Zirconic acid

Other types of refractory that find use are forsterite, zirconia, and zircon. Acid-resisting bricks consisting of a dense body like stoneware... 

Zirkonium-Btahl, m. zirconium steel. ver bindung, /, zirconium compound, Zirkon-lampe, /. zirconium lamp, -licht, n. zircon hght, -oxyd, n. zirconium oxide, prUparat, n. zirconium preparation, -saure, /. zirconic acid, stahl, m, zirconium steel. Zirkulonte,/. (Math.) circulant. 

Other types of refractory that find use are forsterite, zirconia, and zircon. Acid-resisting bricks consisting of a dense body like stoneware are used for lining tanks and conduits in the chemical industry. Carbon blocks are used as linings for the crucibles of blast furnaces, very extensively in a number of countries and to a limited extent in the United States. Fusion-cast bricks of mullite or alumina are largely used to line glass tanks. 

Colloidal Metazirconic Acid. — On boiling, the hydrosol of zirconic acid changes to metazirconic acid. For the preparation of the meta acid, metazirconium chloride may be employed. This latter substance is made by repeated evaporation of the oxychloride. By dialyzing the solution a milky liquid is obtained that closely resembles meta-stannic acid. Concentrated HCl produces a precipitate that is soluble in water. Concentrated solutions of alkali chloride behave similarly. The hydrosol is completely precipitated by sulfuric acid and the pre-... 

Flame-Retardant Treatments For Wool. Although wool is regarded as a naturally flame-resistant fiber, for certain appHcations, such as use in aircraft, it is necessary to meet more stringent requirements. The Zirpro process, developed for this purpose (122,123), is based on the exhaustion of negatively charged zirconium and titanium complexes on wool fiber under acidic conditions. Specific agents used for this purpose are potassium hexafluoro zirconate [16923-95-8] [16923-95-8] K ZrF, and potassium hexafluoro titanate [16919-27-0], K TiF. Various modifications of this process have been... 

Lead zirconate [12060-01 -4] PbZrO, mol wt 346.41, has two colorless crystal stmctures a cubic perovskite form above 230°C (Curie point) and a pseudotetragonal or orthorhombic form below 230°C. It is insoluble in water and aqueous alkaUes, but soluble in strong mineral acids. Lead zirconate is usually prepared by heating together the oxides of lead and zirconium in the proper proportion. It readily forms soHd solutions with other compounds with the ABO stmcture, such as barium zirconate or lead titanate. Mixed lead titanate-zirconates have particularly high piezoelectric properties. They are used in high power acoustic-radiating transducers, hydrophones, and specialty instmments (146). 

Two zirconium-containing minerals were discovered in North America, namely, welognite [55659-01-3] (Sr2 g Cag 2 )ZrNa2(C03 )g -3H2 0, and gittinsite [75331-27-0] Unlike zircon, the zirconium content of these minerals and eudialyte can be dissolved by strong acid. 

Oxide Chlorides. Zirconium oxide dichloride, ZrOCl2 -8H2 0 [13520-92-8] commonly called zirconium oxychloride, is really a hydroxyl chloride, [Zr4(OH)g T6H2 0]Clg T2H2O (189). Zirconium oxychloride is produced commercially by caustic fusion of zircon, followed by water washing to remove sodium siUcate and to hydrolyze the sodium zirconate the wet filter pulp is dissolved in hot hydrochloric acid, and ZrOCl2 -8H2 O is recovered from the solution by crystallization. An aqueous solution is also produced by the dissolution and hydrolysis of zirconium tetrachloride in water, or by the addition of hydrochloric acid to zirconium carbonate. 

Chemical leaching (1,12) with acids is used to extract metal contamination. High purity zirconia, Zr02, is produced by the caustic fusion of zircon [14475-73-1], ZrSiO, foUowed by the chemical removal of sUica. Chemical leaching is generaUy foUowed by washing. 

Zircon ZrOa, 67% SiOg, 33% 200 31001 Acid Excellent 25 Very low Excellent Good Very slight Very slight... 

