Vanadium powder

Vanadium powder can be prepared by substituting V2O2 for the V20 as the vanadium source. The heat generated during the reduction of the trioxide is considerably less than for the pentoxide, so that only soHd products are obtained. The powder is recovered from the product by leaching the slag with dilute acid. 

Vanadium powder, dust, and most of its oxide compounds are explosive when exposed to heat and air. They are also toxic when inhaled. Vanadium chloride compounds are strong irritants to the skin and poisonous when ingested. 

The authors would like to acknowledge Drs S. Hantzer, S. Soled and M.S. Touvelle for helpful discussions. We also thank Mr S. Miseo for the X-ray diffraction characterization of vanadium and vanadium powder materials. We would also like to acknowledge Drs R. Kapoor and S.T. Oyama of Virginia Tech, for providing the vanadium carbide powder sample used in Figure 24.4. 

Vanadium, powder by reduction of oxide with calcium, 6 50 Vanadium(II) chloride, 4 126 Vanadium (III) chloride, 4 128 6-hydrate, 4 130... 

Ignition or explosive reaction with metals (e.g., aluminum, antimony powder, bismuth powder, brass, calcium powder, copper, germanium, iron, manganese, potassium, tin, vanadium powder). Reaction with some metals requires moist CI2 or heat. Ignites with diethyl zinc (on contact), polyisobutylene (at 130°), metal acetylides, metal carbides, metal hydrides (e.g., potassium hydride, sodium hydride, copper hydride), metal phosphides (e.g., copper(II) phosphide), methane + oxygen, hydrazine, hydroxylamine, calcium nitride, nonmetals (e.g., boron, active carbon, silicon, phosphoms), nonmetal hydrides (e.g., arsine, phosphine, silane), steel (above 200° or as low as 50° when impurities are present), sulfides (e.g., arsenic disulfide, boron trisulfide, mercuric sulfide), trialkyl boranes. 

Figure 6.1 Recorded combustion images of vanadium powder compacts preheated at 200°C in nitrogen of 1.14MPa (a) without VN dilution and (b) with 30-wt% VN dilution.

To 325-mesh vanadium powder (3.87 g, 76.0 mmol) in a 250-mL round-bottomed flask equipped with a reflux condenser is added p-toluenesulfonic acid monohydrate (43.3 g, 228 mmol) and water (20 mL). The mixture is heated to reflux for 16 h. A deep purple solution is obtained, and some metal powder is still present. The mixture is filtered while hot through Celite and the purple filtrate concentrated to 10 ml. by vacuum distillation. The solution is cooled to room temperature, and large pale purple needles are deposited. The crystals are collected by filtration and dried overnight under vacuum at room temperature. Additional crops can be obtained from the filtrate by concentrating it to 5 mL by vacuum distillation, and then cooling the resulting solution to room temperature. Yield 23.0 g (45.1%). 

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