Dirty iron

FIGURE 11.5 Half-held spectrum of two interacting cubanes. The signal from dihydropyrimidine dehydrogenase is of low intensity due to the relative weakness of the dipolar interaction. The g = 4.3 signal is a dirty iron contamination. 

FIGURE 11.9 An extremely broad EPR signal form the superparamagnetic core in ferritin. The spectrum is from Pyrococcus furiosus ferritin. The sharp signal at g = 4.3 (circa 1570 gauss) is from a trace of contaminating dirty iron. ... 

All of these various homopolymeric carboxylates may form soluble complexes with hardness salts in BW, similar to EDTA and NTA. However, using polyacrylates in dirty boilers with a considerable excess of iron or calcium may cause metal acrylate deposition. 

Some basic BW treatment objectives include keeping boiler surfaces clean and corrosion-free to minimize fuel bills and managing variable quality FW smoothly and efficiently to limit upsets and other downstream problems. But the nature of potential boiler deposition problems changes with increases in pressure and, simply put, is primarily concerned with a reduction in simple, hardness-related deposits and an increase in complex, iron oxide deposits. The effect of dirty boilers on fuel costs can be seen in Figure 10.4. 

Where the rapid removal of corrosion debris occurs or where amine feed rates are initially kept low and the condensate still contains iron oxide, the dirty condensate should be polished or simply dumped until the condition improves. 

Rabah, M. A. Recovery of iron and copper from spent HC1 used to clean up dirty car radiators. Hydrometallurgy... 

The nodules range in diameter from 20 pm to 15 cm, with most between 1 and 10 cm. As shown in Table 18.4, they are composed predominantly of manganese and iron oxides (about 20% each). They are generally dark brown and have the appearance of dirty, lumpy potatoes or hamburgers, with some being spherical and others more discoidal. 

A Dirty Silicate Story A friend of one of the authors is an astronomer—as well as a professional mineral dealer—who became interested in dirty silicates as candidates for interstellar dust. He therefore selected for determination of the blackest natural silicate mineral in his possession, the coal-black mineral hornblende, which contains a high concentration of impurities such as iron. A slice about 100 jam thick was polished, and transmission was measured in a recording spectrophotometer. The fact that appreciable light was transmitted for all near-infrared and visible wavelengths indicated that k was rather small. Calculations indeed confirmed that k was less than 10 4 between about 6 and 0.3 jum. And yet this was the blackest silicate in the possession of a professional collector. It is not easy to find A = 0.01 in the band gap region of... 

Sometimes, deposits accumulate on the exterior of tubes. These deposits are unavoidable when heavy industrial fuel oil is fired.Such fuel oils contain high concentrations of vanadium, nickel, sodium, and iron (in that order of concentration). These metals deposit as an ash, on the exterior of both the radiant- and convective-section tubes. The ash will get very hot and will turn sections of tubes yellow, or even whitish silver. This is not an indication of tube overheating. If the deposits get thick enough, they will interfere with the rate of heat absorption by the tube. It is very difficult to distinguish between a real hot spot and glowing ash. Dirty fuel gas also leads to ash formation on the radiant surface of tubes. 

Iron/sulfur mixture Dirty yellow powder Iron powder attracted to it Iron powder reacts as above... 

I our environment is made up of many important solutions, or homogeneous mixtures. The air you breathe and the liquids you drink are solutions. So are many of the metallic objects that you use every day. The quality of a solution, such as tap water, depends on the substances that are dissolved in it. Clean water may contain small amounts of dissolved substances, such as iron and chlorine. Dirty water may have dangerous chemicals dissolved in it. 

Sodium hydroxide solution white precipitate of iron(II) hydroxide, Fe(OH)2, in the complete absence of air, insoluble in excess, but soluble in acids. Upon exposure to air, iron(II) hydroxide is rapidly oxidized, yielding ultimately reddish-brown iron(III) hydroxide. Under ordinary conditions it appears as a dirty-green precipitate the addition of hydrogen peroxide immediately oxidizes it to iron(III) hydroxide. 

Iron Verification Above 0.3 mg/l can cause problems of dirty water, Controlled by treatment optimization... 

Next we pour some iron filings and some powdered sulfur into a large test tube and stir them together. The sample appears to be a dirty yellow, but if we look closely, we can see yellow specks and black specks. If we hold a magnet next to the test tube (Figure 1.3c), the black particles (with some yellow particles clinging to them) are attracted by the magnet. When we pour some carbon disulfide on the sample, the liquid turns yellow. We pour off that liquid and pour on more carbon disulfide until no yellow solid remains in the sample. When we evaporate the carbon disulfide in a fume hood, we get a... 

Iron concentrations as low as 0.3 mg/L and manganese concentrations as low as 0.05 mg/L can cause dirty water complaints. At these concentrations, the water may appear clear but imparts brownish colors to laundered goods. Iron also affects the taste of beverages such as tea and coffee. Manganese flavors tea and coffee with medicinal tastes. 

To demonstrate that the various potential high-level waste compositions are all amenable to immobilization, the WFP program uses two standard waste compositions. These are a clean waste, designated PW-4b (which is essentially first-cycle raffinate), and a dirty waste (designated PW-6), which contains large amounts of sodium and iron see Table II). It should be noted that there are other possible constituents of high-level wastes, such as fiuoride, mercury, and soluble poisons which are not included in the initial demonstration program. 

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