Clay Application Description
When added to a red firing clay, manganese umber produces an attractive range of browns from speckled to nutmeg to chocolate, depending on your percentage, mixture, and sizing. This beautiful brown clay can then be used for bricks, pavers, roof tiles, and other ceramics.
If your manufacturing processes require, we can provide you with clear instructions for achieving the best suspension liquid for your purposes. To keep shipping costs down, we do not make the suspension ourselves.
- Creating a range of colours from one pigment allows you to meet the needs of a wider selection of consumers without purchasing more products
- Has become the industry standard for achieving brown colouration in ceramics
- Between 9% and 13% irons
- Manganese-to-iron ratio of 4.8:1
- Milled to 98% below 45 micron / 325 mesh
- Naturally contains 46% to 48% manganese
- Available at 42% manganese upon request
- Percentage added to clay in your own processing can be between 2% and 6%, depending on the desired colour and the clay
Manganese umber is a brown ceramic pigment that comes from large natural deposits in Africa. For over ten years, we’ve focused on a particular deposit of manganese dioxide, because it produces consistent and high-quality texture and colour in the finished product.
The brown clay pigment can withstand temperatures up to 1280° Celsius. Some clays become vitreous and unstable at such high temperatures, so use caution. If your clay is stable enough, firing above 1150° Celsius reduces the percentage of manganese umber needed to achieve the desired colour.
African Pegmatite has a large global footprint with over 170 million coloured bricks produced every year from its products.
Manganese Oxide in Bricks
Types of Bricks
There are several processes by which brown clay bricks can be manufactured. Those include the soft mud process, the dry press process, and most commonly, extruded bricks.
The soft mud process involves filling a mould with wet clay for pressing. The moulds should be wetted and/or dusted before filling to keep the clay from sticking. The dry press process is the most popular method of producing refractory bricks. The clay used for dry press only contains 10% water. They are hydraulically pressed, then dried and fired with any desired designs or functional grooves. Extruded bricks or wire-cut bricks are the most common bricks made today. They are made with even drier clay than the dry press process. They are formed in a die and cut using a wire.
Types of Manganese
MnO occurs naturally as the rare mineral manganosite. It is synthesised through the reduction of manganese dioxide (MnO2) with hydrogen, carbon monoxide, or methane. In this form, it is generally used in fertilisers and foods.
MnO2 occurs naturally in large African deposits known as pyrolusite. This is the form of manganese used as a brown brick pigment. It exists only below 1080° C because it will release an oxygen molecule at that temperature. It can also be used to make amethyst glass and to counter the yellow-green of iron oxide in glass.
Trimanganese tetraoxide (Mn3O4) or manganese tetroxide (Mn3O4) occurs naturally as the mineral hausmannite. It can be synthesised by heating manganese oxide above 1000° C and is used in the production of soft ferrites and lithium batteries and during the construction of oil and gas wells.
Brown Brick Pigment
Brown brick oxide is a dense powder that is black in colour, unless it is synthesised, in which case it will be brown. It is insoluble in water, as well as nitric acid and sulfuric acid. Inhalation and ingestion can both cause a disorder of the nervous system.
It takes only a small amount of brown brick oxide to colourise your clays and it will dissolve easily. Above about 5%, it will begin to precipitate and crystallize. This effect is sometimes deliberately achieved to create a speckled look. At 20% brown ceramic oxide or more, it will likely create a metallic surface.
Colouring Clay Bricks
The process of colouring clay bricks is relatively simple. The brown clay pigment is added to the raw materials before firing. The firing temperature, chemical and mineral content of the materials, and the atmosphere inside the kiln will all influence the final colour of the bricks.
The brown ceramic oxide can also be used to apply a superficial colour to the outer surface of the bricks before firing. This method is often used to save on materials and manufacturing costs, though it should be noted that normal wear and damage will reveal the internal colour of the clay brick. This is not a desirable quality in visible exterior bricks like facing bricks or pavers.
Choose the packaging and shipping arrangement that best suits your needs, from small packaging to bulk bags or custom sizes made just for you. We can accommodate virtually any size, from one metric ton to thousands.
We maintain competitive pricing in an effort to win and retain your business for as long as you need us. Our goal is to meet the needs of every customer, including those with special requests and demanding production schedules.
A 15-day general turnaround for manufacturing allows us to get your compounds to you as quickly as possible, so you can keep up with the demands of your business. Contact us to get in touch with a distributor in your area if you don’t have time to wait for materials.
We currently ship to 44 countries across the world and we’re happy to ship to yours, too. The dependable and professional logistics channels we have in place make it easy to offer great pricing and service regardless of your location.
With 48 years as professionals in mining and manufacturing, we have the insight, network, and experience to offer you the very best in quality, service, and efficiency. We’ve been accredited by the ISO 9001 since 2002 and have most recently met the 2015 standard.
We aim to provide the very best materials available to our customers, and become your one-stop shop for colourants, minerals, compounds, and more. Take a look at our general clay and ceramic page to see all the other clay and ceramic products we have available.
If you’d like to become a distributor of African Pegmatite products, get in touch with us and we’ll customise an arrangement with you.