Heated bone

Fig. 11.17 XRD patterns of bone hydroxyapatite and sintered stoichiometric hydroxyapatite. (Bone hydroxyapatite was obtained by heating bone of pig at 600°C).

Either bone phosphate (bone ash), obtained by heating bones to whiteness, or the mineral phosphorite is used as a source of tribasic calcium phosphate, which is the starting material in the industrial production of dibasic sodium phosphate. 

The a form can be prepared by heating a dry mix of calcium pyrophosphate and chalk (5.65), while the P form (whitlockite) is obtained from aqueous Ca(OH>2 and H3PO4 with pH > 6.0. The P form is also obtained by heating bone hydroxyapatite at 700 C. 

Buckley, M. (2008) Species identification in ancient and heated bone fragments using protein mass spectrometry. Unpublished PhD thesis. University of York, York. 

The recipe for Greek fire was kept a secret, so its discovery had little impact on the development of chemistry. Even today we are uncertain of its composition. It seems likely that crude petroleum was distilled to give a liquid similar to petrol (gasoline), and that this was rendered flammable on contact with water by the addition of other substances. It has been suggested that a mixture of quicklime and sulphur was added, but it is more likely that calcium phosphide was used. Calcium phosphide could have been made by heating bones, lime and urine together. It produces the spontaneously inflammable phosphine on contact with water. 

The ESR spectra from bone samples fall into three types, which are correlated with the thermal history of the samples. Bone standard samples that have not been heated above the temperature needed to dry them (40 C), and prehistoric bone samples that appear never to have been heated, display a weak ESR signal. The dried standards have a signal that seems to correlate with the signals of heated bone standards, but is very weak. The (apparently) unheated prehistoric bone samples have a signal that has g = 2.0040 at the peak of the spectrum. This spectrum appears to be that of a randomly oriented species with three distinct g values. It is hard to fit the spectrum to a simulated spectrum... 

In a related study, a biomass material, bone char was investigated by Ma et al. (2008) for its feasibility as a cost-effective biosorbent for F removal from drinking water. The amorphous biosorbent powder, which is composed mainly of calcium phosphate and a small amount of carbon, was prepared by heating bone-biomass. The adsorption capacity of the hone char was shown to be better than that of activated aluminum and tourmaline (i.e., crystal horon sUicate mineral compounded with elements such as aluminum, iron, magnesium, sodium, hthium, or potassium). Removal of F was attributed to the processes of ion binding and ion exchange between bone char and F". The authors developed static and kinetic models which provided a satisfactory prediction of F concentration after adsorption. Experiments with fixed-bed columns... 

Heating bone tissue to a temperature of about 750 °C ensures a complete biological decontamination [3]. When the temperature increases above this threshold the start of a complex metamorphic transformation of the bone tissue occurs. The thermal decomposition of stoichiometric hydroxyapatite undergoes at temperatures over 800 °C, with the initial formation of oxy-hydroxyapatite and oxy-apatite, followed by the oxy-apatite decomposition into various forms of tricalcium phosphate and/or calcium oxide [4,48]. An endothermic phenomenon can be identified in the range 800-1000 C, assigned to the modification of the hydroxyapatite crystalline lattice parameters, which takes place shortly before the initiation of its decomposition in beta-tricalcium phosphate [(3-TCP, CajCPO ) ] [49]. 

Other results, obtained by heating bone samples from different species in air atmosphere, showed that the hydroxyapatite transformation starts around 800 °C, along with the identification at 1000 °C of a reduced quantity of calcium oxide while in argon atmosphere the formation of calcium oxide, tetracalcium phosphate and tricalcium phosphate was observed above the 1000 °C temperature. 

Fundamentally, introduction of a gaseous sample is the easiest option for ICP/MS because all of the sample can be passed efficiently along the inlet tube and into the center of the flame. Unfortunately, gases are mainly confined to low-molecular-mass compounds, and many of the samples that need to be examined cannot be vaporized easily. Nevertheless, there are some key analyses that are carried out in this fashion the major one i.s the generation of volatile hydrides. Other methods for volatiles are discussed below. An important method of analysis uses lasers to vaporize nonvolatile samples such as bone or ceramics. With a laser, ablated (vaporized) sample material is swept into the plasma flame before it can condense out again. Similarly, electrically heated filaments or ovens are also used to volatilize solids, the vapor of which is then swept by argon makeup gas into the plasma torch. However, for convenience, the methods of introducing solid samples are discussed fully in Part C (Chapter 17). 

