LEAD-ZINC Group

Mnnual bulletin. International Lead Zinc Study Group, London, 1993. 

Table 4.10 lists some typical physical properties for nonferrous slags. Because they have similar properties, lead, lead-zinc, and zinc slags are grouped together. 

There are two major groups of arsenical gold ores of economical value. These are the massive base metal sulphides with arsenical gold (i.e. the lead-zinc Olympias deposit, Greece) and arsenical gold ores without the presence of base metals. Massive, base metal... 

There are a variety of mixed sulphide oxide ores and oxide lead zinc ores, and these ores cannot be classified into any specific group due to the vast differences in geology and mineral compositions. Only limited literature is available on the geological and miner-alogical characteristics of these ores. From a processing point of view, these ores can be classified into the following groups ... 

Esperite is a calcium lead zinc-silicate mineral. The crystal structure is mono-clinic-prismatic (P21/m) with a B2 jm group. Steady-state laser-induced luminescence of esperite was ascribed to Mn " in Zn and Ca positions, accompanied by Dy " and Sm " lines. Besides that reabsorption lines of Nd " and have been found (Gorobets and Rogojine 2001). The laser-induced time-resolved... 

The most important raw materials for the production of non-ferrous metals, such as copper, lead, zinc, nickel, cobalt, molybdenum, antimony and cadmium, are the sulfide minerals. The use of collectors containing various thio-type functional groups has proved to be the most successful in the flotation of these minerals. Some of these compounds are shown in Table 1. 

Fig. 9-9. Acid released H2S content of soils along four traverses over a lead-zinc ore body beneath thick lithic cover in China K]d = Cretaceous red sediments, J,gn = Jurassic Lingkou Group, P2L = Permian Leping formation.

If solvent extraction is carried out in the presence of cyanide, the zinc group of metals (Zn, Cd, Hg) is complexed and they will not extract. Addition of citrate complexes the elements of the ammonia group (Fe, Al, etc.) so that their hydroxides will not precipitate. The precipitation of the alkaline earth phosphates can be prevented by the addition of hexametaphosphate (Jl). Under these conditions, Bi(III), TI(I), and Sn(II) interfere in alkaline solution. The bismuth can be removed by preextraction at pH 3. Alternatively, if a positive lead test is found, bismuth could be ruled out or confirmed by back-extracting at pH 3. If bismuth is present, it will remain in the organic layer while lead will go into the aqueous phase. Extraction of thallium can be prevented by extracting the lead at pH 6.0-6.4 with chloroform. Or the thallium can be back-extracted at this pH this requires much closer control of the pH. The oxidation of dithizone by air is catalyzed by the presence of significant amounts of manganese (II). 

Lead, lead-zinc, - Slags of this group are often black to red in color and glassy and zinc slag They have sharp, angular particles that are cubic in shape... 

Stabilizers are almost invariably added to PVC to improve its heat and light stability. The species found effective in stabilizing PVC are those that are able to absorb or neutralize HCl, react with free radicals, react with double bonds, or neutralize other species that might accelerate degradation. Lead compounds, such as basic lead carbonate and tribasic lead sulfate, and metal soaps of barium, cadmium, lead, zinc, and calcium are used as stabilizers. Obviously, they can react with HCl. Epoxy plasticizers aid in stabilizing the resin. Another group of stabilizers are the organotin compounds, which find application because of their resistance to sulfur and because they can yield crystal-clear compounds. 

Ide-Ektessabi et al. (2005) used X-ray fluorescence spectrosopy to measnre the concentrations of lead and several trace elements in the brains of three gronps of patients. The groups included patients with (1) diffnse neurofibrillary tangles with calcification (DNTC), (2) Alzheimer s disease (AD) with calcification, and (3) AD without calcification. They found high concentrations of lead, zinc, and calcium in the brain tissues of DNTC and AD patients with calcification, but no lead in the tissues of AD patients without calcification. There was a strong correlation between degree of calcification and lead concentration in the calcified areas of the brain in these patients. 

Figure 2 - World Refined Metal Consumption (1960-1999) Source International Lead Zinc Study Group (ILZSG) and IZA...

ILZG, Economics of Lead and Zinc , International Lead Zinc Study Group - Statistics. httD //www.ilzsg.org/statisticsasp pg=eco. 2000. 

Copper, lead, zinc, tin, mercury, and cadmium are often grouped together simply because they are not used to alloy with iron. Copper metal conducts electricity well and can be shaped into wires, so it has been used mainly in electric lines and electric motors. Lead and mercury are used much less than in the past because of their toxicity. Lead is still used in batteries for vehicles, and mercury is used in some batteries, electrical switches, and for some chemical compounds. Zinc or tin are used in protective coatings for steel to keep it from rusting. Zinc oxide is added to paint to produce a white color and to a variety of lotions to prevent sunburn. Many so-called tin cans contain tin plated on other metals. 

Tin bronzes tend to be used primarily in the cast form in which they are modified by further alloy additions of lead, zinc, and nickel. Contemporary uses include pumps, valves, gears, and bushings. This group of alloys has fair resistance to impingement and good resistance to biofouling. 

A number of studies have appeared in which two types of comparisons were made (1) modeled versus measured children s PbB values in batch simulations using data sets of environmental and blood Pb measurements and (2) comparisons across models using children s PbB simulations. For the first type, Hogan et al. (1998) compared simulated exposures as PbB GMs, with measured PbB values in three smelter communities (sample sizes in parentheses) Madison County, EL (333) Pahnerton, PA (34) and the smelt-ing/mining area of Galena, KS/Jasper County, MO (111), within the Tri-State lead-zinc belt. The measured geometric PbB means for the tested children in the KS/MO, Madison County, IL, and Palmerton, PA, groups were 5.2, 5.9, and 6.8 pg/dl, respectively. The modeled values for these same... 

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