Zinc fertilizers

The level of natural versus man-made emissions to the environment are of a similar magnitude. SoH erosion is the major contributor of natural emissions with zinc mining, zinc production facHities, iron and steel production, corrosion of galvanized stmctures, coal and fuel combustion, waste disposal and incineration, and the use of zinc fertilizers and pesticides being the principal anthropogenic contributors. 

Zinc fertilizers made from recycled hazardous secondary materials. U.S. EPA promulgated a conditional exclusion from the definition of solid waste for hazardous secondary materials that are recycled to make zinc fertilizers or zinc fertilizer ingredients. Zinc, an important micronutrient for plants and animals, can be removed from zinc-rich manufacturing residue and used to produce zinc micronutrient fertilizer. A second conditional exclusion applies to the zinc fertilizer products made from these secondary materials. 

Soils in the North China Plain and Loess Plateau regions contained 0.04-3.01 mg/kg DTPA-extractable Zn with an average of 0.44 mg/kg. The concentrations of DTPA-extractable Zn in northern China are presented in Table 7.7. In the loessial soils of the Loess Plateau, 64% of the soil samples had less than 0.5 mg/kg of bioavailable Zn. The bioavailable Zn in the arid soils of North China varied from 0.08-11.84 mg/kg with an average of 1 mg/kg, with 41% of the soil samples having < 0.5 mg/kg of bioavailable Zn. The average amount of bioavailable Zn in calcareous soils was 0.35 mg/kg (trace - 1.12 mg/kg). The North China Plain and Loess Plateau are major Zn-deficient regions in China. Calcareous paddy soils frequently displayed Zn deficiency in rice. Zinc fertilizers have been applied to rice, maize, sorghum, wheat, cotton and fruit trees where bioavailable Zn was less than 0.5 mg/kg. 

Zinc fertilizer is used to supply plants to correct for Zn deficiency. In 1987, Zn fertilizers were used in an area of more than 2,670,000 ha in China (Zhu, 1996). Zinc inorganic salts, chelate forms, and biosolids such as sewage sludge have been applied to arid and semi-arid soils to correct for Zn deficiency. 

Gallagher P.J., Murphy L.S., Ellis R.J. Effects of temperature and soil pH on effectiveness of four zinc fertilizers. Commu Soil Sci Plant Anal. 1978 9 115-126. 

Jiao Y., Bailey L.D., Grant C.A. Effects of phosphorus and zinc fertilizer on cadmium uptake and distribution in flax and durum wheat. J Sci Food Agri 2004 84 777-785. 

Sajwan K.S., Lindsay W.L. Effect of redox, zinc fertilization and incubation time on DTPA-extractable zinc, iron and manganese. Commun Soil Sci PlantAnal 1988 19 1-11. 

Cayton MT, Reyes ED, Neue HU. 1985. Effect of zinc fertilization on the mineral nutrition of rices differing in tolerance to zinc deficiency. Plant and Soil 87 319-327. 

When zinc fertilizers are used on soils deficient in zinc, crop production may be increased even though the zinc concentration in the plant tissues and especially in the seed show no increase. With higher levels of zinc fertilization, the zinc concentration in plants may increase. Some evidence shows that the value of food and feed crops as sources of dietary zinc can be improved by using zinc fertilizers at rates exceeding those required for optimal plant growth. However, very high rates of zinc fertilization can depress crop yields. 

US Environmental Protection Agency (US EPA) (2002a) Zinc fertilizers made from recycled hazardous secondary materials. Federal Register, 67(142), 48393-415. 

Mortvedt JJ and Gilkes RJ (1993) Zinc fertilizers. In Robson AD, ed. Developments in Plant and Soil Sciences, Vol. 55. Zinc in Soils and Plants, pp. 33—44. Kluwer Acad Pub, Dordrecht. 

Mugwira LM and Knezek BD (1971) Navy bean responses to zinc fertilizers. Commun Soil Sd Plant Anal 2 337-343. 

The appearance of a zinc deficiency as a result of extensive surface erosion or of loss of the A horizon by land leveling operations (29, 30, 127) may partly be ascribed to higher pH values below the surface horizon but principally to a loss of the principal soil reservoir of zinc as well as to a loss of the organic matter, the latter being necessary for the periodic reduction of the hydrous oxides to make the occluded heavy metals available. That the deficiency on these lands is not simply a loss of zinc is shown by the frequent failure of a single zinc fertilization to prevent zinc deficiency on land which has had the surface soil removed by leveling (29, 30, 127) or erosion (J29). 

