Loss on Ignition (Ceramic)
Compute the loss on ignition (LOI) of a ceramic raw material, LOI = (mass before − mass after ignition)/mass before·100%, the mass lost during heating at high temperature. It corresponds to the release of combined water (clay minerals), the burning of organic matter and the decomposition of carbonates (releasing CO₂). A high LOI indicates much clay/volatile matter and requires care to avoid defects (bubbles, cracks). Enter the mass before and after ignition.
Result
—
Perda ao fogo (cerâmica)
A perda ao fogo (PF) PF = (massa antes − massa após calcinação)/massa antes·100% mede quanto uma matéria-prima cerâmica perde de massa ao ser aquecida a alta temperatura (tipicamente ~1000 °C). Não é só a água — são três fenômenos que liberam massa na forma de gases: a saída da água combinada quimicamente nos argilominerais (a caulinita, por exemplo, perde ~14% ao se desidroxilar); a queima da matéria orgânica presente na argila (raízes, húmus — que viram CO₂); e a decomposição de carbonatos como a calcita e a dolomita (CaCO₃ → CaO + CO₂↑), que pode liberar muito CO₂. Conhecer a PF de cada matéria-prima é essencial por vários motivos: ela determina a retração e a porosidade finais (mais voláteis saindo = mais poros e retração); exige cuidado na queima (se os gases saem rápido demais, antes de a peça estar permeável, causam bolhas, inchamento (coração negro) e trincas — por isso a curva de queima tem patamares); e afeta o balanço de massa da formulação (uma matéria-prima com 20% de PF contribui com menos massa final do que aparenta). Argilas plásticas e calcários têm PF alta; o quartzo e a maioria dos fundentes, baixíssima. A PF é uma das primeiras análises de caracterização de qualquer matéria-prima cerâmica. Informe a massa antes e após a calcinação.
Related Tools
Drying Shrinkage (Ceramic)
Compute the linear drying shrinkage of a ceramic piece, DS = (L_wet − L_dry)/L_wet·100%, the size reduction as it loses the forming water before firing. The water that separated the clay particles evaporates and they draw together. Excessive or non-uniform drying shrinkage causes cracks and warping — which is why drying is slow and controlled. Enter the wet and dry lengths.
Stack Heat Loss (Siegert)
Calculate the heat loss through the exhaust gases by the Siegert formula, loss = K × (T_gas − T_air) ÷ CO₂, from the fuel factor K (~0.5 for natural gas, ~0.6 for oil), the gas and combustion air temperatures (°C) and the CO₂ percentage in the gases. The result, in %, is the largest energy loss of a boiler or furnace — the heat escaping hot through the stack. Lowering the gas temperature (with economizers and preheaters) and adjusting the excess air (which dilutes CO₂) minimizes this loss. The combustion efficiency is approximately 100% minus this loss. Enter the K factor, the temperatures and the CO₂.
Vitrification Degree (Ceramic)
Estimate the vitrification degree of a ceramic, VD = (1 − WA/WA_green)·100%, comparing the current water absorption with that of the green (non-vitrified) material, as a measure of how much the glassy phase filled the pores during firing. Vitrification — the formation of molten glass that seals the pores — densifies the piece, lowers absorption and raises strength and impermeability. It is what turns porous clay into vitreous porcelain. Enter the current and green water absorptions.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.