Preparation And Application Of The Porous Structural Powder By Acid-etched On Surface Of Artificial Granite Waste

With the rapid development of stone industry,all kinds of artificial stone constantly appeared and gradually been widely used.Artificial granite is an artificial decoration stone made in natural marble crushing material and stone powder and through vacuum mixing,shaking forming,high temperature curing and other processes.To explore the pore formation law of acid-etched GW surface,The porous material was then used as the base,Nickel and copper plating were deposited on their surface by chemical plating,The GW/Ni and GW/Cu electromagnetic shielding composites were prepared,The bonding mechanism and electrical conductivity of composite materials and electromagnetic shielding were studied;The PLA rods were modified by mixing GW powder with different acid etching times with polylactic acid(PLA)for dense refining and injection molding,The surface structure and mechanical properties of polylactate splines with different GW content were also studied.The specific work is as follows:1.First,the acid etching method was used to treat the waste granite waste residue,A porous powder with a high specific surface area was prepared;studies have shown,The surface of the acid-etched granite waste residue contains active groups such as hydroxyl group;With the increasing time of acid etching,The total specific surface area of the granite waste slag is increased from 4.707 m²·g^-1to 79.003 m²·g^-1,The maximum specific pore volume was increased from 0.00141 cm²·g^-1to 0.0092cm²·g^-1.Acid-etching calcite and dolomite have a certain regularity,H⁺first reacts with particles on the calcite(104),Reacting with the dolomite again,Then,the particles arranged on the crystal surface of the same calcite(110)reaction,Gradually form a hole structure on the surface of the granite waste slag;After 20h of acid-etching,The calcite and dolomite in the granite waste slag are completely destroyed and decomposed.2.Sselectively deposited metal layer composite powder was prepared on the surface of 20 h by chemical nickel/copper process.After study,the porous active site of the surface can be bonded with catalytic particles(Pd²⁺,Ag⁺)for catalyst after chemical nickel/copper reaction.In the frequency range of 0.5 to 18 GHz,the electromagnetic shielding efficiency of GW/Ni composite is higher than 30 d B,and that of GW/Cu composite is higher than 50 d B.With increasing chemical plating time,the resistivity of GW/Ni composite was reduced from 73%to 15.1%and that of GW/Cu composite from 6.26%to 2.29%.3.The GW/PLA composite specimen was prepared with acid etched GW powder after dense refining and injection molding.The loose chain arrangement of pure PLA specimens is easy to produce activity and low crystallization.After adding GW into the substrate,when the GW content is low,the packing particles are not evenly distributed inside the matrix,and the PLA macromolecules can easily reunite;When the GW content increases from 15%to 30%,the agglomeration phenomenon is greatly reduced,and the GW powder particles and PLA macromolecules are closely bound and are evenly arranged.At this time,the mechanical properties,thermal stability and crystallinity of GW/PLA composite specimens were significantly better than those of pure PLA specimens.Among them,the crystallinity of GW/PLA composite specimens with 30%GW content was 30.4%,and the tensile and bending properties were 65.4 MPa and 1601.2 MPa,respectively.Compared with pure PLA specimens,the tensile and bending properties were 36%and 75.6%higher than pure PLA specimens,respectively.