Dynamics of the dry premixing stage of a hydrophobic formulation and potential implications on the wet granulation process

Mota-Aguilar, David A.; Velázquez, Carlos

doi:10.1016/j.powtec.2015.07.048

Cited by 5 publications

(3 citation statements)

References 34 publications

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“…A binder-treated process typically starts with a dry mixing stage (i.e. dry premix), in which the principal objective is to breakdown the ingredient layers and to prepare the blend for further processing [15]. The adsorption between the powder particles at this stage is dominated by Van der Waals forces F vdw (according to Rumpf [16] theory: F vdw ≈50 F e , so the electrostatic force of F e can be neglected).…”

Section: Resultsmentioning

confidence: 99%

Process analysis of binder treatment on iron-based alloy powder

Zhang

Wang

et al. 2017

Powder Metallurgy

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Binder treatment technology is a widely used method of bonding fine powders to coarse particles using a binder liquid. In this paper, binder treatment experiments were carried out for binary Fe-C mixture and multicomponent mixture (alloy powders exceeding 15 wt.%). The differences of particle size distribution and microstructural of conventional mixing and binder treatment mixing in Fe-C mixture were compared, and the fine particles were evenly bonded to the coarse iron particles surface and preferentially filled into the pits after binder treatment. The physical properties of the multicomponent mixture after binder treatment were improved, the flowrate and fine particles adhesion ratio achieved 30 s/50 g and 96%, respectively, and the segregation was obviously reduced. Further, the phenomenon of small particles bonded to large particles was explained by capillary force and snowball effect. Meanwhile, the theory that small particles migration caused by spontaneous capillary flow during drying and consolidation was proposed.

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Section: Resultsmentioning

confidence: 99%

Process analysis of binder treatment on iron-based alloy powder

Zhang

Wang

et al. 2017

Powder Metallurgy

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“…In the process of bonding, the iron powder and the other alloying elements were first added to the mixing cylinder and premixed for 45 min. In this stage, the ingredient layers were broken-down [22]. At the same time, 800 mL of n-heptane and trichloromethane (3:1) mixed solution was added to the prepared binder.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

Thixotropic properties of multi-functional binder and compaction behaviour of the low alloyed binder-treated powder

et al. 2018

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A new multi-functional binder with adhesive and lubricant effect was designed, and the thixotropic properties of the binder components and the resulting binder, the adhesive effect and compaction behaviour of the binder-treated powder were investigated. The results demonstrate that the thixotropic components in the binder are polyethylene wax and microcrystalline wax. With the increase of polyethylene wax content, the critical solid-liquid shear stress of binders decreases gradually. The main lubrication components in the lowpressure and high-pressure stages during the compaction process are found to be polyethylene wax and microcrystalline wax, respectively. The fine metal or graphite additives are effectively bonded on the surface of iron particles and filled in the pits. The green density reaches 7.25 g cm −3 at 600 MPa when the content of polyethylene wax is 30%. From 400 to 750 MPa, the content of polyethylene wax corresponding to the minimum ejection pressure decreases from 20 to 0%.

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“…Powder granules are produced from a suspension of solid particles that agglomerate in a liquid phase [8][9][10]. The surface of the particles and the binding liquid must be of identical polarity [11][12]. The liquid binds the particles together by a combination of capillary pressure, surface tension, and viscous forces to a point where permanent solid bridges are formed after evaporation of the solvent [13][14].…”

Section: Introductionmentioning

confidence: 99%