Home Gypsum control The quality of cement is determined by key performance parameters such as setting time and strength, so it is imperative that contributors to these are controlled carefully during the manufacturing process. Better control of gypsum dehydration leads to better control over cement setting time and strength development, providing a marketing edge over competitors. |
|
 |
Dynamic gypsum states occur at temperatures above 105°C when the partial de-hydration of gypsum produces hemihydrate. Anhydrite begins to form about about 170°C. The ratio of gypsum forms is critical to cement performance in use. Changes taking place in gypsum states are not readily apparent because to date there has been no way to monitor the phases until it's too late and customers complain of poor performance. COSMA continuously monitors and reports all three gypsum states from a cement sample stream. For the first time, operators have a live picture of these dynamic states and are able to manage the process to produce a consistent product. |
| Financial benefits result from the improvements in product quality, especially in competitive markets where the customer demands the best performance characteristics, consistently. Setting time prediction is the next step after controlling the gypsum dynamics, which has many mineralogical contributors; free lime, clinker minerals and, of course, gypsum states. COSMA provides accurate data on the content of all of these minerals and, over time, correlations between them and setting times enable a control regime to be developed and implemented based on FCT's predictive control model. |
|
 What COSMA can do for you
|
|
Limestone |
|
| Regulations around the world permit the addition of up to 5% limestone in Portland cement. In Europe and North America limestone has been used successfully for decades as an extender in cement, providing equivalent performance to cements without limestone. Environmental benefit from the use of limestone in cement is a key component of the cement industry's commitment to a reduction in the level of greenhouse gas emissions by the year 2020. Financial benefits also flow from the substitution of clinker in the cement milling process, as less costly limestone is used instead of valuable clinker. |
 |
Sold out plants enjoy even more significant benefit as the clinker substituted by limestone is available for additional cement production, maximizing sales whilst demand remains high. The challenge for cement producers is to maximize the value of clinker production by working as close as possible to the prescribed limit of limestone addition. Traditional control by infrequent spot samples taken from the process for laboratory analysis, which measures the chemistry rather than the limestone mineral itself, do not permit tight control. Thus a target level of addition well below the limit must be adopted to provide large but costly room for error. |
|
|
||
|