英语翻译3.3.Flotation of Abu Tartour phosphate ore (sample 450)I

英语翻译
3.3.Flotation of Abu Tartour phosphate ore (sample 450)
In most of the chemical analysis of the flotation products of this
ore,loss of ignition (LOI) of thex05flotation products as well as the
concentrate weight recovery,were used as indicators for comparing
the quality of the products under various conditions.This is because
removal of carbonates was the main issue of this investigation,and
also because of the large number of flotation tests whose products had
to be chemically analyzed.
Contrary to what is expected from phosphate ores containing
carbonates,Abu Tartour phosphate ore gave acidic reactions when
soaked in water.The pH of the stirred pulp (50 g solid + 500 cc water) is
normally less than 6.0.To keep the pH of the slurry at the required pH
(5.8–6.0) in the case of Abu Tartour sample,the system pH was
artificially increased,using KOH,and then brought to the desired pH
by the addition of the phosphate depressing reagents; or the
depressing reagents (acids or acidic salts) were added first and then
the pH of the system was raised to the desired pH value by adding
KOH.This behavior of Abu Tartour sample is probably due to:a) rate of
dissolution of the carbonate minerals is very low,b) presence of pyrite
gives acidic reactions,and/or c) surface adsorption of OH−x05ions from
the system.However,this property of slow dissolution of the ore
makes the pH control of the slurry,and hence the flotation operation
quite easy.In fact,once the pH was adjusted,it remained practically
constant.
3.3.1.Effect of pH
Table 9 shows the results obtained in presence of 1.6 kg/ton KOl,
2.0 kg/ton KH2PO4at various pH values.The first test was conducted in
absence of KOH.In all other tests,KOH was added to the system in
order to increase the pH to the desired value.Fig.3 shows that the best
pH for floating carbonates from Abu Tartour phosphate sample is at
pH 5.6–5.9.Notice that selectivity of the flotation operation sharply
deteriorates over pH 6,where carbonate minerals were depressed.
Below pH 5.5,the flotation sensitivity deteriorates due to flotation