Chemical Processing 101: Screening

What Is Screening?

In the context of chemical processing, screening is the process of segregating materials and classifying them into different sizes or grades. There are two types of screening: dry screening and wet screening.

Dry screening entails screening materials in their naturally mined state by way of vibration. The processor filters the material through physical screens, wherein particles of a certain size will pass through openings of a certain size. The smaller the particle size needed, the smaller the openings will be, which can make the screening process more difficult. This process can involve many screens for multiple distribution piles.

Wet screening, on the other hand, involves adding water or another liquid to the mixture as an extra step in the process. Depending on the material, this allows the screening machine to separate and process the materials more efficiently. Wet screening is typically used for processes that involve finer feed material, or in cases where the material has a high moisture content that makes it more difficult to dry screen. Sometimes, desiccation is required at the end of the process in order to remove liquid used in the wet screening process. Afterwards, the material can be further processed or handled. Howard Industries offers a multitude of services to follow up the screening process such as packaging or warehousing.

What Is The Purpose of Screening?

Sometimes, manufacturers use the screening process as a form of quality control—to decide whether or not materials are suitable for the next step of their manufacturing process. For example, the mining industry may use screening equipment to separate asphalt into various sizes before mixing it into concrete. Material that does not pass the screening process may be taken and re-manipulated—i.e. being crushed or ground before returning to the screening process.

Other industries use screening to separate different materials from each other. For example, recycling plants must separate trash from recyclables. The screening process may also be used in factories for maintenance and cleanliness purposes. Screening can help gather the very fine particles of unwanted materials, preventing them from collecting on other machinery and avoiding various hazards or accidents.

What Tools Are Used For Screening?

Screening equipment is differentiated by the type of materials being separated, the size of the materials, and other factors manufacturers might require for processing. The most common application of screening is to segregate materials into different size groups. Different types of screens are used in vibrating machines to perform the job.

There is also screening equipment specifically tailored for wet screening. Depending on how the material will be used after the screening process, some equipment will also include dewatering and dedusting mechanisms.

Factors to note when considering what screening equipment to use is the initial size of the material, the final particle size needed, and whether a single deck is adequate, or instead a multiple deck design should be used in the process. Examples of screening equipment include:

  • High-frequency vibrating screeners
  • Grizzly screeners
  • Trommel screeners
  • Tumbler screeners
  • Sieve bend screeners
  • Banana screeners

How Can Howard Industries Fulfill Your Screening Needs?

Howard Industries offers multiple deck screening, sonic screening, and air separating. With the ability to set-up multiple decks on our screeners, we can separate your materials by size, all in one step. Whatever your material, and whatever your quantity, you can count on us to deliver. Additionally, Howard Industries can help you further process your materials. We can fulfill all your chemical processing needs, whether it be drying, mixing, blending, or packaging! Contact us today to learn more.