Steel industry waste treatment

Environmental Uses. Next to steel fluxing, environmental uses of lime are the biggest market, accounting for 24% of total lime consumption. These uses include air pollution control, water, sewage, and industrial wastewater treatment, hazardous waste treatment, etc. 

Treatment of Industrial Wastes. The alkaline nature and inexpensive price of lime make it ideal for treatment of acid waste Hquors (6), including waste pickle Hquids from steel plants, wastes from metal plating operations, eg, chrome and copper plating, acid wastes from chemical and explosives plants, and acid mine wastewaters. 

O Waste Treatment in the Iron and Steel Manufacturing Industry... 

In most countries, solid waste containing metals such as neutralization sludge from the plating industry and flue dust from the metal and steel industries is currently collected and dumped in landfill, where it constitutes a perpetual toxic threat to the environment and a waste of resources. The alternatives to this landfill disposal are either to reduce the rate of discharge at source by an individually designed recovery process or to separate and recover the metals from the collected waste in a centrally located facility. A presumption for a centrally located facility would be that companies with metals in their effluents require treatment of their total wastewater streams. This could be accomplished through the relatively simple process of neutralization, which requires minor investment in sedimentation tanks and dewatering equipment and involves relatively modest operation costs. 

Land disturbance and exposure of buried geologic strata to the open environment leads to sulfide oxidation (if present) and, as a consequence, water-quality degradation of runoff. For water-quality-control purposes, sedimentation ponds required by law are used as water treatment basins. Often, the pH of such basin waters is below 6, and the concentration of heavy metals is above acceptable levels. Water treatments include neutralization and removal of heavy metals as precipitates. Similar water-quality problems arise from other industrial sources, including heavy steel industries, electronics, food processing, mineral processing, and waste-disposal leachates. This portion of the chapter deals with some of the chemical agents used for neutralization purposes and some of their limitations. 

Co. Ltd (SPR) was founded to recycle the waste plastics collected in Sapporo city, where 13 500 t has been baled every year. This system has received excellent support by Sapporo city. However, only half of the baled plastics is used in the SPR liquefaction plant located just next to the baling plant due to the tender system controlled by JCPRA. Thus, the operating ratio of the SPR plant is not so high, and this also raises the treatment cost of waste plastics, as does the small scale. The remaining half is used for the iron and steel industry, far from Sapporo. The third liquefaction plant constructed at Mikasa city, Hokkaido stopped this March, since sufficient raw plastic waste could not be obtained. 

Reverse Osmosis-Based Treatment of Radioactive Liquid Wastes Generated in Hospital Facility and in Steel Industry Case Studies... 

Many of these uses are very significant since they are described from the point of extensive commercial experience. This is particularly true of the food, medical, and waste treatment fields. For example, cheese whey solids that previously were pollution problems are recovered now at the rate of several hundred tons/day and sold as valuable food. Similarly the recent advances of hemofiltration over hemodialysis are improving the quality of life for thousands of patients who suffer from renal failure. Also pollution abatement by ultra- and hyperfiltration in the pulp, textile, and steel-processing industries is now a commercial reality for certain types of waste streams. 

Industrial applications of diffusion dialysis for acid recovery include recovery of acids from waste acid from surface treatment of steel and stainless steel, from alumilite treatment, from the etching process of aluminum and titanium, and in other hydrometallurgy industries. The recovery rate of acid can be controlled by changing the flow velocity of the waste solution and water in the dialyzer, in which solutions flow counter-current. For hydrochloric acid, as explained before,... 

M. Sancho, J.M. Amal, G. Veidu, J. Lora, Reverse osmosis-based treatment of radioactive liquid wastes generated in hospital facility and steel industry Case studies, in A.K. Pabby, S.S.H. Rizvi, A.M. Sastre (eds.). Handbook of Membrane Separations Chemical, Pharmaceutical, and Biotechnological Applications, CRC Press, Boca Raton, EL, 2008, Chapter 32, pp. 919-931. 

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