Barite Processing Plant

Barite flotation line

The flowsheet of the processing plant is shown in Figure. It consists of a multi-stage crushing section, the gravity separation plant and a flotation line.

The Barite ore is drawn from the stocpiles by means of a wheel loader and fed via apron feeder to the primary jaw crueher where it is reduced to below about 200 mm; the oversize of the 70 mm screening is then further ground in the secondary jaw crusher. Where necessary the ore is passed through a logwasher for desCiros; otherwise it is, sent direct to a third Hydrocone crusher in closed circuit with a 20 mm screen, where final size reduction takes place.

The granulated product is stored in a bin of 1,200 tonnes capacity heading the gravity section.

The upgrading process consists of two jigging stages in series. In the first stage, the entire feed range (—20 mm) is treated in two parallel oscillating frame jigs, each having a throughput capacity of 45 t/h.

Coarse waste is screened for recovering classified aggregates for civil engineering applications (road construction or concrete bricks); the finest (—3 mm) class may still contain residual barite values worth recovering by flotation, according to market price.

PreconcentrUte, dewatered in a screw classifier, is completely ground to below 8 mm with a short-head simons cone in closed circuit with a 8 mm vibrating screen; dewatenng fines are thickened and sent to flotation.

The final cleaning stage is carried out in four fixed frame jigs, each having a capacity of 7-8 t/h, both final concentrate and middlings are dewatered in separate screw classifiers, overflowing fines still contain a considerable proportion of bante and are thus amenable to flotation after settling in a Dorr thickener Coarse middlings are treated in the same way as coarse preconcentration waste

Prom the above it emerges that notation feed consists of the thickened pulp from the Dorr settling vessel with a possible addition of the C—3 mm) class of coarse waste screening. The feed material is ground to minus 40.4 mm in a ball mill controlled by rake classifier; the resulting pulp, after conditioning with about 1 kg/t of Na-silicate at a pH around 10, is subjected to rounghing with the addition of slightly more than I kg/t of N’a-cethylsulphate; froths are recleaned twice to obtain a filter cake assaying about 95 % BaSCX

Ore Characteristics and Technical Result

All the ores mined from the various orebodies are beneficiated following the flowsheet outlined above. However the ensuing technical and economic results are quite different depending on the origin, i. e. the BaSOi grade of the ore and. above all, the intergrowth characteristics. For this purpose, the run-of-mine can be classified into two main classes:

A — Crude ores whose components can be liberated at a relatively coarse size (8-10 mm), and are thus easily washable with gravity methods;

B — Crude ores characterized by a relatively fine dissemination of silica, barely separable at the granulation size; its gravity be-neficiation poses some problems due to the poor concentrate quality as well as the considerable losses in the waste.

On the other hand flotation yields similar results for both ores, barite being sufficiently liberated at the grinding size (—0.4 mm). The only difference is a higher Sl02 content of concentrate from ore B but this does not represent a drawback since concentrates are blended before delivery to the same customer.

High quality (up to 95-96 % BaSOJ concentrates can be obtained from ore A, whereas those obtainable from ore B are considerably poorer and fall short of drilling mud specifications (4.20 specific gravity, corresponding to 89-90 % BaSCW. For this latter ore barite recovery rapidly deteriorates when concentrate grade is to be forced beyond 86 %. Moreover it should be underlined that, although the barite values lost in the jigging phase are partially recovered by subsequent fiotation. overall benef.iciation economics is worse than for ore A, since flotation is considerably more expensive.

In brief, ore availability and process flowsheet enable the following products to be obtained:

  • granular high grade barytes assaying up to 94-96 % BaSO. with low silica content;
  • granular barytes of poorer quality (less than 87-89 % BaSCu), contaminated with a relatively high proportion of silica (exceeding 5 %)\high grade notation concentrate (above 95 % BaSCu);
  • classified aggregates for civil engineering applications.

Flowsheet Optimization

The major commercial outlets for concentrated barytes are the chemical industry for barium salts manufacturing and the deep well oil exploration activity as weighing agent of drilling muds.

In the latter case granular barytes are preferable due to easier grinding and size control; the presence of small proportions (up to 25 % by weight) of flotation concentrates may be tolerated provided reagent drawbacks are minimized; specific gravity must be at least 4.20 kg/dm’. The chemical industry accepts either granular or filter cake barytes and sometimes even blends thereof provided that Sl02 content does not exceed 1.5 %.

In view of the above market restrictions as well as the technical processing results for each kind of ore, blending of the various concentrates can be economically beneficial. Different schemes may be devised such as, for instance, blends of all the available products for supplying either the chemical or the oil industry or both, or blends for the oil industry involving jig concentrates only, while the whole fiotation concentrate together with part of richer jig concentrate from ore A could be destined to the checimal industry, and so on.

Of course, the most advantageous of the available options will be dictated by the respective proportion of each kind of ore and. above all by the actual market situation (demand and prices).

Currently, owing lo the recent fall in oil prices, the demand for drilling muds application, by far the largest for barite concentrates, has suddenly dropped. Consequently, the market structure has undergone a major change compared to the previous period: chiefly to do with the more stringent quality requirements for the different utilizations: oil service companies tend now to refuse blends with products containing notation reagents, whereas manufacturers of barium salts accept only high grade concentrates with very low pollutants. Moreover, over the last few years market prices have fallen considerably in real terms.

Under these circumstances, the production schedule has had to be adjusted the new problem being that of optimizing production schedule in order to maximize profit while satisfying market demand.

Under the restriction that flotation concentrates are in any case to be destined to the chemical industry alone, the available alternative options consist of either:

  • a blend involving the whole jig concentrates production:
  • a blend for the oil industry consisting of the entire concentrate from ore B and that part of the concentrate from ore A exceeding the demand of the chemical industry, which presently pays higher prices.

Computer simulation results while confirming that the resort to blending is always profitable, reveal that the first option is better as long as the availability of ore B is greater, otherwise the choice is indifferent. Optimum gravity concentrate grade for each kind of ore separately processed depends of course on the respective proportion of each ore fed to the plant, which in turn is influenced by the available reserves as well as by the mining restrictions.

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One Response to “ Barite flotation line ”

  1. Demand:Mobile Screen Classifier | Materials: Gold ore | Customer from Philippines Says:

    Price of Screen Classifier with rated capacity of 15 to 20tph

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