Process Sensors (Europe) Limited
Process Sensors

 Applications - Minerals

    Why Measure?
On-line measurement of moisture in minerals affords greater and more reliable information than off-line measurement and additionally saves time and effort. There are many reasons for measuring moisture content; moisture levels indicate impurity levels, moisture impacts process ability, for example the crushing operation of Calcium carbonate, also the control of the blast furnace in steel processing. Moisture can affect the quality of the end product, for example, excessive moisture in coke will affect the chemistry of the molten iron leading to a lower grade of steel. Moisture content impacts safety when transporting minerals as certain ores, e.g. iron and nickel liquefy at relatively low moistures.  
 

 

Mineral Applications

Alumina Copper concentrate Gypsum Soda ash
Bauxite crushed coal Hydrated lime Sodium Chloride
Bentonite Crushed coke Iron ore Talc
Boric acid Dolomite Limestone  Titanium dioxide
Calcium Carbonate Ferrite powder Peat moss Sulphur
Calcium Oxide Fibre glass Perlite Zeolite
Cement fly ash/potash Sand  Zinc Oxide
Clays & Ceramics Glass cullet Sinter  

Sensor

The MCT 360 measures moisture in minerals from crushed ores to fine powder concentrates. NIR (Near Infrared) technology is ideally suited to on-line moisture measurement as it is non-contact, safe, non-destructive and unaffected by changes in density, the latter being an issue with radiofrequency and microwave technologies. The NIR moisture sensor is housed in a robust cast aluminium enclosure which can be mounted outside providing the gauge is protected from direct sunlight and high pressure hosing with water. The moisture gauge is supplied with an air purge tube surrounding the viewing window to keep it dust-free, but for installations in very dusty environments an Atex rated NIR sensor, the ATEX22 -MCT 360 is recommended. In cases of high temperature installations, the MCT 330-HD is an alternative option to the MCT 360 with a vortex cooler which negates the requirement for air or water coolant up to 65 degrees Celsius. The MCT 660 lab instrument is available for off-line use.

Accessories
Product loss sensors are available for discontinuous product flows preventing measurement update when product is absent. (Note that a good bed depth of product is essential when product is running, intermittent gaps will cause erroneous readings). An alarm board is available that will enable a visual or audible alarm if an instrument fault condition occurs or if the moisture reading lies outside of the specified operating range.  A heat blanket can be fitted inside the gauge to ensure the internal temperature of the gauge doesn’t drop below the minimum operating temperature, and the addition of a vortex cooler and cooling panel will keep the gauge performing under ambient conditions of up to 80°C. The enclosure is IP65 rated, and as such, is dust and splashproof, but if the gauge is to be mounted outside it will benefit from a cover to protect it from driving rain, snow or direct sunlight.


Gauge outputs, Operator Interface & Display

Up to 3 x 4-20MA or 0-10V
RS232 or RS485
Optional bus
Optional Operator Interface and display unit

The measurement
Moisture measurement is most accurate in crushed ores and concentrates with a narrow particle size range and colour variation. Some black minerals are extremely NIR absorbing whilst measurement can still be achieved the noise level is high so the signal requires damping. Measurement accuracy can be as high as +/- 0.1% with light coloured finely powdered product.

 

Sensori di processo Italia China