ISO 4285:1977

Overview

ISO 4285:1977 - "Phosphoric acid for industrial use - Guide to sampling techniques" provides practical guidance for taking, preparing and storing representative samples of industrial phosphoric acid. Approved by IUPAC and developed by ISO/TC 47 (Chemistry), the standard covers sampling from large containers and mobile tanks, handling thermal-process and wet-process acids, equipment selection, mixing and heating methods, and essential safety precautions for quality assessment.

Key topics and requirements

• Scope and field of application
  • Applies to ortho‑ and polyphosphoric acids from thermal and wet processes, and to crystallized phosphoric acids.
• Sampling plan and procedures
  • Emphasizes taking representative samples (often three primary samples at bottom, mid‑height and surface) and sampling during filling/emptying when possible.
  • For transfers, recommends three samples at start, mid‑point and end of transfer.
  • For small containers (e.g.,