<p>At treatment of wastewater of viscose rayon's spinning produces the sediment – zinc-bearing sludge, a humidity content of 66 to 95 %. To date, it is deposited up to 2.5 million cubic meters of zinc-bearing sludge in the ponds of plants in Russia. In the paper chemical composition and particle size distribution of sludge of viscose rayon manufacturing (OJSC "Balakovskoye khimvolokno", OJSC "Ryazanskoye khimvolokno", OJSC "Sibvolokno") are presented. The percentage of zinc in sludge is of 6 to

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... 23 %. Investigations by methods of X-ray diffraction (XRD) and scanning electron microscopy (SEM) are shown, that zinc is present in form of hydroxides, carbonates and silicates. Thermodynamic analysis of zinc dissolution of compounds, found in product of sludge roasting at a temperature of 850ºС, was conducted.</p>