Mixed layer iron concentrations

Copper conversion is accomplished by a pyrometallurgical process known as smelting. During smelting the concentrates are dried and fed into one of several different types of furnaces. There the sulfide minerals are partially oxidized and melted to yield a layer of matte, a mixed copper-iron sulfide, and slag, an upper layer of waste. 

Our experimental results must be considered in the context of seasonal changes in mean irradiance and dissolved iron concentrations for ocean surface waters in our study region. Smith and van Hilst (2003) estimate mean mixed-layer irradiances of 96 58 fiE m 2 s 1 and 180 + 110 fiE m 2 s 1 in the southern Ross Sea for the periods November... 

The results of our two experiments are consistent with these seasonal changes in the availability of light and iron, given the interrelated influences of irradiance and iron availability on phytoplankton growth rate. The data from our laboratory dose-response iron-addition experiment indicate a relatively high iron requirement for colonial Phaeocystis at an irradiance of 20 fiE m 2 s-1, a value that is representative of the mean irradiance in the mixed layer of the southern Ross Sea during early spring (Smith et al. 2000 Smith and van Hilst 2003 Hiscock 2004). At that time, dissolved Fe concentrations are likely to exceed our estimated half-saturation... 

Although the number of samples analyzed is limited, the inescapable conclusion to be drawn from our data is that some of the Nile silt formations can be differentiated on the basis of trace element contents and REE distribution patterns. In addition, we conclude that the Early Predynastic (Amratian) pottery was made from clays found in the immediate vicinity of the kiln. Older shales that are found layered with the much earlier sandstone deposits that were cut by the Great Wadi were also analyzed. The REE patterns as well as the scandium, chromium, and iron concentrations are different enough to suggest that these materials were not used to produce pottery (21), In a previous paper, we discussed the possibility that some of this shale, or the white salt found associated with it (anhydrite-CaSOj, was mixed with the local clay to produce the finer, harder plum red ware (21). This addition could account for the slight difference in the average composition of the sherds from localities 11, 39, and 59 and the Masmas silt. 

The first two unenclosed iron-enrichment studies were carried out in 1993 and 1995 in the Equatorial Pacific. In both, nanomolar concentrations of iron were induced in the surface layer by release of iron sulfate, the patches being labeled by SFg addition. The SEg(initial addition of iron, the tracer component was then used as a guide to keep track of the affected patch of ocean. Sampling could be reliably categorized as in or out the patch, even after all the measurable iron had disappeared from solution. In the second study, the main experiment included reseeding the patch with iron, but not tracer, twice after the initial release. Important secondary aims of the tracer component of the experiments have been the study of mixing rates both horizontally in the mixed layer, and vertically across the thermocline. 

Mix 0.25M substituted benzaldehyde, 0.3M nitroethane, 50 ml dry toluene and 5 ml n-butylamine (or other amine), and reflux 3 hours with a Dean-Stark trap (or prepare the nitro-propene as described elsewhere here). Add 50 g iron powder and 1 g FeCl3 optional) and reflux while adding 90 ml concentrated HCI over 3 hours. Reflux 1 hour more, add 2 liters of water and extract 3 times with ether, then dry and evaporate in vacuum (or steam distill until about 3.5 liters of distillate is obtained extract the distillate 3 times with toluene wash the toluene layers with 7 g NaHS03 in 225 ml of water, then 3 times with water and dry, evaporate in vacuum) to get the ketone. Mix 0.13M ketone, 28 g formamide (or dimethyl-formamide if the N.N-dimethylamine is desired) and 3 ml formic acid and heat at 160°. Add 3 more ml formic acid and heat 16 hours at 170-180° adding formic acid from time to time to keep the pH acid. Distill off the water formed (about 16 ml), cool and extract with 3X70 ml benzene. Distill off the benzene and reflux the residue 7 hours with 30 ml concentrated HCI. Chill, basify with 10% NaOH and extract with 3X70 ml ether. Dry and evaporate the ether in... 

The lower reddish oily layer is separated, mixed with an equal volume of 10 per cent sodium hydroxide solution and steam distilled from a 2-1. flask until no more oil passes over. Towards the end of the distillation a yellow solid begins to collect in the receiver this consists of nitro compounds, which are removed by vigorously stirring the oil for about three hours with 20 cc. of concentrated hydrochloric acid, 300 cc. of water and 200 g. of iron filings in a 2-1. flask connected with a reflux condenser. 

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