Solvent-slurry extractions

THF Conversion. Tetrahydrofuran (THF) conversion was calculated from the difference between the initial and the final solubilities of the total coal-solvent slurry in THF. It was assumed that all of the solvent and none of the starting coal was soluble in THF. THF conversions were calculated on an MAF coal basis and adjusted for the coal not recovered from the autoclaves. The filter cake resulting from filtration of the product at 250 C was continuously extracted with THF for up to 3 days. 

ENSR International Group soil cleaning process is an ex situ treatment for soils contaminated with petroleum hydrocarbons. The process uses a combination of soil washing and solvent extraction. Soil washing removes heavy metals and hydrocarbons from coarse soil particles, resulting in a reduced volume of material to be treated by solvent extraction. Solvent extraction uses a chemical additive that enhances the extraction of hydrocarbons from soil particles in an aqueous slurry. 

Soils containing more than 10% water can cause the soil/solvent slurry to form emulsions and either agglomerate or coat the walls of the process vessels. As a result, the solvents do not adequately contact the soil for effective contaminant extraction. The vendor claims to have solved this problem by adding a small amount of a proprietary reagent to the soil in the initial process step. 

The most common method for the separation and concentration of flavor chemicals before chromatography is solvent extraction. If the aroma active components in a sample are less than a microgram/liter then solvent extraction followed by fractional distillation can be used to concentrate the analytes above 1 4g/liter. This is done for two reasons (1) to remove the odorants from some of the interfering substances and nonvolatiles, and (2) to concentrate the sample for greater sensitivity. The choice of solvent(s) depends on a number of issues, but similar results can be obtained with many solvents. Table Gl.1.2 lists a number of solvents, their polarity, and physical properties. Pentane is the least polar and ethyl acetate the most. The sample must be an aqueous or dilute sample, dissolved or slurried into water to a final concentration of 80% to 90% water. Dilute aqueous samples will present the greatest polarity difference between the solvent and the sample, driving more volatiles into the extracting solvent. 

Preserving soil with methanol is the most efficient way to arrest bacterial activity and to prevent VOC volatilization. Methanol is also a much more efficient extraction solvent than water, and VOC concentration data obtained from the methanol-preserved samples are higher in values than the data obtained from soil/water slurries of the same samples (Vitale, 1999). 

The X-M process combines solvent extraction and milling of the rice (41). Brown rice is pretreated with warm rice oil (0.5%) for 2-3 hours to soften the bran. The rice is then milled in the presence of a rice oil miscella. The solvent slurry is then removed from the rice and the rice oil is recovered. Advantages are that stabilization is not required and the resultant oil had a minimum FFA level. This process is no longer used. 

Sterol Analyses. The overall analytical procedure for each 2 cm subcore section Is schematically represented in Figure 3, After homogenization and lyophilization, approximately 1 g of each sediment was mixed with 37.5 ml of chloroform, 75 ml of methanol and 30 ml of a buffered aqueous solution (pH=7). The sediment-solvent slurry was then sonicated for 3-5 minutes and the extract decanted to a separatory funnel. Seventy five ml of water was then added to the funnel, resulting In separate aqueous and organic phases. The chloroform layer was then removed and the aqueous phase washed five times with chloroform. The chloroform fractions were then combined and the volume reduced to 10 ml under nitrogen at 37°C. The entire extraction was repeated until the chloroform phase was visually colorless (6-9 extractions). 

In a typical experiment, 4 kg of fresh, locally grown pumpkins (variety Connecticut field) were homogenized with 2 L of water and this slurry was placed in a 12 L three-necked flask. The sample was heated at reflux for 3 hours using a modified Likens-Nickerson distillation head (IB). The distillation was performed at atmospheric pressure and diethyl ether was used as the extracting solvent. The ethereal concentrate was dried over anhydrous sodium sulfate, filtered and concentrated using a low hold-up distillation column by the usual procedure. 

After agitation of the aqueous slurry with the extraction solvent, the two liquid phases may be separated The cell debris remains in the aqueous phase while the poly(/3-hydroxy butyric acid) is dissolved in the solvent phase. Suitable non aqueous solvents can be chloroform, 1,2-dichloroethane, and methylene chloride (6,9). 

PFE procedures for the soil were carried out in an Accelerated Solvent Extractor (ASE, Dionex Corporation, Salt Lake City, Utah). The extraction method was optimized by varying extraction temperature and number of extraction cycles. The extraction solvent was acetonitrilermethanol (1 1, v v) and the pressure was kept constant at 1500 psi, which in previous studies pressure did not show a big influence on the extraction efficiency (13), The soil used for optimization was of the Helemano series (14), spiked in the laboratory by the organic solvent slurry method (15) at approximately 3 pg/g for each of the analytes. After extraction, the sanq)les were filtered through sodium sulfate and 0.2 pm nylon filter and concentrated with a gentle flow of nitrogen gas before GC-MS analysis. 

Static Vacuum SDE. Washed, de-stoned cherry flesh (100 g) was blended with 100 ml of deionised water. A 100 ml sample of this fruit slurry was transferred to the sample flask of a static vacuum SDE apparatus, as described by Maignial et al (10). Iso-octane (2.5 ml) was used as the extracting solvent. The temperature of the sample and solvent heating waters was 38°C and 22°C, respectively ( 2°C). The cooling mixture was a 1 3 ethylene glycoliwater mix and was maintained at -5°C ( 1°C) by a chilling unit. After extraction, the solvent extract was concentrated to 500 pi using a rotary evaporator. 

Extraction solvent concentrated in heavy metals purified water or slurry... 

Pollution Prevention. Procedures haven been developed for recovery of composite ammonium perchlorate propellant from rocket motors, and the treatment of scrap and recovered propellant to reclaim ingredients. These include the use of high pressure water jets or compounds such as ammonia, which form fluids under pressure at elevated temperature, to remove the propellant from the motor, extraction of the ammonium perchlorate with solvents such as water or ammonia as a critical fluid, recrystalli2ation of the perchlorate and reuse in composite propellant or in slurry explosives or conversion to perchloric acid (166,167). 

Hquid—soHd preparing homogeneous slurries of light and heavy soHds such as polymers, catalyst, etc dissolving, crystallization, Hquid—soHd reactions, solvent extraction... 

In the SRC work, coal was slurried with a process-derived anthracene oil and heated to 400—455°C at 12.4—13.8 MPa (1800—2000 psi) of hydrogen for 0—1 h. A viscous Hquid was extracted. The product stream contains some hydrocarbon gases, and H2S. The residue is gasified to generate hydrogen for the process. The remaining filtrate is separated into solvent, which is recycled, and SRC, a low ash, tadike boiler fuel. 

In the liquid-hquid extraction area, in the mining industry, coming out of the leach tanks is normally a slurry, in which the desired mineral is dissolved in the liquid phase. To save the expense of separation, usually by filtration or centrifugation, attempts have been made to use a resident pump extraction system in which the organic material is contacted directly with the slurry. The main economic disadvantage to this proposed system is the fact that considerable amounts of organic liquid are entrained in the aqueous slurry system, which, after the extraction is complete, is discarded. In many systems this has caused an economic loss of solvent into this waste stream. 

Mineral Processing Slurry dilution Metal recovery by solvent extraction... 

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