Protein-Based Adhesives. Proteia-based adhesives are aormaHy used as stmctural adhesives they are all polyamino acids that are derived from blood, fish skin, caseia [9000-71 -9] soybeans, or animal hides, bones, and connective tissue (coUagen). Setting or cross-linking methods typically used are iasolubilization by means of hydrated lime and denaturation. Denaturation methods require energy which can come from heat, pressure, or radiation, as well as chemical denaturants such as carbon disulfide [75-15-0] or thiourea [62-56-6]. Complexiag salts such as those based upon cobalt, copper, or chromium have also been used. Formaldehyde and formaldehyde donors such as h exam ethyl en etetra am in e can be used to form cross-links. Removal of water from a proteia will also often denature the material. 

The fire assay, the antecedents of which date to ancient Egypt, remains the most rehable method for the accurate quantitative determination of precious metals ia any mixture for concentrations from 5 ppm to 100%. A sample is folded iato silver-free lead foil cones, which are placed ia bone-ash cupels (cups) and heated to between 1000 and 1200°C to oxidize the noimoble metals. The oxides are then absorbed iato a bone-ash cupel (ca 99%) and a shiny, uniformly metaUic-colored bead remains. The bead is bmshed clean, roUed fiat, and treated with CP grade nitric acid to dissolve the silver. The presence of trace metals ia that solution is then determined by iastmmental techniques and the purity of the silver determined by difference. 

Interest in the synthesis of diamond [7782-40-3] was first stimulated by Lavoisier s discovery that diamond was simply carbon it was also observed that diamond, when heated at 1500—2000°C, converted into graphite [7782-42-5]. In 1880, the British scientist Haimay reported (1) that he made diamond from hydrocarbons, bone oil, and lithium, but no one has been able to repeat this feat (2). About the same time, Moissan beheved (3) that he made diamond from hot molten mixtures of iron and carbon, but his experiments could not be repeated (4,5). 

The plate dryer is limited in its scope of apphcations only in the consistency of the feed material (the products must be friable, free flowing, and not undergo phase changes) and diying temperatures up to 320°C. Applications include speci ty chemicals, pharmaceuticals, foods, polymers, pigments, etc. Initial moisture or volatile level can be as high as 65 percent and the unit is often used as a final dryer to take materials to a bone-dry state, if necessary. The plate dryer can also be used for heat treatment, removal of waters of hydration (bound moisture), solvent removal, and as a product cooler. 

Charcoal is generally satisfactorily activated by heating gently to red heat in a crucible or quartz beaker in a muffle furnace, finally allowing to cool under an inert atmosphere in a desiccator. Good commercial activated charcoal is made from wood, e.g. Norit (from Birch wood), Darco and Nuchar. If the cost is important then the cheaper animal charcoal (bone charcoal) can be used. However, this charcoal contains calcium phosphate and other calcium salts and cannot be used with acidic materials. In this case the charcoal is boiled with dilute hydrochloric acid (1 1 by volume) for 2-3h, diluted with distilled water and filtered through a fine grade paper on a Buchner flask, washed with distilled water until the filtrate is almost neutral, and dried first in air then in a vacuum, and activated as above. To improve the porosity, charcoal columns are usually prepared in admixture with diatomaceous earth. 

The results of heat and water stress experiments (Table 12.3) show that these factors had no significant effects on nitrogen isotope ratios of bone collagen or hair. The mean collagen-diet difference (A Nco-d) values of the water-restricted litters ranged from 2.6 %o for group 10 on diet A (36°, water ad... 

Solid materials susceptible to self-heating in air Activated charcoal Animal feedstuffs Beans Bone meal, bone black Brewing grains, spent Leather scrap... 

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