These reactions have been studied in detail for materials such as silica, and understanding of reaction mechanisms, as well as of the role of the precursor and catalyst (acid or base), has been well documented.63,64 Similar studies have been carried out in other material systems, most notably, lead zirconate titanate [Pb(Zr,Ti)03 PZT].52,65-68 For multicomponent (mixed-metal) systems such as those noted, prehydrolysis of less reactive alkoxides is sometimes employed to improve solution compositional uniformity. Other synthetic strategies to achieve molecular level mixing of reagents have also been employed. Here, synthesis of mixed-metal alkoxides has been a focus of investigators.40-42 A key point is to restrict the amount of water and to control how it is added to form solubalizable precursor species, rather than to induce precipitation.1,52,69,70... 

HAL [Hot acid leaching] A process for purifying silica sand or zircon by leaching out surface iron compounds with hot sulfuric acid. Derived from an earlier process, invented in 1955 by British Industrial Sand, in which silica sand was treated with hot, gaseous hydrogen chloride. The process for cleaning zircon sand was developed jointly by Hepworth Minerals Chemicals, UK, and Metallurgical Services Pty, Australia, in 1991. 

Flotation of pyrochlore using sodium alkyl sulphate is dependent on flotation pH. At a pH above 5.5, no pyrochlore flotation is achieved. At this pH, microcline, limonite and aegirine were floated. It appears that the use of alkyl sulphate at slightly acidic to alkaline pH number of gangue minerals can be selectively floated from pyrochlore. At a pH between 1.5 and 3.0, alkyl sulphate floats pyrochlore and zircon, whereas floatability of limonite, microline and aegirine is greatly reduced (Figure 22.4). 

Fatty acids and their variations were examined for selective flotation of zircon from Ta/Nb. No selectivity or zirconium flotation was achieved using fatty acids. 

The acid pretreatment with HC1 was the most critical parameter. The effect of level of HC1 on zircon rejection is shown in Figure 23.8. 

Monazite is readily floatable using cationic collectors such as oleic acid and sodium oleate in the pH region of 7-11. Monazite does not float readily using, for example, laurel amine or anionic collectors. Adsorption of the sodium oleate on the monazite increases with an increase in pH, indicating that monazite does not float in acid pH, while pyrochlore is readily floatable and is depressed at a pH greater than 10. Figure 24.1 shows the effect of pH on flotation of monazite, pyrochlore and zircon. 

Limited research work has been conducted on these ores, but have indicated that REO cannot be recovered using either fatty acid or sodium oleate. It was, however, found that a mixture of sulphosuccinamate and phosphate ester modified with alkylsulphate can recover REO and zircon efficiently. Figure 24.5 shows the effect of above collector mixture (KBX3) on REO recovery from complex RE0-Zr02 ores. Oxalic acid and fatty acid (FA3) were not so effective compared to collector KBX3. 

Titanium is the most abundant metal in the earth crust, and is present in excess of 0.62%. It can be found as dioxy titanium and the salts of titanium acids. Titanium is capable of forming complex anions representing simple titanites. It can also be found in association with niobium, silicates, zircon and other minerals. A total of 70 titanium minerals are known, as mixtures with other minerals and also impurities. Only a few of these minerals are of any economic importance. 

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 ... 

Electric force microscopy, 3 332 Electric furnace acid, 11 121 Electric furnace ferromanganese production, 15 552-553 Electric furnace process, for zircon, 26 627-628... 

Rock samples collected from archived core, mine workings and outcrop were pulverized, homogenized, then analyzed using four-acid dissolution (SGS Lab, Toronto) to determine the near-total lithogeochemical composition (cassiterite, rutile, monazite, zircon, sphene, gahnite, chromite and barite are partially dissolved). Gold analyses were done by Fire Assay with Atomic Absorption finish on 30g samples and have a detection limit of 5 ppb. 

The compound is prepared by dissolving zirconium tetrachloride, ZrCh, or sodium zirconate, Na4Zr04, in hydrochloric acid solution followed by evaporation to obtain crystals of octahydrate. 

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