Toxic cadmium

Fire Hazards - Flash Point Not flammable Flammable limits in Air (%) Not flammable Fire Extinguishing Agents Not pertinent Fire Extinguishing Agents Not To Be Used Not pertinent Special Hazards cf Combustion Products Toxic cadmium oxide fumes may form Behavior in Fire No data Ignition Tenqterature Not pertinent Electrical Hazard Not pertinent Burning Rate Not pertinent. 

Battery technology continues to advance at a steady pace. Lithium batteries and nickel-metal-hydride batteries are now commonplace. These new rechargeable batteries eliminate the need for toxic cadmium and store more energy per unit mass. The detailed chemistry that underlies the newest advances in battery technology involves principles that are beyond the scope of an introductory course. 

Like many technological innovations, nickel-cadmium batteries carry risks as well as benefits. After being discharged repeatedly, they eventually wear out. In theory, worn-out nicad batteries should be recycled. In practice, however, many end up in garbage dumps. Over time, discarded nicad batteries release toxic cadmium. The toxicity of this substance makes it hazardous to the environment, as cadmium can enter the food chain. Long-term exposure to low levels of cadmium can have serious medical effects on humans, such as high blood pressure and heart disease. 

In rat developmental studies, fetal effects including delayed ossification and decreased locomotor activity occurred at doses that also caused maternal toxicity. Cadmium sulfate injected into the lingual vein of female hamsters on day 8 of pregnancy caused a high incidence of resorption and malformed offspring. Acute necrosis of rat testes followed large doses orally or parenterally, but testicular effects have not been reported thus far in humans." ... 

Toxicity. Cadmium pigments are cadmium compounds with a low solubility, however, small quantities of cadmium dissolve in dilute hydrochloric acid (concentration equivalent to stomach acid), and in cases of long-term oral intake of cadmium pigments, they can accumulate in the human body. On inhalation of subchronic amounts of cadmium pigments, a small proportion of cadmium is biologically available [3.115], [3.116]. 

Kidney. Because the kidney is the main excretory organ of the body, it is a common target organ for metal toxicity. Cadmium and mercury, in particular, are potent nephro-toxicants and are discussed more fully in the following sections and in Chapter 15. 

Endogenous substances other than metallothionein may be involved in minimizing the effects of heavy metals and excreting them from the body. Hepatic (liver) glutathione, discussed as a phase II conjugating agent in Section 7.4, plays a role in the excretion of several metals in bile. These include the essential metals copper and zinc toxic cadmium, mercury(II), and lead(II) ions and organometallic methyl mercury. 

Dimethylcadmium, (CH3)2Cd, is an oily liquid at room temperature and has a very unpleasant odor. The compound melts at -4.5"C and boils at 106°C. It decomposes in contact with water. Diethyl-cadmium is likewise an oil it melts at -21°C, boils at 64°C, and reacts explosively with oxygen in air. Dipropylcadmium, (C3H7)2Cd, is an oil that melts at -83°C, boils at 84°C, and reacts with water. The dialkyl cadmium compounds are distillable, but decompose above about 150°C, evolving toxic cadmium fume. 

Since the kidneys are the main depot for cadmium, they are of greatest concern for cadmium toxicity. Cadmium interferes with the proximal tubule s reabsorption function. This leads to abnormal actions of uric acid, calcium, and phosphorus. Amino aciduria (amino acids in the urine) and glucosuria (glucose in the urine) result in later stages, proteinuria (protein in the urine) results. When this happens, it is assumed that there is a marked decrease in glomerular filtration. Long-term exposure to cadmium leads to anemia, which may result from cadmium interfering with iron absorption. 

C4HsCd04 Noncombustible solid. The solution is basic reacts with acids, producing heat. Incompatible with strong oxidizers, elemental sulfur, selenium, sulfides, tellurium, nitrates. In the heat of fire, toxic cadmium oxide fumes may form. CADMIUM BROMIDE (7789-42-6) CdBrj Noncombustible solid. Hydrolyzes in water, forming cadmium and bromic acid. Reacts with sulfides. Aqueous solution is inconqiatible with potassium. Incompatible with sulhiric acid, alkalis, ammonia, aliphatic amines, alkanolamines, alkylene oxides, amides, epichlorohydrin, organic anhydrides, isocyanates, nitromethane, vinyl acetate. 

The CdTe, CIS, and CIGS PV module technologies are in continuous development GeU efficiency, process optimization, tellurium supply, use and recycling of the extremely toxic cadmium metal, price vulnerability, solar tracking, and market viability are the main issues related to the commercial success of thin-film solar technologies such as GdTe PV solar cells. 

Gas-proof constructions are often designed like commercial batteries (including button cells), so they can replace the primary cells in portable electric and microelectric devices. Meanwhile, usage of nickel-cadmium batteries is strongly limited by law because of the dangers related to toxic cadmium. 

Nickel-metal-hydride (NiMH) battery (13.5) Secondary (rechargeable) battery used in many small electronic devices involves the oxidation of hydrogen from a metal hydride and the reduction of nickel oxyhydroxide (NiO(OH)). Compared with nicad batteries, NiMH eliminates the use of toxic cadmium and is less prone to memory effects. 

Mined apatite is a viable source of uranium and toxic cadmium (Tables 2.15 and 4.3). Concern has been expressed that both these elements could enter the food chain via fertilisers made from wet process phosphoric acid. Significant quantities of Pb, Hg and Cu may also be present but concentrations of all trace elements can be very sensitive to exact deposit location [88] (Table 2.16). Prolonged... 

Improper disposal of Ni-MH batteries poses less environmental hazard than that of Ni-Cd because of the absence of toxic cadmium. 

Some metals will displace other metals from a salt. Advantage is taken of this for the removal of toxic heavy metals from water solutions of the metals salts by reaction with a more active metal, a process called cementation. For example, metallic iron can be reacted with wastewater containing dissolved toxic cadmium sulfate to isolate solid cadmium metal and leave solid cadmium metal and a new salt, iron(II) sulfate ... 

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