Sulfur ilmenite ores

Two processes are used in the manufacture of titanium dioxide pigments the sulfate process and the chloride process. The chemistry of the sulfate process, the longer established of the two methods, is illustrated schematically in Scheme 9.1. In this process, crude ilmenite ore, which contains titanium dioxide together with substantial quantities of oxides of iron, is digested with concentrated sulfuric acid, giving a solution containing the sulfates of Ti(iv), Fe(m) and Fe(n). Treatment of this... 

The other 6% of the product is made by taking ilmenite ore (45-60% Ti02) and treating it with sulfuric acid for digestion and filtration. Hydrolysis of the sulfate and final heating gives pure titanium dioxide. 

Ilmenite ore is treated with sulfuric acid the sediment of iron sulfate is filtered off. The solution is cooled to 0 °C, saturated with hydrogen chloride and mixed with solid potassium chloride. This forms a deposit of potassium chlorotitanate K2TiCU., which is not soluble in water. The salt is separated (in the filter) and sent into a rotating furnace to be heated to 300-500 °C and disintegrated. The disintegration releases vapours of titanium tetrachloride, which are sent to condense the sediment of potassium chloride is returned into the cycle. The titanium tetrachloride produced by this technique is veiy pure, since most impurities remain in the mother waters. 

Sulfate Process. In the sulfate process (Fig. 2), ilmenite ore is treated with sulfuric acid at 150—180°C ... 

Titanium dioxide is manufactured by two processes, the sulfate process and the chloride process. In the sulfate process, ilmenite ore (FeTiOg) is dissolved in concentrated sulfuric acid and insoluble impurities are removed by clarification, flocculation, sedimentation and filtration. The resulting solution is further purified by crystallization to remove ferrous sulfate from titanyl sulfate solution. The titanyl sulfate solution is then hydrolyzed to give hydrated titanium dioxide, which is calcined at about 900 to 1100 °C to give the titanium dioxide pigment. Both anatase and rutile-type titanium dioxide pigments are produced using this method. 

Becher A process for making synthetic rutile (a titanium concentrate) from ilmenite ore. The ore, typically containing 58% titanium dioxide, is first roasted with coal and 0.2%-0.5% of elemental sulfur at 1200°C in a specially designed rotary kiln. This reduces the iron in the ilmenite to the metallic state. After cooling, partially burned coal and ash are removed from the product by screening and magnetic separation. The reduced... 

Refer to Exercise 126. Iron(II) sulfate heptahydrate formed in the processing of ilmenite ore cannot be released into the environment. Its further treatment involves dehydration by heating to produce anhydrous iron(II) sulfate. Upon further heating, the iron(II) sulfate decomposes to iron(III) oxide, and sulfur dioxide and oxygen gases. The iron(III) oxide is used in the production of iron and steel. How many kilograms of iron(III) oxide are obtained for every 1.00 X 10 kg of iron(Il) sulfate heptahydrate ... 

Minerals. Iron-bearing minerals are numerous and are present in most soils and rocks. However only a few minerals are important sources of iron and thus called ores. Table 2 shows the principle iron-bearing minerals. Hematite is the most plentiful iron mineral mined, followed by magnetite, goethite, siderite, ilmenite, and pyrite. Siderite is unimportant in the United States, but is an important source of iron in Europe. Tlmenite is normally mined for titania with iron as a by-product. Pyrite is roasted to recover sulfur in the form of sulfur dioxide, leaving iron oxide as a by-product. 

Although ilmenites and leucoxenes can be used in the chloride process, ores having higher Ti02 contents, eg, mineral mtile, which is not readily attacked by sulfuric acid, are preferred in order to minimise loss of chlorine in iron chloride by-product. 

Dissolution of the ore, ilmenite, in sulfuric acid and removal of iron impurities. 

