Viscose industry

Carbon disulphide control of exposure m the viscose industry Man-made mineral fibres... 

The hazards of chemicals are commonly detected in the workplace first, because exposure levels there are higher than in the general environment. In addition, the exposed population is well known, which allows early detection of the association between deleterious health effects and the exposure. The toxic effects of some chemicals, such as mercury compounds and soot, have been known already for centuries. Already at the end of the eighteenth century, small boys who were employed to climb up the inside of chimneys to clean them suffered from a cancer of the scrotum due to exposure to soot. This was the first occupational cancer ever identified. In the viscose industry, exposure to carbon disulfide was already known to cause psychoses among exposed workers during the nineteenth century. As late as the 1970s, vinyl chloride was found to induce angiosarcoma of the liver, a tumor that was practically unknown in ocher instances. ... 

Cotton linters or wood pulp, usually in the form of sheets, is steeped in strong alkali (18-50%). The swollen sheets are then pressed to force out most of the excess alkali solution. This alkali cellulose is then shredded, and aged if low viscosity is desired. The aging process is the one followed in the viscose industry and is fully explained in any discussion of that process. More alkali may be introduced during the shredding, either as a concentrated solution or as solid alkali.18 The alkali... 

Applications Carbon disulfide is mainly used in the viscose industry for fiber production. Smaller quantities are utilized in the manufacture of cellophane from viscose or as a starting material in the production of carbon tetrachloride. In addition carbon disulfide is used in the production of vulcanization accelerators, flotation agents, corrosion inhibitors, pesticides and intermediates for pharmaceuticals. 

Drexler H, Goen T, Angerer J., et al. 1994. Carbon disulfide. 1. External and internal exposure to carbon disulphide of workers in the viscose industry. Int Arch Occup Environ Health 65 359-365. 

Abstract. Carbon disulfide is a well-known occupational hazard in viscose industry. This study was focused on assessment of the external and internal exposure to carbon disulfide of occupationally exposed workers with a view to make a comparative analysis of the results and determine the correlation ratio between amounts of carbon disulfide introduced in human organism and amounts that are kept there. These studies are a basis for further identification of methods to protect the workers against the hazardous effect of carbon disulfide as a chemical factor of the workplace. 

Carbon disulfide is widely used in production of rayon, carbon tetrachloride, rubber chemicals and cellulose film, and is a by-product of widely used dithiocarbamate pesticides. Chronic low level and long term exposure to CS2 can cause eye, ear, cardiovascular, nervous system and reproductive effects (Tan et al., 2001), (WHO Criteria 10, 1979), (Kaloyanova, 1981). There are scientific reports that the long term exposure to low concentrations of CS2 is related to endocrine disturbances as well (Lancranian I. et al., 1972) (Lyubomirova K. et al., 2006). Carbon disulfide is mostly used in viscose industry to yield sodium cellulose xanthate from alkali cellulose. (Tan et al., 2001). 

DDRM is particularly useful for the binary polymer blends. The dynamic interfacial tension coefficient, Vj2, is determined from the time evolution of a distorted fluid drop toward its equilibrium form. Measurements of either low viscosity model systems or high viscosity industrial polymer mixtures led to a good agreement with values obtained from the widely used breaking thread method. DDRM enables to measure in polymeric blends of commercial interest — the high viscosity systems that frequently are impossible to characterize by other techniques. Furthermore, for the first time it is possible to follow the time dependence of Vj, thus unambiguously determine its dynamic and equilibrium values. 

Table 22.1.11. Waste gas in the viscose industry (After reference 35)...

Needlefelts are not as widely used in liquid filtration as they are in dust collection. Unless required for depth straining, as in the viscose industry, or unless the particles can be restricted to the surface as in some filter belt mining applications, the risk of premature blinding through pore blockage is always a threat. 

EH 44 Dust in the workplace general principles of protection EH 45 Carbon disulphide control of exposure in the viscose industry... 

In my book, Process Design for Reliable Operations, I ve given a vivid example of the terrible consequences of placing high-viscosity industrial fuel oil on the tube side of a water cooled exchanger. 

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