Method of treating magnesium oxysulfate or magnesium oxychloride article with water soluble phosphate solution

• US 20190308914A1
• Filed: 04/06/2018
• Published: 10/10/2019
• Est. Priority Date: 04/06/2018
• Status: Abandoned Application

• Current Assignee: Xianghua Kong
• Original Assignee: Xianghua Kong
• Inventors: Kong, Xianghua
• Application Number:
  US15/947,392
• Publication Number:
  US 20190308914A1
• Time in Patent Office: Days
• CPC Class Codes: C04B 14/18 Perlite
• CPC Class Codes: C04B 14/304 Magnesia
• CPC Class Codes: C04B 18/26 Wood, e.g. sawdust, wood shavings
• CPC Class Codes: C04B 2111/28 Fire resistance, i.e. materials resistant to accidental fires or high temperatures
• CPC Class Codes: C04B 22/16 containing phosphorus in the anion, e.g. phosphates
• CPC Class Codes: C04B 24/06 containing hydroxy groups
• CPC Class Codes: C04B 28/30 containing magnesium cements or similar cementsmagnesium oxide cements C04B28/10
• CPC Class Codes: C04B 28/32 Magnesium oxychloride cements, e.g. Sorel cement
• CPC Class Codes: C04B 28/34 containing cold phosphate binders
• CPC Class Codes: C04B 28/342 the phosphate binder being present in the starting composition as a mixture of free acid and one or more reactive oxides
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4535 applied as a solution, emulsion, dispersion or suspension
• CPC Class Codes: C04B 41/5015 containing phosphorus in the anion, e.g. phosphates
• CPC Class Codes: C04B 41/67 Phosphates
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

This application relates to a treating method for magnesium oxysulfate cement (MOS) or magnesium oxychloride cement (MOC) articles. The MOS or MOC article is molded, cured and dried, then the article is treated in water soluble phosphate solution for periods of 0.5 to 90 minutes. When the MOS or MOC article is treated in water soluble phosphate solution, phosphate can penetrate into MOS or MOC article, react with the non-active magnesia remaining in MOS or MOC article to form magnesium phosphate cement (MPC). After such treatment, MOS or MOC phase is bonded by magnesium phosphate cement (MPC), many defects for MOS or MOC article, such as cracks, distortion, chalking, effloresce, poor durability, and so on, can be reduced or eliminated.

Claims

1. A method for improving the durability characteristics of a formed article of MOS or MOC, comprising:

MOS or MOC article is treated with phosphate solution.

2. The method of claim 1, wherein MOS or MOC article are formed by the intimate mixing of concentrated solutions of magnesium sulfate or magnesium chloride with magnesium oxide. MgO used to prepare MOS/MOC articles was light-burnt magnesia (LBM) powder, in which the active MgO, which can react with MgCl₂/MgSO₄, should be more than 40%. Magnesium sulfate solutions may typically contain 15 to 40 percent by weight magnesium sulfate solids. Magnesium chloride solutions used typically contain from 15 percent to 50 percent by weight solids.

3. The method of claim 2, wherein the mole ratios of active magnesium oxide to hydrated sulfate used to prepare MOS are typically in the range of between 5:

1 to 14;

1. The mole ratios of magnesium oxide to hydrated magnesium chloride are typically in the range of 5;

1 to about 8;

1.

4. The method of claim 2, wherein dead-burnt MgO can be used as fillers, the amount of dead burnt MgO is 0˜

30%.

5. The method of claim 1, wherein the phosphates can be selected from water soluble acid and/or salt of phosphate, pyrophosphate and polyphosphate, such as KH₂PO₄, NH₄H₂PO₄, NaH₂PO₄, Mg(H₂PO₄)₂, Al(H₂PO₄)₃, Zn(H₂PO₄)₂, Ca(H₂PO₄)₂, and so on, in which KH₂PO₄ and NH₄H₂PO₄ are preferred.

6. The method of claim 1, wherein the concentration of phosphate solution is 0.5˜

50%, the treating time is 0.5˜

90 minutes.