pH Sensor for Nickel

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SKU: TT-Ni-pH-2103.

pH Sensor for Nickel

  • Designed Specifically for HPAL
  • 6m cable
  • RADEL with ¾” Front End – 1” Back End MNPT
  • -5°C to 135°C
  • Fast Response TC for calibration accuracy
  • Triple Junction
  • Solvent Resistant
  • Acid/Fluoride Resistant
  • Ammonia, Chlorine and Sulphide Gas Resistant
  • High Capacity KYNAR Reference
  • Proprietary toughened glass
  • Digital smart sensor technology (optional)
    • No hard wiring – plug-n-play connectivity
    • Sensor stores calibration data, analyser configuration and sensor history
    • Hot-swap for quick sensor change-out
    • No interaction with analyser – sensor data auto uploads
  • Description
  • Downloads
  • Application & Use
  • Case Studies

TT-Ni-pH Nickel pH Sensor

There is perhaps no other sensor that we are more famous for than our TT-Ni-pH Nickel pH Sensor which has been used in Nickel extraction and refining process (HPALfor more than 20 years.

Ammonia injection and solvent extraction are two critical components of nickel extraction in process environments. Dissolved gas ingress into the sensing elements of pH sensors is a common cause of premature sensor failure.  Solvent extraction also presents some unique challenges to pH measurement, as the presence of organic solvents will dissolve many common materials of construction while the small water volumes in the extraction process frequently present very extreme pH measurements.

The TT-Ni-pH Nickel pH Sensor utilises special body plastics and sealants to resist solvent attack and our sensing elements are protected from dissolved ammonia gas ingress through a triple junction references and high impedance glass electrodes. Optionally, additional cable isolation can be added to provide more resistance to the electrical components of the sensors.  The sensor is rated to above 150psi allowing the sensor to perform its task in high pressure acid leach and solvent extraction environments.  Turtle Tough have developed a range of mating interfaces, including immersion, submersion and hot-tap assemblies to ensure you can obtain your process measurement right where it is needed, rather than just settling on an easy access point.

Digital Smart Sensor Technology (DSST)

This sensor is available with our digital smart sensor technology. This plug and play sensor has a quick connect fitting, eliminating the need for hard wiring to the analyser. On-board sensor memory allows the storage of calibration data, analyser configurations and sensor service history. This allows the sensor to be conveniently maintained and calibrated off-site or in the laboratory and pre-programmed with calibration data and analyser configurations.  This stored information automatically uploads to the analyser upon connection and eliminates the need for any interaction with the analyser, greatly simplifying the change-out of sensors. A service log stored on the sensors is ideal for maintenance and quality assurance records.


Specifically designed for the Nickel industry.  Any process media containing free sulfide species such as hydrogen sulfide gas (H2S), hydrogen sulfide (HS-) or sulfide ions (S2-). Any measurement where aggressive chemical cleaning is needed to remove fouling or low-maintenance operation is required with minimal cleaning and re-calibration.

Application Difficulty Index: 9/10

This sensor is design for difficult applications with a difficulty index up to 9/10

Maintenance FREE

Turtle Tough pH and ORP sensors are a completely sealed assembly and are sealed for life.  This provides extreme process resistance as well as a totally maintenance free sensor which greatly increases sensor life and reduces labour costs.  A Turtle Tough sensor does not contain any O-rings, washers, gaskets, or serviceable components/assemblies. It does not require refreshing or refilling of electrolyte. The only requirement is regular cleaning in accordance with our recommended cleaning schedule for your application. Regular cleaning will prolong the life of your sensor and ensure hassle free operation.

Recommended Cleaning Schedule

The recommended cleaning interval is based upon the difficulty index for your application.

Recommended Cleaning Schedule

Application Difficulty Rating

Cleaning Schedule








Twice (2x) per week



If a Turtle Tough pH/ORP sensor response slows down, it is most likely the result of a fouled reference or dirty coated glass.  Cleaning should be performed as required and will vary across applications.  See cleaning instructions.


The standard shelf life for all Turtle Tough pH and ORP sensors is one year from the date of shipment. Sensors stored longer than this period may still be functional but are no longer under warranty. Sensors should be stored in a cool, dry location with the sensor tip (sensing element) oriented toward the ground.  All sensors come standard with a conditioning solution in the cap. This conditioning solution is 50% pH 4 buffer and 50% saturated potassium chloride (mixed by volume). The sensor cap should be kept tightly affixed to the sensor body and sealed with common PVC tape when the sensor is not in use. Sensors that are to be returned for shelf life warranty claim must have the original sensor cap and conditioning solution intact to be eligible for warranty replacement.

Avoiding Thermal Shock

For high temperature applications where process liquid exceeds 70°C you will prolong the life of the sensor by avoiding thermal shock. Thermal shock occurs when you rapidly change the temperature of the sensor from hot to cold or vice versa. This rapid expansion/contraction of sensor components can damage internal elements and cause micro-cracking that will accelerate the rate of deterioration. In extreme cases it will crack the sensing element causing a total failure.  To avoid this sensor should be heated or cooled slowly during removal/insertion and cleaning and calibration processes. Consult your Turtle Tough representative for techniques to avoid thermal shock.

Conditioning After Calibration

After the sensor has been cleaned, it must be thoroughly rinsed with deionised water to remove any residual cleaning reagents. The sensor can then be soaked in pH 4 buffer to recondition the pH and reference elements. Some sensors will also require conditioning in saturated potassium chloride if the reference junction has been depleted of the ions in the solid state conductive polymer (typical for clean water applications). Condition the sensor in saturated potassium chloride and/or pH 4 buffer for whatever period of time is required to achieve optimal calibration results.

Please refer to your sensor manual for correct installation, maintenance and use.

Ravensthorpe, Western Australia, 2011.

One of Australia’s largest nickel processing operators were having major problems with getting their pH sensors to last long enough to establish reliable measurement and control. Due to the intense pressure associated with the pressure acid leach process, sensors were only lasting a couple of days . This rapid deterioration required a laborious calibration frequency and did not provide operators with a reliable or stable measurement.

With more than 20 years experience in Nickel ore processing we designed a Turtle Tough sensor specifically for pressure acid leach to interface directly with the existing Yokogawa Analysers. Utilising existing hardware eliminated a major hurdle for the client as they were able to seamlessly swap out the OEM sensor. The pH measurements are now 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.