In paints, zinc oxide serves as a mildewstat and acid buffer as well as a pigment. The oxide also is a starting material for many zinc chemicals. The oxide supphes zinc in animal feeds and is a fertilizer supplement used in zinc-deficient soils. Its chemical action in cosmetics (qv) and dmgs is varied and complex but, based upon its fungicidal activity, it promotes wound healing. It is also essential in nutrition. Zinc oxide is used to prepare dental cements in combination with eugenol and phosphoric and poly(acrylic acid)s (48) (see Dental materials). 

Agricultural Use. Citric acid and its ammonium salts are used to form soluble chelates of iron, copper, magnesium, manganese, and zinc micronutrients in Hquid fertilizers (97—103). Citric acid and citrate salts are used in animal feeds to form soluble, easily digestible chelates of essential metal nutrients, enhance feed flavor to increase food uptake, control gastric pH and improve feed efficiency. 

Ammonia Used in refrigeration, chemical processes such as dye making, explosives, lacquer, fertilizer Textiles, chemicals Corrosive to copper, brass, aluminum, and zinc high concentration producing chemical burns on wet sldn... 

Particulate emissions from zinc processing are collected in baghouses or ESPs. SO2 in high concentrations is passed directly to an acid plant for production of sulfuric acid by the contact process. Low-concentration SO2 streams are scrubbed with an aqueous ammonia solution. The resulting ammonium sulfate is processed to the crystalline form and marketed as fertilizer. 

Sulfide ores usually contain small amounts of mercury, arsenic, selenium, and tellurium, and these impurities volatilize during the ore treatment. All the volatilized impurities, with the exception of mercury, are collected in the dust recovery systems. On account of its being present in low concentrations, mercury is not removed by such a system and passes out with the exit gases. The problem of mercury contamination is particularly pertinent to zinc plants since the sulfidic ores of zinc contain traces of mercury (20-300 ppm). The mercury traces in zinc sulfide concentrates volatilize during roasting and contaminate the sulfuric acid that is made from the sulfur dioxide produced. If the acid is then used to produce phosphatic fertilizers, this may lead to mercury entering the food chain as a contaminant. Several processes have been developed for the removal of mercury, but these are not yet widely adopted. 

Transporting the dust to an offsite processor for thermal treatment and removal of zinc, chemical fixation, glassification, or fertilizer manufacture... 

For the most part, the zinc materials recovered from secondary materials such as slab zinc, alloys, dusts, and compounds are comparable in quality to primary products. Zinc in brass is the principal form of secondary recovery, although secondary slab zinc has risen substantially over the last few years because it has been the principal zinc product of electric arc furnace (EAF) dust recycling. Impure zinc oxide products and zinc-bearing slags are sometimes used as trace element additives in fertilizers and animal feeds. About 10% of the domestic requirement for zinc is satisfied by old scrap. 

Agbenin J.O. Zinc fractions and solubility in a tropical semi-arid soil under long-term cultivation. Bio Fertil Soils 2003 37 83-89. 

Boawn L.C., Viets F.G. Jr., Crawford C.L. Plant utilization of zinc from various types of zinc compounds and fertilizer materials. Soil Sci 1957 83 219-227. 

Lee K.W., Keeney D.R. Cadmium and zinc additions to Wisconsin soils by commercial fertilizers and wastewater sludge application. Water Air Soil Pollut 1975 5 109-112. 

Ohya H, Komai Y, Yamaguchi M (1985) Zinc effects on soil microflora and glucose metabolites in soil amended with 14C-glucose. Biol Fertil Soils 1 117-122... 

In echinoderms, zinc concentrations are usually higher in detrital feeders than in carnivores, higher in surface feeders than in sediment feeders, and higher in specimens collected inshore than those collected offshore in deeper waters (Eisler 1980). Sea cucumbers, Stichopus tremulus, accumulate radiozinc-65 from seawater by a factor of 1400 however, radiozinc accumulation data should be viewed with caution because addition of stable zinc can reduce zinc-65 accumulations in echinoderm viscera up to tenfold (Eisler 1981). Zinc inhibits the formation of the fertilization membrane in sea urchin eggs, possibly by interfering with cortical granule-derived proteases and proteins (Nakamura et al. 1989). 

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