Clay Crucibles

[ Brief Introduction ]

Specializing in the production and sale quality clay crucibles for precious metal analysis.

Kilnsware is a Chinese manufacturer that specializes in the research, production and supply of high-quality fire assay crucibles. We have a complete system of product development, production and quality control. Our crucibles are preferred by various commercial labs across America, Europe, Africa, Australia, and Asia.

Our plant is equipped with 4 automatic production lines and a continuous 35-meter high-temperature kiln. The daily output for the clay crucible is 25,000 pieces, and the annual output may exceed 9 million pieces.

Our new crucible factory is updated to complete in March 2022 and start production soon. Its output of crucibles will be greatly expanded by that time as well.

[ Production Process ]

The clay crucible production line adopts a rolling-pressing process. The refractory clay mud is put into the plaster grinding tool. The machine grinding head presses down while rotating. Then, the clay mud is pressed into a crucible model. Finally, it is sent to the kiln to complete the firing. This fire clay crucible has the same specifications. And the cup wall thickness is uniform. So our crucibles can provide a guarantee for the accuracy of the fire assay.

[ Technical Parameters ]

Besides the models and dimensions of fire assay clay pots listed below, we are also able to produce any model and size of fire assay clay pots according to the customer's requirements.

[ Grouped Equipment ]

A major feature of the fire assay is that it requires a large number of sampling batches. Therefore, the number of crucibles used in each batch will be particularly large. In order to solve the problem of uneven mixing of samples and flux, and the problem of wasting labor time and energy, a crucible mixer designed and produced by Qingdao Decent Group perfectly solves this problem. The picture below is our company's crucible mixer. The sample and flux are rotated in the mixer for 3-5 minutes to mix the sample completely. Contribute to the full melting of the fire test.

In order to solve the problem of taking, placing and transferring the crucible, our specially equipped crucible loading cart can complete the placing and taking from fire assay furnaces or crucible tumbler through simple operations.

We also sell supporting crucible transfer carts, crucible cooling tables, crucible dump forks, steel molds and other equipment.

[ Container Loading ]

[ Fire Assay Method ]

The fire assay crucible is a necessary vessel in the process of analyzing precious metals by fire assay. The fire test method is an ancient and legendary method. For over 3000 years, due to its accuracy in fire assay the content of gold, this method is still the most important test method. The fire assay method is generally divided into three steps:

1. Melting

Crucibles with fire assay flux and the sample is put into the fusion furnace. The lead captures the gold, silver and precious metals in the molten state to form a lead alloy (generally called a lead button). The lead alloy due to the high specificity sink to the bottom of the crucible. The base metal oxides and gangue react with fluxes (silica, borax, and sodium carbonate) to form slags (silicate or borate). Slags floats on the crucible due to its small specific gravity. So the gold and silver separate from the sample.

2. Cupellation

Put the obtained lead alloy in a cupel at an appropriate temperature to remove lead. During cupellation, the lead is oxidized to lead oxide and penetrates into the porous ashtray. Thereby removing the lead in the lead button and a small amount of base metal. Gold silver and precious metals are not oxidized and remain in the cupel to form gold and silver particles.

3. Partition

Use nitric acid to dissolve the gold-silver composite particles to dissolve the silver while the gold remains solid. The obtained gold particles are weighed after quenching, and the gold content can be calculated. The silver content can be calculated based on the difference between the quality of the gold-silver composite particles and the gold quality.