Mercury vapor discharge lamp containing means for reducing leachable mercury

Abstract

An improvement in a mercury vapor discharge lamp having an envelope of light-transmitting vitreous material containing an inert starting gas and a quantity of elemental mercury at least in part convertible to soluble mercury, and first and second electrodes located within the envelope for an arc discharge therebetween. The improvement comprises an effective amount of a soluble copper-containing compound in combination with an effective amount of a selected one of a group of materials consisting of a soluble chloride, a soluble bromide, a soluble nonmetallic iron-containing compound, and a soluble nonmetallic manganese-containing compound. The copper-containing compound and the material in combination, when the lamp is pulverized into granules and subjected to a suitable aqueous acid solution, produce a concentration of extracted mercury of less than 0.2 mg/l of the aqueous solution. The effective amount of the copper-containing compound is substantially smaller than is required to produce the concentration of extracted mercury without the materials present, and the effective amount of the selected material is smaller than is required to produce the concentration of extracted mercury without the copper-containing compound present.