Metals subcategory complexed

The concentrations of metals found in complexed metals subcategory raw waste streams are presented in Table 9.6. Complexed metals may occur in a number of unit operations but come primarily from electroless and immersion plating. The most commonly used metals in these operations are copper, nickel, and tin. Wastewaters containing complexing agents must be segregated and treated independently of other wastes in order to prevent further complexing of free metals in the other streams. 

Concentrations of Pollutants Found in the Complexed Metals Subcategory of Raw Wastewater... 

Mixed-Metal Oxide Pig ments. Mixed-metal oxide pigments can be considered a subcategory of complex inorganic color pigments. The name, mixed-metal oxides, does not, however, represent the reaUty as these pigments are not mixtures but rather soHd solutions or compounds consisting... 

Table 9.2 lists the unit operations associated with each of the seven industry subcategories (raw waste characteristics). Common metals are found in the raw waste of all 44 unit operations. Precious metals are found in only seven unit operations complexed metals are found in three unit operations hexavalent chromium is found in seven unit operations and cyanide is found in eight unit operations. Within the organics, oils are found in 22 unit operations and solvents are found in nine unit operations. A unit operation will often be found in more than one subcategory. 

Data source EGO Combined Data Base Point source Metal finishing Subcategory Common metals precious metals complexed metals hexavalent chromium solvents... 

A typical transition metal atom has nine valence shell orbitals one s, three p, and five d, in which it accommodates valence electrons that bond with other moieties known as ligands (usually represented by the letter L) to form two types of bonds, covalent and coordinated. In a typical covalent bond, one or more electrons are shared between two atoms. However, the electrons that constitute a bond need not be equally shared in fact, all of the electrons can come from just one of the atoms. Although this kind of bond is also a covalent bond, it is usually regarded as a subcategory of the covalent bond and is referred to as a coordinate bond. This ability to form these two types of bonds with a number of ligands is responsible for the unique catalytic properties of the transition metals and their complexes. 

---