Pressure roasting

VCR (Viobin Cocoa Replacer) is ".pressure-roasted defatted wheat germ, ground to a fine powder which is similar in color and texture to processed cocoas...The toasting process develops aroma and taste characteristics that complement...cocoa..." Such aroma as it has, and it would not be mistaken for cocoa, can be attributed to Maillard reactions taking place during toasting. It is manufactured and sold by the Viobin Corporation, Monticello, Illinois. 

Australian Vanadium—Uranium Ore. A calcareous camotite ore at YeeHrrie, AustraHa, is iU-suited for salt roasting and acid leaching. Dissolution of vanadium and uranium by leaching in sodium carbonate solution at elevated temperature and pressure has been tested on a pilot-plant scale... 

These properties can be partly produced by fiber disgestion (steam explosion, steam pressure, thaw roasting process, water roasting process [8,9]), as well as by a direct application to the fiber. 

Chalcopyrite, CuFeS2, is an important source of copper. A typical chal-copyrite ore contains about 0.75% Cu. What volume of sulfur dioxide at 25°C and 1.00 atm pressure is produced when one boxcar load (4.00 X 103 ft3) of chalcopyrite ore (d = 2.6 g/cm3) is roasted Assume all the sulfur in the ore is converted to S02 and no other source of sulfur is present. 

The basic process outline is depicted in Figure 5.2 moist un-roasted coffee beans and CO2 are fed counter-currently into the extractor under supercritical conditions. Caffeine is selectively extracted into the CO2 and this stream is led to a water-wash column to remove caffeine at a reduced pressure, the CO2 being recycled back to the extraction column. Extraction of the caffeine into water is necessary to avoid dropping the CO2 pressure too low, since compression is energy-intensive. There is now the problem of separating the caffeine (which is used in soft drinks and pharmaceu-... 

The roasting process gives rise to the formation of S02 and As203, both of which are environmentally undesirable. For this reason, roasting, although still practised, is less favorably disposed as compared with the newer alternatives of pressure or biological oxidation. 

As seen in the above equations, the aqueous oxidation processes convert sulfur in the feed to dissolved sulfate, while arsenic is oxidized and precipitated as ferric arsenate compounds. So, problems of the emission of sulfur and arsenic oxides caused by roasting are avoided in the aqueous oxidation processes. The two different industrial methods which achieve the oxidation reactions are pressure oxidation and biological oxidation. 

Roasted and ground coffee is packed into columns and percolated by the passage of hot water under pressure at about 340°F. The use of pressurized boiling water not only brings about the dissolution of the most readily water-soluble coffee extractables, it also causes the solubilization and possibly the hydrolysis of complex carbohydrates. Water-soluble compounds of a smaller molecular weight are produced. The extent of possible... 

Several examples of arsenic speciation in wastes resulting from pressure oxidation, roasting and smelting, and impacted soil are given in this manuscript with the overall goal to promote further research in this area. 

Prior to gold extraction by cyanidation, refractory gold ores are either roasted or pressure oxidized to liberate the gold contained as submicroscopic particles or in solid solution in arsenopyrite and arsenic-rich pyrite. Gold extraction from such ores require roasting or pressure oxidation or bacterial oxidation prior to cyanidation to destroy the sulfide structure. 

Separation of arsenopyrite and pyrite is important from the point of view of reducing downstream processing costs. Normally, roasting or pressure oxidation followed by cya-nidation is used to recover gold. 

The following hypotheses was tested in the first approximation if the vaporization of volatile oxides, sulfides, and metals of all the considered chemical elements at roasting and/or conversion temperature plays a significant role in the contamination of Karabash atmosphere, their calculated equilibrium pressure over the Cu-concentrate, slag, matte or copper melt (or their chemical composition) should strongly correlate with the detected abundance of these elements in snow samples. If such a significant correlation is detected, the corresponding process exerts primary... 

Flow Measurements Measurement of flow rates of clean gases presents no problem. Flow measurement of gas streams containing solids is almost always avoided. The flow of solids is usually controlled but not measured except solids flows added to or taken from the system. Solids flows in the system are usually adjusted on an inferential basis (temperature, pressure level, catalyst activity, gas analysis, heat balance, etc.). In many roasting operations, the color of the calcine discharge material indicates whether the solids feed rate is too high or too low. 

The metallic arsenic is obtained primarily from its mineral, arsenopyrite. The mineral is smelted at 650 to 700°C in the absence of air. However, the most common method of production of the metal involves reduction of arsenic trioxide, AsOs with charcoal. Arsenic trioxide is produced by oxidation of arsenic present in the lead and copper concentrates during smelting of such concentrates. The trioxide so formed, readily volatilizes and is collected in a dust flue system where further treatment and roasting can upgrade the trioxide content. The trioxide vapors are then condensed and further purified by pressure leaching and recrystallization techniques. It is then reduced with charcoal to give metallic arsenic. 

Metallic beryllium is produced by reduction of beryllium halide with sodium, potassium or magnesium. Commercially, it is obtained primarily from its ore, beryl. Beryllium oxide is separated from silica and alumina in ore by melting the ore, quenching the solid solution, and solubilizing in sulfuric acid at high temperatures and pressure. Silica and alumina are removed by pH adjustment. Beryllium is converted to its hydroxide. Alternatively, beryl is roasted with complex fluoride. The products are dissolved in water and then pH is adjusted to produce beryllium hydroxide. 

The maximum permitted temperature for the production of process flavours is around 180 °C, as defined by legal regulations, but in general, the temperatures actually used are much lower in order to be able to reach a broad variety of different flavour profiles, such as cooked, boiled, fried, roasted and shallow-fried notes. The pressure during the reaction is usually below 10 bar (10,000 hPa). 

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