Raffinate solution

Lube oil extraction plants often use phenol as solvent. Phenol is used because of its solvent power with a wide range of feed stocks and its ease of recovery. Phenol preferentially dissolves aromatic-type hydrocarbons from the feed stock and improves its oxidation stability and to some extent its color. Phenol extraction can be used over the entire viscosity range of lube distillates and deasphalted oils. The phenol solvent extraction separation is primarily by molecular type or composition. In order to accomplish a separation by solvent extraction, it is necessary that two liquid phases be present. In phenol solvent extraction of lubricating oils these two phases are an oil-rich phase and a phenol-rich phase. Tne oil-rich phase or raffinate solution consists of the "treated" oil from which undesirable naphthenic and aromatic components have been removed plus some dissolved phenol. The phenol-rich phase or extract solution consists mainly of the bulk of the phenol plus the undesirable components removed from the oil feed. The oil materials remaining... 

Spectrophotometric methods for determining concentration of Pu(111, IV, VI, and "polymer") in nitrate media have been reported.(30) Adaptation of such procedures to routine rapid in-line analysis of feed and raffinate solutions may be possible. 

The secondary flue dust from the converter, containing mainly zinc and lead, is leached with the ammoniacal raffinate solution from the Cu/Ni extraction. Lead is left in the residue. Finally, zinc carbonate is precipitated by addition of CO2 followed by thermal stripping of ammonia. The zinc carbonate is calcined to zinc oxide and ammonia is recycled to leaching. 

This dewaxing process is always installed in combination with Edeleanu solvent extraction because recovery of the solvents from the preceding step is not required. For example, if dewaxing follows the refining operation, the raffinate solution is taken directly from the extraction unit and the solvent composition is adjusted to that used for dewaxing by the addition of a benzene-rich solvent which is readily recovered from the dewaxed oil solution because of the wide difference in boiling points of the solvents. 

Chlorine Residual Extraction. A 400-mL solution of distilled water containing 70 ppm of sodium bicarbonate, 120 ppm of calcium sulfate, and 47 ppm of calcium chloride was extracted under typical operational conditions. Similarly, a solution containing all of these materials plus a 2-ppm chlorine residual (prepared with NaOCl) was extracted. Analysis of the U-tube traps, feedstock, and raffinate solutions in each case (blank and chlorine residual samples) showed that no new chlorinated compounds were formed by the presence of a chlorine residual. 

The effectiveness of the separation can be quantified by an efficiency, q, which is defined as the actual increase in raffinate concentration divided by the increase expected from the altered solution volume. For example, if half of the feed solution is absorbed by the gel and the raffinate has twice the feed concentration, then the efficiency would be 100%. The efficiency is primarily a measure of how well the solute is excluded from the polymer network of the geL The efficiency can be reduced, however, by physical entrainment of raffinate solution around the gel particles. The entrained solute can be recovered by washing the swollen gel and adding the wash liquor to new feed. 

First, as a once-through process, which lasted 8 hours and gave far better yields for the An(III) recovery than the hot test performed in 1999 with nPr-BTP. More than 99.9% of Am(III) and more than 99.8% of Cm(III) were recovered from the genuine feed. An(III) losses in the raffinate solution and in the spent solvent, reached respectively 180 and 13 pg/L for Am(III) and 23 and 1 pg/L for Cm(III). A mean DF of 150 was estimated for An(III) versus Ln(III), but higher values were calculated for lighter Ln(III), which were also the major components initially present in the feed. Hence, the... 

Furthermore, acetone, which remains dissolved in the raffinate solution after extraction, may be distilled readily therefrom because of its high volatility from aqueous solutions and particularly from the solution with its high concentration of solute. This high concentration greatly reduces the vapor pressure of water, and for the same reason, acetone can be evaporated or distilled readily from the extract layer. In fact, a substantial portion of that used as the solvent for the acetic acid can be evaporated from the extract layer in a simple pot still without distilling over an appreciable amount of acetic acid. 

Fluoride containment still has to be considered in the operation of this process, as with sulfuric acid acidulation, since the acid treatment similarly mobilizes chemically bound fluoride. Problems from this source are minimized by prior calcination of the feed phosphate rock, as has been practiced for the early Japanese experimental operations using this process. In any case, fluoride tends to follow the aqueous phase throughout to end up as a component of the calcium chloride raffinate solution. From this stream, fluoride may either be recovered for sale or removed from the calcium chloride stream and discarded by methods which have been discussed (Section 10.4.4.). 

Recovery of Metals Concentrate. The Sc-depleted raffmate from the ion exchange process step contains the two major constituents, Fe and Mn, in their divalent state, and other transition and rare metals in small amounts. The recovery of these metals in the presence of large amounts of Fe and Mn is done effectively by selective precipitation in the pH range between 6.5 and 7.5. In this experiment, the pH of the raffinate solution was adjusted with ammonium hydroxide to 7.4, and the resulting precipitate washed and dried. It contains the metals listed in Table VIII in a mattix of hydrated ferric oxide the precipitation of appreciable amounts of iron, about 14% of the iron content of the raffinate, is primarily due to the partial oxidation of the ferrous... 

In the mixer of the ideal stage, equilibrium is established, so that the two-phase mixture M produces extract and raffinate solutions E and R, the products of the operation, located on opposite ends of the tie line through M. The compositions of the streams E and R must be determined graphically on the diagram (which may involve trial-and-error tie-line interpolation). Their weights may be computed either graphically,... 

Solvent Recovery. Although not strictly part of the extraction operation, all such separations are ordinarily followed by removal of solvent from the extract and raffinate solutions to give the finished products. Figure 6.5 shows a typical extraction solvent recovery scheme. Distillation is... 

In the simplified case, feed and finished extract and raffinate solutions are B-free, and pure B is the extracting solvent. Refer to Fig. 

Stages / + 1 through n constitute the raffinate stripping section of the cascade, where the raffinate solution is exhausted of its C content. The primary raffinate product Rn is divided into two streams Pr, the saturated raffinate product, may be further treated to remove solvent and to provide the finished raffinate and operation not concerned with the extraction operation and which when mixed with the extracting solvent S, provides the raflSnate reflux Pn, Bn, and Pr are of the same composi-... 

Only a minor part of the total equipment in a solvent treating plant is devoted to the extraction operation. Elaborate equipment is required to distill the solvent (or oil) from the extract and raffinate solutions, to separate the last traces of solvent from the finished oils, and finally to recover... 

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