Uses
MoistScan® online microwave moisture analysers find ever increasing use in production and processing plants where moisture content and control is critical to efficiency, quality as well as health and safety. Production managers solve process challenges with MoistScan® analysers in the following areas.
Increase Plant Efficiency
Whether removing moisture from product or adding just the right amount, it is no secret that the wrong amount of moisture can severely impact on process efficiency.
Removing moisture
Drying or calcination operations are amongst the most energy intensive processes and a major focus for plant managers to glean gains in efficiency. Online moisture analysis of the material being dried can be used for manual or automated control of dryer parameters to optimise resident time of the material in the dryer. Irrespective of the type of drying equipment, be it shaft furnaces, rotary kilns, multiple hearth furnaces or fluidised reactors, the importance of accurate moisture monitoring and control cannot be overstated. In most popular drying or calcination processes, MoistScan® is typically employed at either the entry or exit to the dryer or calciner. The information from the MoistScan® is used in a PID control loop enabling feed-back or feed-forward control.
Pelletising and Sintering
Accurate moisture control is critical for green pellet formation during the pelletising process. Promoting ideal pellet agglomeration conditions assisting in pellet strength and reducing returned fines from the furnace while ensuring optimum water usage. In addition, the blast furnace is not taxed with more moisture than necessary, improving energy use and adding value including better use of raw materials. combining agglomeration with thermal energy is increasingly being used as a method of value adding.
Improve Product Quality
One of the most popular uses of MoistScan® is for quality control. In engineering and manufacturing, quality control is increasingly important as customers become more discerning and product specifications become tighter.
In many processes the amount of moisture is critically important. Too much moisture or too little moisture can result in an end-product that is out-of-spec. The ramifications of this are varied. In the resources industries it can result in payment penalties or in the moist dryer case result in rejection of a shipment. In the food industries the incorrect amount of moisture has implications for product shelf life and consumer health.
The MoistScan® range of online moisture gauges will accurately determine the amount of moisture in products for sale under stringent specification with respect to total moisture levels. MoistScan® is highly accurate with repeatable results. By implementing online moisture analysis Quality Control Officers have a very useful tool.
Accurate Dry Tons Accounting
Dry tonnage reconciliation or metallurgical accounting as it is often referred to, as increasingly being implemented in pit to port mining operations throughout the world.
MoistScan® technology enables calculation of dry tonnage as opposed to wet tonnage where only a traditional belt scale is employed.
Typically, MoistScan® units will be installed along with belt weighers at critical measurement points along the value chain. This is especially the case where change of ownership of the product occurs or where individual business units within a single integrated operation institute measure productivity.
Bulk Materials Handling
A common process challenge for which MoistScan® analysers are purchased is to reduce problems associated with the conveyance and processing of bulk materials. Typically, problems arise when water is added to materials, particularly materials that are high in fine particles. Minerals that have significant clay content are cases in point as particles tend to agglomerate at higher moisture levels and become sticky. This causes problems at transfer points and in chutes and hoppers where hang-ups or blockages can occur. Better monitoring and control of water addition can significantly reduce plant down-time by eliminating blockages.
Where dewatering is required such as coal wash plants and mineral concentrators, MoistScan® is used in association with dewatering equipment such as centrifuges, vacuum filters and other solid-liquid separation technology.
Water addition commonly begins at the mine where it is applied to suppress dust, starting at the face and at transfer points, throughout its transport out of the mine. Consequently, material arriving at the preparation plant can be quite wet.
Both economic and practical consideration dictates that water must be removed to a predetermined level after it has been processed and before it is dispatched. Often this level of moisture is critical. Too much moisture may cause transportation and safety issues as well as result in payment penalties. Too little moisture may result in quality reduction and loss of saleable yield. In this regard online moisture analysis can play an important part in dewatering and drying.
Improve Health & Environment
Ever increasing environmental requirements around mining and processing operations with special focus on dust suppression, MoistScan® analysers have become a necessity for monitoring ore moisture.
MoistScan® is traditionally incorporated into a site dust management strategy where multiple analysers are used to monitor the moisture level of material transported from pit-to-port. The percentage moisture reported by the MoistScan®’s are compared to known dust extinguishable moisture levels (DEM’s) for each product. Where the moisture in the burden is lower than the DEM water is added to the belt via automatically controlled spray bars.