Wood preservation facilities, ammoniacal copper zinc arsenate: chapter C-2

2. Physical and Chemical Properties

Copper, zinc and arsenic are used because of their biocidal properties and their ability to be retained by wood for long-term protection. Ammonium bicarbonate facilitates the dissolution of the metals. Ammonium hydroxide is used as a solvent carrier for copper zinc arsenate; once the ammonia evaporates from the wood, the copper and zinc arsenate precipitate in the wood cells in forms that remain highly resistant to leaching. The use of ammonia also prevents copper from corroding iron components in the treating equipment.

The physical and chemical properties of ACZA and its constituents are outlined in Tables 2 and 2.1. General physical and chemical properties can be obtained from manufacturers’ material safety data sheets (MSDS) and the product labels for pesticidal products (pesticide label). Electronic copies of the pesticide label can be obtained from the Health Canada website (4).