Separating, manufacturing process

Figure 3. Generalized process for lithium-ion separator manufacturing. Each step of the separator manufacturing process has online detection systems to monitor the quality of the separator.

Fig. 20.3 (a) Polyolefin separators used in Li-Ion batteries, (b) A simplified flowchart for separator manufacturing process. Each step of the separator manufacturing process has online detection systems to monitor the quality of the separator. Reprinted with permission from Chem. Rev. 104 (2004) 4419-4462, copyright (2(X)4), American Chemiceil Society... 

Hydrazine forms a high (120.5°C) boiling azeotrope with water that has a composition of 58.5 mol % (71.48 wt %) N2H4 at 102.6 kPa (1.02 atm) pressure. This comphcates the separation of hydrazine from water in the manufacturing process because it necessitates the removal of a large amount of water in order to approach the azeotropic composition. 

The dominant commercial form of elemental phosphoms is the a-white aHotrope. a-White phosphoms is often designated simply as because the soHd consists of tetrahedral P molecules. In its pure form, it is a white soHd that forms a clear Hquid when melted. However, the commercial product is generally somewhat yellow, both as a soHd and as a Hquid, owing to the presence of small amounts of a ted phosphoms aHotrope. Commercial white phosphoms may also be slightly gray in color because of incomplete separation of coke dusts and other impurities generated in the manufacturing process. 

It is very difficult to treat MDA as a single entity because the manufacturing processes of PMDA and MDA are essentially identical, with the exception of a separation step. This article focuses on the technology of 4,4 -MDA, and it also includes properties of isomers and oligomeric mixtures when they are of commercial importance. The 4,4 -MDA is a suspected human carcinogen, and therefore special handling of this material is required. AH of the MDA and PMDA produced is consumed in industries that are "destmctive" of MDA s chemical identity. Thus MDA loses its unique chemical identity and is not encountered by household consumers. 

There are four principal steps in bromine production (/) oxidation of bromide to bromine (2) stripping bromine from the aqueous solution (3) separation of bromine from the vapor and (4) purification of the bromine. Most of the differences between the various bromine manufacturing processes are in the stripping step. 

Modem manufacturing processes quench the roast by continuous discharge into the leach water held in tanks equipped with agitators. At this point the pH of the leach solution is adjusted to between 8 and 9 to precipitate aluminum and siHcon. The modem leaching operations are very rapid because no or htde lime is used. After separation of the ore residue and precipitated impurities using rotary vacuum filters, the cmde Hquid sodium chromate may need to be treated to remove vanadium, if present, in a separate operation. The ore residue and precipitants are either recycled or treated to reduce hexavalent chromium to Cr(III) before disposal. 

Manufacturing Processing and Uses. In commercial production, aqueous urea solution is mixed with acetaldehyde in 1 1 molar ratios. An acid catalyst is introduced into the reaction mixture which is staged at various process temperatures. After neutralization with a base, the CDU is separated from the mother hquor by filtration or spray drying. 

The cmde diatomite, which may contain up to 60% moisture, is first milled in a method that preserves the intricate stmcture of the diatomite. This material is fed to dryers operating at relatively low temperatures, where virtually all of the moisture is removed (see Drying). Coarse and gritty nondiatomaceous earth material is removed in separators and preliminary particle si2e separation is made in cyclones. For many producers, all of the manufacturing processes, with the exception of the calcination step, take place while the material is being pneumatically conveyed. The resultant material is termed natural product. This is the only type of diatomite made by some producers. 

An auxiliary facility is one that supports another facility s activities (e.g., research and deveiopment iaboratories, warehouses, storage facilities, and waste-treatment facilities). An auxiliary facility can take on the SIC code of another covered facility if its primary function is to service that other covered facility s operations. Thus, a separate warehouse facility (i.e., one not located within the physical boundries of a covered facility) may become a covered facility because it services a facility in SIC codes 20-39. Auxiliary facilities that are in SIC codes 20-39 are required to report it they meet the employee criterion and chemical thresholds for manufacture, process, or use. Auxiliary establishments that are part of a multi-establishment facility must be factored into threshold determinations for the facility as a whole. 

The term manufacture also includes coincidental production of a toxic chemical (e.g., as a byproduct or impurity) as a result of the manufacture, processing, use, or treatment of other chemical substances. In the case of coincidental production of an impurity (i.e., a chemical that remains in the product that is distributed in commerce), the de minimis limitation, discussed on page 11, applies. The de minimis limitation does not apply to byproducts (e.g., a chemical that is separated from a process stream and further processed or disposed). Certain listed toxic chemicals may be manufactured as a result of wastewater treatment or other treatment processes. For example, neutralization of acid wastewater can result in the coincidental manufacture of ammonium nitrate (solution). 

Section 313 reporting Is required If threshold quantities are exceeded. The thresholds vary depending upon the year for which the report Is submitted and separate thresholds apply to the amount of the chemical that is manufactured, processed, or otherwise used. 

Do not add together the quantities of the chemical that are manufactured, processed, and used at yourfacllity, because each of these activities requires a separate threshold determination. For example, if in 1989 you processed 20,000 pounds of a chemical and you otherwise used 6,000 pounds of that same chemical, your facility has not met or exceeded any applicable threshold and thus is not required to report for that chemical. 

If sulfuric acid was manufactured, processed, or otherwise used at the battery plant in amounts that exceed the applicabie thresholds, you would be required to report releases of sulfuric acid separately. Similarly, releases of lead and lead com-... 

The development of electrostatic precipitators soon led to new applications, including the separation of metal oxide fumes. This was followed by various metal manufacturing processes such as the lead blast furnace, ore roaster, and reverberatory furnace. Electrostatic gas cleaning was soon applied also in cement kilns and in several exotic applications, such as recovering valuable metals from exhaust gases. 

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