Glass melting efficiency, glass quality and production cost; they are first of all determined by the glass batch composition. It is often overlooked that (even small) changes in the batch can perfectly generate technical and operational advantages as well as significant cost saving benefits.
Especially for insulation wool, container glass and float glass production, cullet is usually one of the most important raw materials. First of all, cullet improves significantly the melting process e.g. energy consumption reduction (about 2,8% - 3,0% per 10% increase of cullet), replacement of primary raw materials (operating costs reduction),CO2 emissions, waste disposal charges reduction. A major disadvantage of cullet is the contamination risk.
Contaminated cullet usually results in glass defects, glass breakage and/or a global glass quality decrease. Due to this extreme importance of the cullet quality, cullet quality control procedures and sampling plans must be well developed at the cullet treatment plant as well as at the glass plant so that the quality of the cullet lot can be guaranteed at the determined probability for a correct QC judgement.
If the amount of csp (i.e. ceramics, stones porcelain) pollution in a cullet lot is e.g. twice the maximum acceptable level, what is the probability for your quality control procedure that this non-conform lot will be accepted? Using our in-house developed statistical calculation programmes, we'll give you a detailed answer to this kind of fundamental questions and we precisely calculate how your procedure must be optimised to reduce this risk according your quality objectives.
For cullet treatment plants and glass plants familiar with 6 sigma quality objectives, a 95% reliable (≈2σ) cullet QC is a must. However, our calculations prove that probabilities of making quality control errors are usually much higher, resulting in unacceptable producer's and consumer's risks.
Interested in an assessment of your cullet quality procedure? Interested in improving your cullet quality procedure? According your quality objectives, we can elaborate a fair, transparent, verifiable and statistical relevant cullet quality control procedure for glass recycling companies and for glass manufacturers.
Checking for impurities... it's basically about statistics and probabilities of finding impurities, but... gambling on product quality must be excluded anyway!