Sulfur titanium pigment

SOLINOX SO,. Linde NO,] A process for removing both NOx and SOx from fluegases. The SOx is removed by scrubbing with tetra-ethylene glycol dimethyl ether, circulated in a packed tower (the Selexol process). The NOx is destroyed by Selective Catalytic Reduction ( SCR). The sorbent is regenerated with steam the SOx is recovered for conversion to sulfuric acid. Developed by Linde in 1985 and used in a lead smelter in Austria and several power stations in Germany. In 1990 it was announced that it would be used at the titanium pigment plant in The Netherlands operated by Sachtleben. 

Results For the St. Louis data, the target transformation analysis results for the fine fraction without July Uth and 5th are given in table 6. The presence of a motor vehicle source, a sulfur source, a soil or flyash source, a titanium source, and a zinc source are indicated. The sulfur, titanium and zinc factors were determined from the simple initial test vectors for those elements. The concentration of sulfur was not related to any other elements and represents a secondary sulfate aerosol resulting from the conversion of primary sulfur oxide emissions. Titanium was found to be associated with sulfur, calcium, iron, and barium. Rheingrover ( jt) identified the source of titanium as a paint-pigment factory located to the south of station 112. The zinc factor, associated with the elements chlorine, potassium, iron and lead, is attributed to refuse incinerator emissions. This factor could also represent particles from zinc and/or lead smelters, though a high chlorine concentration is usually associated with particles from refuse incinerators ( ). The sulfur concentration in the refined sulfate factor is consistent with that of ammonium sulfate. The calculated lead concentration in the motor vehicle factor of ten percent and a lead to bromine ratio of about 0.28 are typical of values reported in the literature (25). The concentration of lead in... 

Titanium whites resist various atmospheric contaminants such as sulfur dioxide, carbon dioxide, and hydrogen sulfide. Under normal conditions they are not readily reduced, oxidi2ed, or attacked by weak inorganic and organic acids. Titanium dioxide dissolves slightly in bases, hydrofluoric acid, and hot sulfuric acid. Owing to its chemical inertness, titanium dioxide is a nontoxic, environmentally preferred white pigment. 

Paints. Paints account for perhaps 3% of sulfur consumption (see Paint). The main sulfur use is for the production of titanium dioxide pigment by the sulfate process. Sulfuric acid reacts with ilmenite or titanium slag and the sulfur remains as a ferrous sulfate waste product. Difficulties with this process have led to the development of the chloride process (see Pigments, inorganic Titanium compounds). 

Two pigment production routes ate in commercial use. In the sulfate process, the ore is dissolved in sulfuric acid, the solution is hydrolyzed to precipitate a microcrystalline titanium dioxide, which in turn is grown by a process of calcination at temperatures of ca 900—1000°C. In the chloride process, titanium tetrachloride, formed by chlorinating the ore, is purified by distillation and is then oxidized at ca 1400—1600°C to form crystals of the required size. In both cases, the taw products are finished by coating with a layer of hydrous oxides, typically a mixture of siUca, alumina, etc. 

The analytical chemistry of titanium has been reviewed (179—181). Titanium ores can be dissolved by fusion with potassium pyrosulfate, followed by dissolution of the cooled melt in dilute sulfuric acid. For some ores, even if all of the titanium is dissolved, a small amount of residue may still remain. If a hiU analysis is required, the residue may be treated by moistening with sulfuric and hydrofluoric acids and evaporating, to remove siUca, and then fused in a sodium carbonate—borate mixture. Alternatively, fusion in sodium carbonate—borate mixture can be used for ores and a boiling mixture of concentrated sulfuric acid and ammonium sulfate for titanium dioxide pigments. For trace-element deterrninations, the preferred method is dissolution in a mixture of hydrofluoric and hydrochloric acids. 

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. 

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... 

Sulfate (1) A process for making titanium dioxide pigment from ilmenite. The ilmenite is digested with sulfuric acid, yielding a solution of litany 1 and ferrous sulfates ... 

Inorganic chemicals and fertilizers include acids (e.g., sulfuric, nitric) and alkalies (e.g., caustic soda, soda ash), chlorine, ammonia, and ammonia-derived fertilizers. They also include fluorine derivatives (e.g., hydrogen fluoride), phosphates, potash, pigments (e.g., titanium dioxide), and certain metals such as mercury. 

Another source of error in the investigation of the surface properties of titanium dioxide is its tendency to adsorb acids or ions. Phosphate ions are very strongly adsorbed (see Table XIX) as well as sulfuric acid. Commercial pigments often have considerable sulfate contents. When titania is precipitated from sulfate solution, sulfate ions are strongly adsorbed (308). They are carried through all further stages of pigment manufacture. 

Unstabilized chrome yellow pigments have poor lightfastness, and darken due to redox reactions. Recent developments have led to improvements in the fastness properties of chrome yellow pigments, especially toward sulfur dioxide and temperature. This has been achieved by coating the pigment particles with compounds of titanium, cerium, aluminum, antimony, and silicon [3.134] — [3.142]. 

Titanium whites resist various atmospheric contaminants such as sulfur dioxide, carbon dioxide, and hydrogen sulfide. Owing to its chemical inertness, titanium dioxide is a nontoxic, environmentally preferred white pigment. 

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