A Guide to Getting the Most from your Outsourced Laboratory Testing Service

Most manufacturing units face issues like dealing with masses of unknown slag material deposited in furnaces and kilns, or the absence of in-house instrumentation to conduct periodic QC or QA inspections.

Inorganic mineral, ceramics, and refractories manufacturing units across the world are using the services of Washington Mills’ Laboratory Services Group for different types of analyses, from simple sieve analysis and loss-gain on ignition (LOI), to complex X-ray fluorescence (XRF) and X-ray diffraction (XRD). Given the range of test methods and numerous acronyms related to them, it is quite a challenge to understand the test environment.

Using the tips provided below, companies can derive maximum benefits out of outsourced laboratory testing services.

The first step towards outsourcing testing services is to understand that there can never be too much information. Although technicians and chemists at Washington Mills are capable of handling complex testing propositions like mysterious slag depositions, it is better to provide maximum information to them while submitting the sample for testing.

Armed with comprehensive information, the technicians can figure out the appropriate test or series of tests required for a particular sample. A few key points to consider while submitting the sample for testing include:

  • Is the requirement for general chemical composition information or specific phase details, or a combination of both?
  • Is the presence of moisture a concerning factor?
  • Is the size of the particle a concern?
  • What type of material is it; calcined or virgin?
  • Are there any specific contaminants causing concern?

Being prepared with an answer to all these questions can help the testing technicians conduct quick and efficient testing of the sample. As well as these questions, the lab technicians may ask for additional details about the sample being submitted.

Importance of General Understanding

It is not necessary to be an expert in various analysis methods in order to coordinate with a testing lab. All that is needed is a general understanding of the testing procedures so that one can assess the most suitable methods for the requirement and evaluate the results obtained from these tests.

Various types of testing services including instrumental, analytical and physical for a variety of materials, including refractory raw materials, ceramic powders, cement, minerals and many more, are provided by the Washington Mills’ Laboratory Services Group.


Based on the type of information required, either X-ray fluorescence (XRF), X-ray diffraction (XRD), or both can be used. The chemical composition of a material can be identified with XRF analysis. For instance, XRF analysis on aluminum oxide may reveal 85% of the oxide and traces of sodium oxide, titanium or even calcium. Comprehensive quantitative analysis of the constituents of a sample can be conducted via XRF analysis.

If companies require sample detains in addition to the XRF data, they can use XRD analysis. The crystallography of materials present in the sample can be determined by XRD. For instance, XRF analysis can only show that a sample contains 25% silica and 75% alumina, it cannot identify whether they are present in different phases or are combined.

XRD reveals that the material is not just silica and alumina, but aluminium silicate. In most cases, XRD analysis complements XRF analysis, but it can be used as a separate test as well. Although companies are already aware of the materials contained in their products, they often use XRF or XRD to detect any compositional changes after firing.


Analytical testing procedures often involve sample preparation, moisture content, loss on ignition (LOI) and total or free carbon analysis. Samples of 2 x 2 inches can be reduced to small pieces or very fine powders by Washington Mills.

For further testing, the sample may be processed into wafer, pellet or bead form depending on the type of material being tested. Further processing of a sample can be done using LOI to burn off any organics present in the sample or moisture that was bound during moisture analysis, or for conversion of free metals into their oxide form.

During moisture analysis, the weight of the sample is determined before placing it in an oven heated to 110 °C for about an hour. After this, the sample is weighed again for evaluating the loss in weight. Materials that contain carbon like boron carbide or silicon carbide can be analyzed by total and free carbon testing.

The elemental state can be identified by free carbon analysis, while the free carbon and the combined carbon can be identified by the total carbon analysis. The value of free carbon is deducted from the total carbon value, and this value is multiplied by a factor for deriving the percentage of silicon carbide.


The physical characteristics of the material like particle size, density and strength can be measured at the laboratory. The most commonly used instrument at Washington Mills is the Coulter particle size analyzer, owing to its ability to provide reliable results even for smaller particle sizes, and for its compliance with most national standards. Tap density or bulk density tests are conducted to measure sample density.

Bulk density testing for coarser material is conducted by loosely filling the sample material within a test vessel. For finer particles, tap density testing is conducted by tapping a sample down the testing vessel. Mechanical strength can be measured through friability testing procedures that reconstruct scenarios where the end product is required to remain sturdy. Determination of parameters like specific gravity, magnetic content and microhardness can be done via additional testing procedures.

Finding the Right Partner

Irrespective of the outsourcing lab testing needs, whether they are simple or complex, or one-time of regular or ongoing QA assignments, identification of the right partner is crucial to the success of the company. A company needs to evaluate the expertise and capabilities of various companies and identify the ones that suit their requirements.

Some companies may require a large lab facility that is ISO certified and can provide a variety of testing methods. For such requirements, companies run into higher costs and the turnaround times may be longer. Sometimes a smaller lab may suffice for specific testing requirements, and the costs may work out much cheaper.

The QC of a company’s manufacturing operations can be taken care of by the Washington Mills Laboratory Services Group. By outsourcing lab testing procedures, costs can be reduced, and high quality of products can be ensured.

The turnaround time for tests conducted at Washington Mills is generally 1-2 weeks, and they also offer premium services for quicker turnaround requirements. Specific tests for ceramic and refractories manufacturers are handled by the experienced and knowledgeable technicians at Washington Mills. They also provide customized testing programs to companies working on a case-by-case basis.

This information has been sourced, reviewed and adapted from materials provided by Washington Mills.

For more information on this source, please visit Washington Mills.


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