Titanium dioxide (E171, Cl white 6) is a white, opaque mineral occurring naturally in three main forms rutile, anatase, and brookite. More than 4 million tons of titanium dioxide are produced per year and it is widely used for industrial applications (paints, inks, plastics, textiles) and in small amounts as a food colorant. ° "° Production and properties — Titanium oxide is mainly produced from ilmenite, a titaniferous ore (FeTiOj). Rutile and anatase are relatively pure titanium dioxide (Ti02) forms. Titanium oxide pigment is produced via chloride or sulfate processes via the treatment of the titanium oxide ore with chlorine gas or sulfuric acid, followed by a series of purification steps. High-purity anatase is preferred for utilization in the food industry. It may be coated with small amounts of alumina or silica to improve technological properties. 

Ore deposits associated with volcanic rocks generally exhibit polymetallic (Cu, Pb, Zn, Sn, W, Au, Ag, Mo, Bi, Sb, As and In) mineralization. Sulfur isotopic values of sulfides from these deposits are close to 0%o, suggesting a deep-seated origin of the sulfide sulfur. Clay deposits (pyrophyllite, sericite and kaolinite) are associated with both felsic volcanic rocks and ilmenite-series granitic rocks of late Cretaceous age in the San-yo Belt. 

The iron sulfate crystallizes out from the titanium persulfate solution and can be recycled to make more sulfuric acid. The sulfate process uses the ore ilmenite as a raw material, while the chloride process requires rutile. Ilmenite can be converted to synthetic rutile. 

The sulfate process has traditionally used batch ore digestion, in which concentrated sulfuric acid is reacted with ilmenite. This reaction is very violent and causes the entrainment of sulfur oxides (SOA) and sulfuric acid in large amounts of water vapor. In an effort to reduce the particulate emissions, scrubbers have been installed at most plants, but these, in turn, have necessitated the treatment of large quantities of scrubbing liquid before discharge. Other waste-disposal problem products are spent sulfuric acid and copperas (FeS04-7H20). 

Suppose an ore containing 24.3% Ti by mass is digested with an 80% H2SO4 solution, supplied in 50% excess of the amount needed to convert all the ilmenite to titanyl sulfate and all the ferric oxide to ferric sulfate [Fe2(S04)3]. Further suppose that 89% of the ilmenite actually decomposes. Calculate the masses (kg) of ore and 80% sulfuric acid solution that must be fed to produce 1000 kg of pureTi02. 

There are two main processes for extracting titanium from the ores. In the first, ilmenite or titaniferous slag is attacked with sulfuric acid to form a solution of titanium. The titanium is separated as a hydrated titanium dioxide by a nucleation process which is treated to form titanium dioxide pigments. In the second process, the mineral is chlorinated in the presence of a reducing agent (usually coke) to form titanium tetrachloride. After purification by distillation, the titanium tetrachloride may be reduced with sodium or magnesium to... 

Conventional (SulfiM ) Process. Raw material is either an ilmenite (FeTiO ) concentrate from benefidation of naturally occurring ilmenite or a slag obtained from ilmenite by electrosmelting and tapping off the major part of the iron as pig iron for further use. The titaniferous material is digested with concentrated sulfuric acid, leading to a solution of sulfates of most of the metals contained in the ore, e.g. ... 

Titanium is mostly used as a pigment in Ti02- Therefore, the titanium oxide is directly produced by the following sulfuric acid process and chlorination process from titanium ores. The sulfuric acid process is the process to remove iron in the ilmenite as a solid iron sulfate with sulfuric acid. 

Examples The roasting of ores, the chemical adsorption of hydrogen sulfide by metal oxides (forming sulfides), the conversion of a metal oxide with a volatile non-metal oxide into a salt (e.g., the chemical adsorption of sulfur dioxide and oxygen by calcium oxide), the reductive chlorination of ilmenite (iron titanate) whereby iron chloride and titanium oxide are formed. In some processes a second solid reactant is present (e.g., carbon) that also reacts with the gaseous reactant, forming another gaseous reactant (e.g., carbon monoxide). 

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