Glass and Ceramic

In the realms of glass and ceramics manufacturing, the necessity for efficient dust and fine particle separation is underscored in several critical processes, vital for maintaining product quality, operational efficiency, and environmental standards.

During the treatment of recycled glass, removing fine particles and dust is essential to ensure the purity of the cullet, thereby reducing waste and enhancing the quality of new glass products. Similarly, in the glass bottle manufacturing sector, the drying processes demand dust management to prevent contamination and ensure the integrity of the finished products.

In ceramics production, spray drying processes are crucial for creating uniform, fine powders for construction ceramics and advanced applications, ensuring consistent material quality and reducing defects. The role of powder separation becomes increasingly critical in the ceramics sector, particularly in spray drying applications where the yield of recovered powder directly influences production efficiency and material utilization, reducing waste. 

Furthermore, during the grinding of ceramics, including ceramic coatings like borosilicate glass, capturing and recovering the fine dust emitted into the factory environment is vital for both economic reasons and workplace safety.
 

Recovery of Spray Dried Ceramic Powders

Spray drying is widely used in the production of ceramic powders. The process starts with the preparation of the ceramic slurry which is then fed to the Spray Dryer for atomization into fine droplets. They are introduced into a drying chamber where they encounter hot air (typically heated to a temperature ranging from 150°C to 300°C). As the droplets travel through the drying chamber, the solvent (usually water) evaporates rapidly due to the high temperature. This results in the formation of dry, spherical ceramic powder particles. 

A part of the dried product (the coarser powder) settles at the bottom of the chamber and is discharged through an airlock system. The finer particles that may escape the primary collection are exhausted with the hot air and are further separated using cyclones. Finally, there’s typically a water scrubber system for final emission control.

The collected ceramic powder is usually free-flowing and can be easily handled, stored, or further processed. Typically the powder has high hardness and is erosive. 

Clients require durable cyclones to minimize product loss, reduce OPEX in wet scrubbers, and ensure long-lasting performance. 

Advanced Cyclone Systems (ACS) offers an optimized cyclone solution with extremely high separation efficiency to maximize powder collection. In addition, the system is designed considering optimized geometries for each application and an operating range to maintain adequate velocities and pressure drops, while being built with the best materials to increase erosion resistance and, therefore, equipment life.
 

Powder Recovery after Fine Grinding (Ceramic Frits or Enamel powders)

A ceramic frit is a vitreous (glass-like) material that is created by melting various raw materials (such as silica, alumina, fluxes, and colorants) and then rapidly cooling them to form a glassy, solid granule or powder. The frit is typically applied as a glaze on ceramics or as part of the process to create enamel. It acts as a base material that, when fired, forms a smooth, glossy surface on ceramics or other substrates.

Enamel is also a glassy coating that is fused to metal surfaces. It is often made from finely ground glass (which may include ceramic frits) mixed with other materials and then applied to the metal surface. The object is then fired at high temperatures, causing the enamel to melt, flow, and fuse to the substrate. It is commonly used as a protective and decorative coating on metals like cast iron (as in cookware), steel, and even on glass objects. It provides a durable, non-reactive, and often colorful finish.

In the final process of preparation of the Ceramic Frits and Enamel glass-like powders, often a step of fine grinding is needed to get the right particle sizes distribution for the coating. Typically, fluidized bed jet mills or micronizers are used due to their ability to produce fine and uniform particle sizes, reduced contamination and efficiency in processing hard materials. These mills offer precise control over the milling process, ensuring that the frits have the desired properties and color for their intended application. Usually it’s a batch process, where many formulations can be produced.

The market demands that the micronized powder collection system must be versatile, to be capable of handling different formulations,  highly efficient, to avoid losses of valuable products, easy to clean while avoiding cross contamination and wear resistant to be capable of handling hard and erosive powders.

Therefore the separation is usually done in two steps: the first one, by means of a cyclone system, easy to clean, to provide the Product Recovery and the second one, usually done by a bag filter, serves the purpose of emission control and sometimes offers 2nd grade product (cross contamination allowance). Typical process flow diagram can be seen in the following figure:

Advanced Cyclone Systems (ACS) offers an optimized cyclone solution (hurricane system) with extremely high separation efficiency, to maximize powder collection. In addition, the system is designed considering optimized geometries for each application and an operating range to maintain adequate velocities and pressure drops, while being built with the best materials to increase erosion resistance and, therefore, equipment’s lifespan. Many times the hurricane cyclones can be lined internally with special materials to withstand higher wear rates.