Pyrite cinders

Because calcium oxide comprises about 65% of Pordand cement, these plants are frequendy situated near the source of their calcareous material. The requisite silica and alumina may be derived from a clay, shale, or overburden from a limestone quarry. Such materials usually contain some of the required iron oxide, but many plants need to supplement the iron with mill scale, pyrite cinders, or iron ore. Silica may be supplemented by adding sand to the raw mix, whereas alumina can be furnished by bauxites and Al202-rich flint clays. 

Chlorides and sulfates Pyrite cinder from chloride and sulfate processes... 

The curves in Fig. 22 were calculated by means of the above equation, the points being experimental values. Figure 24 (Kwauk, Wang, Li, Chen and Shen, 1985) shows empirical correlations for the constants e and ea for FCC catalyst, fine and coarse alumina, pyrite cinder and iron ore concentrate. 

Zincex [Zinc extraction] A process for extracting zinc from pyrite cinder leachate, using organic solvents. The chloride leachate is first extracted with a secondary amine, and then with di(2-ethylhexyl)phosphoric acid to remove iron Developed by Tecnicas Reunidas, first commercialized in 1976, and now used in Spain and Portugal. 

Secondary amine extractants are used for the recovery of zinc from liquors obtained by the leaching of pyrite cinders at the Metalquimica del Nervion plant in Bilbao, Spain,69 and at the Quimigal plant near Lisbon, Portugal.91 Traces of other metals that also form chloro anions, such as copper, cadmium and iron(III), are also extracted, and both plants use a second extraction cycle with D2EHPA to further purify the zinc solution prior to electrowinning. 

Experimental values for e and ea for five kinds of solid materials— FCC catalyst, fine alumina, coarse alumina, pyrite cinder, and iron ore concentrate—ranging in character from Geldart s Group A to weakly Group B, are shown in Fig. 58 (Li et al., 1982, 1981). The correlation could be fitted with the following empirical equations (Kwauk et al., 1985) ... 

Institute of Chemical Metallurgy, Division III, Staged Fluidized Leaching of Products of Chioridizing Roasting of Pyrites Cinder—Preliminary Process Design (in Chinese, unpublished), 1965-7-31 (1965). 

In commercial practice, the ferric oxide is obtained from pyrites cinder, and experience shows that its catalytic activity is greatest if the ferric oxide is used fresh and not first allowed to get cold.6 It appears that if the air required for oxidation of the pyrites is dried previous to admission to the burners, the resulting mixture of sulphur dioxide and air is more sensitive to the action of the catalyst than is otherwise the case. Under highly favourable conditions 90 per cent, of the sulphur dioxide is converted into sulphur trioxide, and a conversion of 60 per cent, is quite readily obtained. 

We believe the discrepancy is due to the following points which are not taken into account in these various formulas. First, if we assume we have a continuous agitation system made up of four agitators, in which we are leaching pyrites cinders with 10 per cent sulphuric acid the system will become balanced and the strength of the sulphuric acid in the four tanks will become constant. For purposes of comparison, we will assume this to be ... 

Among the largest users of agglomeration technologies are iron and steel mills and their raw material suppliers, the cement industry and fertilizer producers. In the first area flotation concentrates and ores that were upgraded by other methods, fine or dusty pyrite cinders, red mud from bauxite processing, filter... 

Metallic iron Residual from pyrite cinder (Brown, 1948)... 

Alp, I., Deveci, H., Yazici, E. Y., Ttirk, T. Sungun, Y. H. (2009). Potential use of pyrite cinders as raw material in cement production Results of industiial scale trial opQYaiions. Journal of Hazardous Material, 166, 144—149... 

Key words Pyrite cinder. Roasting, Magnetic separation. Desulfurization... 

Pyrite cinder is produced as a by-produet of sulfurie acid industry Domestic production is more than 12 million tons every year and occupied area is over 10 million square meters The pyrite cinder outdoor not only pollutes air but also damages surrounding surface It after treatment used for iron-making is an ideal reclamation approach for its rich iron which is commonly 40-60% But pyrite cinder gets low utilization for its low iron grade and high sulfur content in China Therefore, comprehensive utilization of pyrite cinder has profound significance to environmental protection and the development of domestic iron and steel industry. 

Chemical composition of pyrite cinder is shown in Table I. Iron grade of this ted cinder is 53.51% which is moderate and FeO content is 2.68%. TFe / FeO of this red cinder is 19.97.It belongs to oxidation cinder. Content of gangue such as Si02, CaO is relatively high. Thus, the removal of gangue is necessary to improve iron grade of pyrite cinder. 

Phase composition of Ferrum, Silicon and Sulfur of pyrite cinder are shown in Table II IV. The main iron material is hematite, and the content of iron sulfide, ferric sulfate and iron silicate is low. Si02 accounting for more than 60% mainly exists in the form of free Si02. Sulfur content is high and it mainly exists in the form of sulfate. 

Table . Phase Composition of Ferrum in Pyrite Cinder /%...

Iron behavior of pyrite cinder in roasting process at 600 was studied, which can be seen in Table VI. It showed that the iron grade of roasted cinder increased for decomposition and volatilization of part of sulfate and crystal water. A large number of hematite was reduced to magnetite which led to susceptibility dropping considerably, and made roasted cinder easy to be separated. 

Table . Iron Behavior of Pyrite Cinder in Roasting Process /%...

Figure 5. Reasonable flow chart of processing pyrite cinder Conclusions...

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