Last week Munich hosted one of the largest ceramic exhibitions: Ceramitec 2018. From 10-13 April the international ceramics industry gathered around the exhibition, which was, in general terms, really successful. In case you couldn't attend, we were there to be able to show you.
When it comes to the use of ceramic additives, we must be 100% sure that the one that we are using is the best for their production process. We have talked about different ways to optimize ceramic production processes in several blog articles and we even wrote a blog post on the benefits of using additives in a brick production. However, we have received many questions about how additives can affect a manufacturing process. We will try to answer all of the questions as well as we can. This month's question is: "will the additive block my extruder if there's a production break?"
New aesthetics aligned with new technical requirements in the extrusion of ceramic bodies are demanding a new approach when it comes to additives’ requirements. In the past, lubrication and proper rheology were highly appreciated, but today there are other properties that should be taken into consideration if defects such as cracks, laminations, scumming, etc. can’t appear along the process, mainly due to the higher technical requirements of the raw materials.
Cracking – in whatever stage of production – is a major loss issue faced within all types of clay manufacturing and the reduction/elimination is paramount for increased profitability and yields.
Large Structural Brick
Brick types vary from thin brick to face brick to structural through the wall units. Thin brick allow for less weight and less costly installation. Face brick provide some insulation and are practically maintenance free for the lifetime of a building. Structural clay brick provide greater insulation, more protection from the elements, and the appeal and durability that have always made clay brick a desirable building material. The manufacturing of large structural clay brick presents challenges to brick makers in two of the critical processes involved in brick making: extrusion and drying. In this blog post we will focus on how to avoid breakage in the extrusion part of the manufacturing process.
In the past, potters used to “age” their moist clay in damp cellars or storage containers for years to achieve the effects that are now possible after a few minutes of clay mixing.
The raw materials used to make bricks are the most important part of the process. The quality of the brick and the success or failure of the brick plant can often be traced to the raw materials. The planning and implementation of a raw materials program is the backbone of a well-run brick plant. Brick plants are often built in close proximity to the primary raw materials to be used for decades. The quality and consistency of these raw materials normally vary throughout the mine property. When the characteristics of some mined materials are too far out of specifications it may be necessary to avoid these raw materials thus reducing the raw material reserves. Some of the characteristics and some of the ways to optimize the usage of raw materials are described below.
In today’s heavy clay market there is becoming a push for more product in faster lead times. This need is putting extra pressure on manufacturers especially to increase throughput times. Although kilns and sometimes driers can be the bottleneck, there is added pressure on the moulding equipment to produce clay products quicker.
Why does an efflorescence appear?
In chemistry, efflorescence is defined as the migration of a salt to the surface of a porous material, where it forms a coating. The essential process usually involves the dissolving of an internally held salt in water. The water, with the salt now held in solution, migrates to the surface, then evaporates, leaving a coating of the salt. These efflorescent salt deposits tend to appear at the worst times, usually about a month after the building is constructed, and sometimes as long as a year after completion.
Before bricks and tiles can be fired the majority of water used in its moulding needs to be removed from the clay product. Any excess residual water or moisture left in the article as it enters the kiln to be fired will be removed very quickly leading to major problems such as blow out, warpage or in the extreme – as has been seen on numerous occasions – to explode causing serious damage to the kiln and production.