Bulk flotation

Comparison of metallurgical results using conventional and bulk flotation flowsheets on ore... 

Bulk flotation followed by sequential flotation of gold-bearing sulphides, and depression of stibnite. This method was practiced at the Bradly concentrator (USA)... 

Table 17.8 Plant metallurgical results obtained using a bulk flotation method ...

Arsenical gold ores that do not contain significant base metals are treated using a bulk flotation method, where all the sulphides are first recovered into a bulk concentrate. In case the gold is contained either in pyrite or arsenopyrite, separation of pyrite and arsenopyrite is practiced. There are two commercial methods available. The first method utilizes arsenopyrite depression and pyrite flotation, and consists of the following steps ... 

The apatite barite bulk flotation was accomplished with a mixture of tall oil fatty acid and sulphonate (Aero 827) at an alkaline pH. Sodium silicate and caustic tapioca starch were used for pyrochlore depression during the bulk apatite barite flotation stage. 

The cationic flotation of Ta/Nb was not effective, as they tend to float feldspar-bearing minerals. The effect of some amines on Ta/Nb-Zr bulk flotation is illustrated in Table 23.6. 

Rutile/ilmenite-zircon bulk flotation and separation... 

Several large deposits of fine mineral sands containing mtile, ilmenite and zircon exist in Australia (Wimmera mine) and in the Soviet Union. The mtile, ilmenite and zircon cannot be preconcentrated. In most cases, flotation was used which involved bulk flotation followed by titanium-zircon separation. Over the years, several effective processes have been developed for bulk flotation followed by titanium-zirconium separation. The type of... 

The bulk flotation can be accomplished with the addition of small doses of oleic acid plus oxidized emulsion of fuel oil. The fuel oil is treated with 10% solution of NaOH at a temperature of 60-80°C for 1 h. The following method was used for rutile-zircon separation the concentrate was thickened, followed by heat conditioning to 60°C. After the heat treatment, the zircon was floated without the addition of collector. The zirconium tailing is the rutile concentrate. The zircon concentrate was thickened, followed by gravity cleaning. In some cases, the heat-treated pulp is washed before zircon flotation. The following metallurgical results were obtained ... 

Method 2- It involves bulk flotation of rutile, ilmenite and zircon followed by selective flotation of mtile and ilmenite and depression of zircon. Figure 25.16 shows the flowsheet with type of reagent additions used in selective flotation of titanium from zircon. 

Effect of level of silicate tall oil mixture and conditioning time on bulk Ti/Zr bulk flotation... 

Dreisinger, D.B., Molnar, R., Mezei, A., Baxter, K. and Wardell-Johnson, M., The Recovery of Nickel and Cobalt fi om the NorthMet Deposit Using Bulk Flotation and Chloride Assisted Pressure Leaching , Proceedings of ALTA 2010 Ni-Co-Cu Forum, Perth, May, 2010. 

The carbon black (soot) produced in the partial combustion and electrical discharge processes is of rather small particle si2e and contains substantial amounts of higher (mostly aromatic) hydrocarbons which may render it hydrophobic, sticky, and difficult to remove by filtration. Electrostatic units, combined with water scmbbers, moving coke beds, and bag filters, are used for the removal of soot. The recovery is illustrated by the BASF separation and purification system (23). The bulk of the carbon in the reactor effluent is removed by a water scmbber (quencher). Residual carbon clean-up is by electrostatic filtering in the case of methane feedstock, and by coke particles if the feed is naphtha. Carbon in the quench water is concentrated by flotation, then burned. 

Generally, Httle is known in advance concerning the degree of homogeneity of most sampled systems. Uniformity, rarely constant throughout bulk systems, is often nonrandom. During the production of thousands of tons of material, size and shape distribution, surface and bulk composition, density, moisture, etc, can vary. Thus, in any bulk container, the product may be stratified into zones of variable properties. In gas and Hquid systems, particulates segregate and concentrate in specific locations in the container as the result of sedimentation (qv) or flotation (qv) processes. 

On the basis of the function it performs, the flotation process can be divided into two categories (i) bulk and (ii) selective. The process is called bulk or collective flotation when it accomplishes the separation of several valuable components from the gangue minerals. In selective flotation, one valuable component is separated from several others. This selectivity could be accomplished by either using collectors selective with respect to a particular mineral or by differential flotation wherein two or more mineral concentrates are recovered consecutively from the same feed by using modifiers. 

Krofta, M. and Wang, L.K., Pollution Abatement Using Advanced flotation Technology in the Paper and Pulp Industry, Powder and Bulk Solids Conference, Rosemont, Chicago, IL, May 1985. 

Flotation feed ------ Bulk rougher -------->- Bulk scavenger... 

The second method involves depression of pyrite and flotation of arsenopyrite. In this method, the bulk concentrate is treated with high dosages of lime (i.e. pH> 12), followed... 

The type of collector and flowsheet configuration play an important role in gold recovery from these ores. With a flowsheet that uses bulk Cu-Pb flotation followed by Cu-Pb separation, the gold recovery is higher than that achieved with a sequential Cu-Pb flotation flowsheet. In laboratory tests, and Aerophine collector type, in combination with xanthate, had a positive effect on gold recovery as compared to either dithiophosphate or thionocarbamate collectors. Table 17.10 compares the metallurgical results obtained with an Aerophine collector to those obtained with a dithiophosphate collector. 

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