Separator coagulation

Particle and colloidal stability, that is, lack of sedimoitation, stratification or phase separation, coagulation or flocculation, or changes in viscosity when the latex is stored, shipped, pumped, sprayed, formulated, etc. is required for most end-uses of acrylic and styrene-acrylic latexes. Such stability is primarily determined by the type and level of surfactants or other stabilizers and specialty or auxiliary monomers used. The trade-off is that functional materials contributing to particle and colloidal stability generally also increase water or moisture sensitivity, and there is an optimum balance for each end-use application. 

Refinery High COD. Contains oil, phenols, ammonia, sulphides, cyanide, thiocyanate API separator, coagulation and flocculation, and DAF Polyamine followed by anionic or cationic polyacrylamide... 

The repulsion between two double layers is important in determining the stability of colloidal particles against coagulation and in setting the thickness of a soap film (see Section VI-5B). The situation for two planar surfaces, separated by a distance 2d, is illustrated in Fig. V-4, where two versus x curves are shown along with the actual potential. 

Pretreatment of Suspensions. Another important aspect of soHd—Hquid separation is conditioning or pretreatment of the feed suspension to alter some important property of the suspension and improve the performance of a separator that follows. A conditioning effect is obtained using several processes such as coagulation and docculation, addition of inert filter aids, crystalliza tion, freezing, temperature or pH adjustment, thermal treatment, and aging. The first two operations are considered in more detail due to their importance and wide use. 

The cake produced by the digestion is extracted with cold water and possibly with some diluted acids from the subsequent processes. During the cake dissolution it is necessary to maintain the temperature close to 65°C, the temperature of iron sulfate maximum solubiUty. To prevent the reoxidation of the Fe " ions during processing, a small amount of Ti " is prepared in the system by the Ti reduction. The titanium extract, a solution of titanium oxo-sulfate, iron sulfate, and sulfuric acid, is filtered off. Coagulation agents are usually added to the extract to faciUtate the separation of insoluble sludge. 

P perApplications. In beater additions, the latex is mixed with the beaten paper pulp either by addition at the beater or to the stock chest at the wet end of the paper machine. In either case, the pH of the pulp is reduced to 4.0—4.5, usually by the addition of a solution of alum to the pulp—latex mixture which has been thoroughly agitated. The latex, which for this appHcation must be based on an anionic emulsifier, coagulates as the pH drops. The latex soHds separate ia intimate associatioa with the pulp fibers. The pulp is thea screeaed and the paper web formed ia the coaveatioaal way. A latex for this purpose must possess the proper balance between mechanical and chemical stabiHty. 

Tofu. Tofu is prepared by adding a coagulant such as calcium sulfate to soymilk to precipitate the protein and oil into a gelatinous curd. The curd is then separated from the soluble portion (whey), pressed, and washed to yield a market-ready product. Tofu, a traditional food in Japan (90), was populari2ed in the United States in the late 1970s and is available in many U.S. supermarkets. 

Emulsified oil contains a Hquid film so that it will not separate by gravity without first breaking the emulsion. This is achieved by adding surfactants, emulsion breaking polymers or coagulants. After the emulsion is broken, the conventional technologies described above are appHcable. 

The intrinsic and extrinsic system paths advance independendy through their initial interactions but eventually follow a common course. The activity of both pathways are important m vivo. The concept of separate systems provides a practical means of evaluating laboratory and clinical coagulation abnormalities. 

Samples may separate into two or more phases as they cool in the sample line precipitate, coagulate, and freeze. Laboratory sampling may result in nonrepresentative compositions. Heat tracing may be required and may not be installed on the nonroutine sample locations. 

As both layers are blaek and the interface is not easy to distinguish, careful separation is necessary. In addition, black amorphous material forms at the interface, making the separation difficult. It can be coagulated by standing or removed by filtration. 

Oil Expressed as oil or chloroform extractable matter, ppmw Scale, sludge and foaming in boilers impedes heat exchange undesirable In most processes Baffle separators, strainers, coagulation and filtration, diatomaceous earth filtration... 

At the pH = Jt there is a balance of charge and there is no migration in an electric field. This is referred to as the isoelectric point and is determined by the relative dissociation constants of the acidic and basic side groups and does not necessarily correspond to neutrality on the pH scale. The isoelectric point for casein is about pH = 4.6 and at this point colloidal stability is at a minimum. This fact is utilised in the acid coagulation techniques for separating casein from skimmed milk. 

The alkaline filtrate and washings are combined and partially neutralized by the addition of 150-175 ml. of concentrated hydrochloric acid. Sufficient sodium sulfide solution is added to precipitate all the lead ion present (Note 6). The suspension is brought to a gentle boil to coagulate the lead sulfide, allowed to cool somewhat, and filtered with suction. The filtrate is placed in a 2-1. beaker set in an ice bath and acidified Caution in the hood) with about 150 ml. of concentrated hydrochloric acid to precipitate crude 2-hydroxyisophthalic acid monohydrate (Note 7). The suspension is cooled to 0-5° and filtered to separate the crude acid, which weighs 35-49 g. after being dried in a vacuum oven at 110°/50-150 mm. for 5 hours (Note 8). 

Points of Chemical Addition In independent physical-chemical treatment or in phosphate removal in the primary clarifier ahead of biological treatment, chemicals are added to raw sewage. In tertiary treatment for phosphate removal and suspended solids (SS) reduction, they are added to secondary effluent. In both cases, proper mixing and flocculation units are needed. For phosphate removal or improvement of SS capmre in biological secondary treatment, chemicals are often added directly to aeration units or prior to secondary settling units, without separate mixing and flocculation. In some phosphate removal applications coagulants are added at... 

Technology Description To achieve precipitation, acid or base is added to a solution to adjust the pH to a point where the constituents to be removed have their lowest solubility. Chemical precipitation facilitates the removal of dissolved metals from aqueous wastes. Metals may be precipitated from solutions as hydroxides, sulfides, carbonates, or other soluble salts. A comparison of precipitation reagents is presented in Table 7. Solid separation is effected by standard flocculation/ coagulation techniques. 

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