mimics. This mineralization method was also applied to generate more sophisticated composites containing functional hydrogels that possess anionic groups mimicking the extracellular matrix proteins in bone. 

These materials have been of interest for many years because of their unusual properties. In the last decade reasonably large crystals have become available by using the mineralization technique (Spirlet and Vogt 1984), so that many different neutron inelastic experiments have been performed. Although TmSe orders with a moment of about 2(Ub (Bjerrum-Moller et al. 1977), we shall discuss the Tm compounds with the NaCl-type structure in sect. 5 in coimcction with effects of intermediate valence (IV). 

Flotation. Flotation is a gravity separation process which exploits differences in the surface properties of particles. Gas bubbles are generated in a liquid and become attached to solid particles or immiscible liquid droplets, causing the particles or droplets to rise to the surface. This is used to separate mixtures of solid-solid particles and liquid-liquid mixtures of finely divided immiscible droplets. It is an important technique in mineral processing, where it is used to separate different types of ore. 

T. J. Pinnavaia, Advanced Techniques for Clay Mineral Atuxlysis, J. J. Fripiat, ed., Elsevier, New York, 1981. 

Gadolinium is found in several other minerals, including monazite and bastnasite, both of which are commercially important. With the development of ion-exchange and solvent extraction techniques, the availability and prices of gadolinium and the other rare-earth metals have greatly improved. The metal can be prepared by the reduction of the anhydrous fluoride with metallic calcium. 

Ytterbium occurs along with other rare earths in a number of rare minerals. It is commercially recovered principally from monazite sand, which contains about 0.03%. Ion-exchange and solvent extraction techniques developed in recent years have greatly simplified the separation of the rare earths from one another. 

Two main operational variables that differentiate the flotation of finely dispersed coUoids and precipitates in water treatment from the flotation of minerals is the need for quiescent pulp conditions (low turbulence) and the need for very fine bubble sizes in the former. This is accompHshed by the use of electroflotation and dissolved air flotation instead of mechanically generated bubbles which is common in mineral flotation practice. Electroflotation is a technique where fine gas bubbles (hydrogen and oxygen) are generated in the pulp by the appHcation of electricity to electrodes. These very fine bubbles are more suited to the flotation of very fine particles encountered in water treatment. Its industrial usage is not widespread. Dissolved air flotation is similar to vacuum flotation. Air-saturated slurries are subjected to vacuum for the generation of bubbles. The process finds limited appHcation in water treatment and in paper pulp effluent purification. The need to mn it batchwise renders it less versatile. 

Mining. Underground mining procedures are used for deep fluorspar deposits, and open-pit mines are used for shallow deposits or where conditions do not support underground mining techniques (see Mineral RECOVERY AND PROCESSING). 

Microscopy (qv) plays a key role in examining trace evidence owing to the small size of the evidence and a desire to use nondestmctive testing (qv) techniques whenever possible. Polarizing light microscopy (43,44) is a method of choice for crystalline materials. Microscopy and microchemical analysis techniques (45,46) work well on small samples, are relatively nondestmctive, and are fast. Evidence such as sod, minerals, synthetic fibers, explosive debris, foodstuff, cosmetics (qv), and the like, lend themselves to this technique as do comparison microscopy, refractive index, and density comparisons with known specimens. Other microscopic procedures involving infrared, visible, and ultraviolet spectroscopy (qv) also are used to examine many types of trace evidence. 

Suface Modification Technologies II Proceedings of the 2nd International Conference on Suface Modification Techniques, Minerals, Metals, and Materials Society, Warrendale, Mich., 1989. 

Microscopists in every technical field use the microscope to characterize, compare, and identify a wide variety of substances, eg, protozoa, bacteria, vimses, and plant and animal tissue, as well as minerals, building materials, ceramics, metals, abrasives, pigments, foods, dmgs, explosives, fibers, hairs, and even single atoms. In addition, microscopists help to solve production and process problems, control quaUty, and handle trouble-shooting problems and customer complaints. Microscopists also do basic research in instmmentation, new techniques, specimen preparation, and appHcations of microscopy. The areas of appHcation include forensic trace evidence, contamination analysis, art conservation and authentication, and asbestos control, among others. 

---