PAX Mixer shipped to Vale Thompson
Zeroday shipped a 2600-gallon PAX (potassium amyl xanthate) mixer to the Vale mill in Thompson, ON Canada on June 5, 2015. Vale has been receiving deliveries of liquid xanthate and for cost savings purposes decided to mix their own xanthate solutions from dry pellets. A new xanthate mixer was required which will be incorporated with their existing day tank-feeding system. In close collaboration with Vale engineering department, Zeroday designed, engineered, fabricated and assembled the custom system that was to fit through existing mill doors and utilizes an existing overhead crane for bulk bag unloading.
Key mixing tank system elements included:
- System included mixing tank designed to strict code requirements for mixing xanthate solutions with stairs and platform access.
- Hopper designed to break 950 kg bulk bags with hopper spike with offset chute to 9.8 m3 (2600 gallon) mix tank. Side dust vents on hopper connected to ventilation system that was integrated into system for capturing fugitive xanthate dust. Hopper lids to isolate close hopper for ventilation purposes.
- Round closed tank with conical bottom to eliminate sludge build up inside tank. The design incorporated a 3 way valve for recirculating solutions from bottom to top of tank during mixing and then for transfer to day tank.
- Mixer system and supporting stairway structure required PE stamped drawings before fabrication. UL testing and certification was obtained on completed tank.
- Xanthates solutions degrade generating explosive CS2 gas (at high enough air concentration). The system met rigorous anti-spark, explosion proof requirements, and dust and gas ventilation controls.
- Mixer motor, 1.5 hp custom ventilation fan unit, and level monitoring ultrasonic all NEMA 4x and explosion proof rated. Gases ‘scrubbed’ with carbon for enhanced control of generated organic and CS2 gas concentrations.
- Properly sized AFX Mixing Technologies mixer including stainless steel shaft and prop sized for suspending xanthate pellets during mixing until dissolved.
Zeroday has basic mixing and feeding system designs for explosive gas generating chemicals including xanthates, sodium sulfide (Na2S) and sodium metabisulfite (MBS – Na2S2O5) that fully meet strict code requirements.
