This invention generally relates to a mixing at least one material with at least one other material within an in-line mixing device. In one example embodiment methods, apparatuses, and systems are described to treat, reuse or otherwise remediate dredged or raw material from bottom sediment or other sources through the mixture of raw material and another material such as a hardening agent into a homogenous material for contamination remediation, use as construction materials or other uses.

An agitator for a gypsum wallboard mixer is provided and includes a circular disc with an upper surface, a drive shaft extending vertically from the upper surface, a lump ring secured to the upper surface, the lump ring being provided in a plurality of spaced, adjacent arcuate segments.

A three-dimensional printing head including a dynamic mixer comprising a mixer casing, which delimits a mixing chamber, a supply inlet configured to supply the mixing chamber with a mineral composition and a discharge outlet; and an injector for injecting a building material admixture in the mixing chamber. The injector includes a tubular injecting member being flexible and having an injection outlet, the tubular injecting member being elastically deformable between a first state in which the tubular injecting member is configured to allow a flow of the building material admixture through the tubular injecting member and towards the injection outlet, and a second state in which the tubular injecting member is configured to prevent a flow of the mineral composition from the mixing chamber and through the tubular injecting member.