Acid waste

Petroleum. Apart from its use ia petrochemicals manufacture, there are a number of small, scattered uses of lime ia petroleum (qv) production. These are ia making red lime (drilling) muds, calcium-based lubricating grease, neutralization of organic sulfur compounds and waste acid effluents, water treatment ia water flooding (secondary oil recovery), and use of lime and pozzolans for cementing very deep oil wells. 

Acetic anhydride and acetic acid increase the solubiUty of the two phases in each other, and they are employed for the commercial N-nitration of hexamethylenetetramine [100-97-0] (11) to form cyclotrimethylenetrinitramine [121-82-4] (RDX), (CH2)3(NN02)3. Renewed consideration has been given to replacing H2SO4 with an improved soHd catalyst to reduce the environmental problems of disposal or reconcentration of the waste acid and to increase production of desired nitrated isomers. For example, a catalyst with suitable pore size might increase the production of 4-MNT and reduce that of 3-MNT when toluene is nitrated. 

The objective is to so operate that most of the HNO reacts within the reactor, and the resulting used acid is mainly a mixture of H2SO4 and water. In some processes, 99% or more of the feed HNO reacts. Dispersions (or mixtures) of such a waste acid and the nitration product are relatively safe to handle. 

A significant concern in all nitration plants using mixed acids centers on the disposal method or use for the waste acids. They are sometimes employed for production of superphosphate ferti1i2ers. Processes have also been developed to reconcentrate and recycle the acid. The waste acid is frequently first stripped with steam to remove unreacted HNO and NO. Water is then removed by low pressure evapori2ation or vacuum distillation. 

The resulting acid can often be concentrated to 93—96% H2SO4 at the nitration plant. When the waste acid contains large amounts of dissolved organics, as occurs in a few nitration plants, the acid is then often converted at high temperatures, in the presence of air, to mainly SO2 plus carbon oxides. The SO2 is then oxidi2ed to SO and converted back to concentrated H2SO4. 

Example Fractionation of Fatty Acids. A mixture of waste acids from a vegetable oil refinery are to be separated into five fractions as shown in Table 1. 

Dihydroxyanthraquinone. This anthraquinone, also known as quinizarin [81-64-1] (29), is of great importance in manufacturing disperse, acid, and vat dyes. It is manufactured by condensation of phthalic anhydride (27) with 4-chlorophenol [106-48-9] (28) in oleum in the presence of boric acid or boron trifluoride (40,41). Improved processes for reducing waste acid have been reported (42), and yield is around 80% on the basis of 4-chlorophenol. 

Technology Description Neutralization is a process used to treat acids or alkalis (bases) in order to reduce their reactivity or corrosiveness. Neutralization can be an inexpensive treatment if waste alkali can be used to treat waste acid and vice versa. Typical neutralizing reagents include ... 

Applicability/Limitations Liquid injection incineration can be applied to all pumpable organic wastes including wastes with high moisture content. Care must be taken in matching waste (especially viscosity and solids content) to specific nozzle design. Particle size is a relevant consideration so that the wastes do not clog the nozzle. Emission control systems will probably be required for wastes with ash content above 0.5 percent (particulate control) or for halogenated wastes (acid gas scrubbers). 

Service company wastes such as empty drums, drum rinsate, vacuum truck rinsate, sandblast media, spent solvents, spilled chemicals, and waste acids... 

It also involves wastewater streams containing unreacted material and by-products, waste acids, decompn products and extracted impurities, and exhausted reagents. These wastewater streams, if untreated, constitute major pollution nmblems... 

Spent pickle liquor is considered a hazardous waste (K062) because it contains considerable residual acidity and high concentrations of dissolved iron salts. For example, spent pickle liquor and waste acid from the production of stainless steel is considered hazardous. The hazardous constituents in K062 are lead, nickel, and hexavalent chromium. Waste pickle liquor sludge generated by lime stabilization of spent pickle liquor is not considered hazardous unless it exhibits one or more of the characteristics of hazardous waste. An estimated 6 million tons of spent pickle liquor are generated annually in the U.S.1... 

The spent pickling liquor is called waste pickling liquor (WPL), which must be properly treated for disposal or reuse. Wastewaters from pickling include acidic rinse waters, metallic salts, and waste acid. WPL is considered a hazardous waste by the U.S. Environmental Protection Agency (U.S. EPA). 

The obvious chemicals to use are any available waste acids or bases. When these are not present or inadequate, the best acidic choice is concentrated sulfuric acid (66° Baume). It can be stored at this concentration in a carbon-steel vessel. It is less corrosive, less costly, and less likely to produce atmospheric pollution than its nearest competitor, hydrochloric acid. 

Lantagne and Velin [267] have reviewed the application of dialysis, electrodialysis and membrane cell electrolysis for the recovery of waste acids. Because of the new trends governed by environmental pressures, conventional treatment methods based on neutralization and disposal are being questioned. Membrane and electromembrane technologies are considered to be potential energy-efficient substitutes for conventional approaches. Paper mills will focus on the application of ion-exchange membranes namely dialysis, electrodialysis and membrane cell electrolysis for recovery of waste acids. 

Lantagne G, Velin AP, Overview of the application of dialysis, electrodialysis and membrane cell electrolysis for the recovery of waste acids, in ref (45a), and references therein... 

Mani KN (1988) Proc-APCA Annu Meet 1988, 81st (1) Paper 88/6A 7, Aquateck membrane technology for regeneration of hazardous waste/acid effluent streams Chem Abstr 110 (1989)... 

Novel ion-exchange technology has recently been developed for purification of brine. Different resins have been developed for removal of sulphate impurities as well as calcium and magnesium hardness. The process is very simple and since only water is consumed to regenerate the ion-exchange resins, the operating costs are extremely low. The equipment, which is similar to that currently widely utilised for purification of waste acid, is very compact. It is expected that commercial-scale systems of both types will be installed later in 2000. 

The composition of industrial wastes varies depending on the industrial structure of a country or region. It consists of general rubbish, packaging, food wastes, acids, alkalis, oils, solvents, resins, paints, mine spoils and sludges. A proportion of the industrial waste is classified as hazardous waste because it contains materials that are presently or potentially hazardous to humans and other living organisms. 

Ludwigshafen, Germany. BASF generated the ionic liquid in situ, to remove waste acidic hydrogen chloride. The key reaction involved is of a well-known generic type ... 

T0860 Viatec Recovery Systems, Inc., Waste Acid Detoxification and Reclamation... 

T0783 Terrapure Systems, L.L.C., Palladized Iron Remediation Technology T0860 Viatec Recovery Systems, Inc., Waste Acid Detoxification and Reclamation T0862 Vortec Corporation, Cyclone Melting System (CMS)... 

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