Gold Processing – pH

Telfer, Western Australia, 2005.

Due to the highly complex gold and copper ore mixing process, the presence of sulfides and fluorides produce dissolved gasses that wreaked havoc on sensors, rendering most pH sensors unusable. Utilising our sensors with a unique triple junction design, coupled with our acid/fluoride resistant glass, and sulfide resistant junction, we drastically reduced the dissolved gas attack, increased the resistance to high cyanidation and sulfides, while the overall tough construction of the sensor was able to withstand the fluctuating solids content at high velocity. For more than 10 years now our Turtle Tough sensors have been experiencing more than 8-10 times the life span of the previous sensor.

Nickel Processing – pH

Ravensthorpe, Western Australia, 2011.

Due to the intense pressure associated with the pressure acid leach process, the previous sensors were only lasting a couple of days. The Turtle Tough sensor is now providing pH measurements that are accurate and reliable, and the sensors require very little maintenance compared to the previous sensors. They are lasting upwards of 5-10 times as long with far fewer maintenance requirements. This has not only reduced the cost of ownership, but more importantly provided confidence in measurement and improved process control.

 

Titanium Dioxide

Kwinana, Western Australia, 2000.

Dissolved chlorine gases were deteriorating sensors so fast that calibrations were attempted twice a day, with a new sensors being used every 1-2 days. A special glass formulation was required for this application to provide chlorine and dissolved gas resistance. The Turtle Tough sensor provided much greater accuracy and was able to survive for months at a time, providing as much as a 12 times gain in life expectancy.

 

Zinc Processing

Lawn Hill, Queensland, 2005.

A major zinc producer’s pH sensors were unable to cope with the solids content and composition in their process, causing the reference junction to persistently clog and foul. Additionally, poisoning of the glass by high concentrations of zinc was reducing response and shortening the sensor’s life even further. Utilising our zinc resistant glass we provided a replacement sensor with our slurry/viscous design which is able to withstand high velocity and high solid content environments. Sensor life expectancy was increased 6-8 times, and hands-on maintenance time was significantly reduced.

Waste Water – Poultry Farm

Girraweene, New South Wales, 2010.

A large chicken farm ‘s pH sensors were only lasting 1-2 weeks in the wastewater treatment and water discharge monitoring locations. The wastewater treatment required the pH to be lowered from pH 10 to pH 4 to precipitate the solids out. The pH then needs to be raised to between 7 and 10 at discharge to satisfy local environmental regulations.

By utilising a Turtle Tough sensor with Acid/ Fluoride and Sulphide resistance we were able to increase sensor life by up to 6 months which is at least 12 times the life on the sensors being used previously.

Gold Processing – pH

Westonia , Western Australia, 2013.

A gold mining company contacted us with issues of erratic readings and general unreliability with their existing measurement system. As is common with many smaller processing facilities, electrical components and equipment being installed in close proximity to one another can generate a lot of electrical noise interefering with measurement systems.

Our Turtle Tough pH sensor with integrated premaplifiers and anti-noise coaxial cable solved the problem, allowing for noise free signal transmission. Despite being a relatively easy application; a gold carbon-in-leach (CIL) process, our industrial sensor configuration still outlasted the previous sensor by 3-4 times.

Nickel Processing – pH and ORP

Leonora, Western Australia, 2000.

The high pressure acid-leach process at this nickel cobalt plant was destroying pH sensors. The initial problems were so severe that it made it near impossible to control the process. At many critical measurment points sensors were being destroyed within days, sometimes hours.

Several unique Turtle Tough sensor designs have been used throughout the plant to acheive the desired lifetime and performance. We are using some of our most extreme reference junction configurations, with triple junction, acid/fluoride resistance, sulfide resistance and teflon silicon sealing. The most extreme sensors requiring preamplification are typically mated to our TT-3TX and existing Rosemount analysers, while less demanding applications are utilising existing Yokogawa analysers.

Sugar Refining – pH

Queensland, 2005.

A large sugar refiner wanted to reduce the cleaning and calibration frequency of the pH control system in their evaporation and boiling sugar refining process. High temperaturecalcium deposits andviscous sugar syrup required aggressive cleaning and time consuming calibration. They were also experiencing frequent sensor failure and the replacement time was slowing production.

We designed a Turtle Tough sensor with a thick wall, crack resistant pH glass sensing element, combined with a specially engineered ultra-high temperature resistant non-porous conductive polymer reference system. By closely matching the expansion coefficients of all the components we were able to reduce sensor failure from the severe temperature cycling. A temperature sensor was embedded in a sealed design to avoid failure, which is common failure mode of many sensors. The resulting sensor greatly lowered maintenance frequency and sensor failure providing a greater product yield and reduced operating costs.

Gold Mining – Cyanide

Masbate, Philippines, 2013.

A large gold mine situated in the Philippines needed to monitor cyanide levels at below 0.2ppm. They were using an expensive automated WAD analyser that was incapable of reliably measuring below 3ppm. The target rate for discharge was less than 0.1ppm with the upper end limit being set at 0.2ppm as the maximum environmental allowance.

A Turtle Tough Cyanide Analyser was installed in the mine sites water treatment plant detoxification area.

The mine site had extremely high flow rates, so a 30mm off-take line was utilised with a flow rate slowed to approximately 2L/m. This provided optimal conditions for stable measurement at such low cyanide levels. The optimum pH range for such a low level detection is between pH 9.5 and 10.0. The raw water feed on-site had an ideal pH of 9.8, so no dosing was required.

Utilising the standard 4-20ma analogue output into their SCADA system the mine site are able to continuously monitor their discharge water. Due to the critical nature of this environmental monitoring the site chose to install a second system for double redundancy. Site personnel are extremely happy with the simplicity and performance of the system. Results are stable and coincide with all lab results. The cost of this monitoring solution was less than a third of competitive systems.