Thermal decomposition of dolomite was investigated using DTA-TG and TEM. There have two obvious endothermic valley and the first one is narrow and sharp, the second endothermic valley is wide and flat. Between the two valley there is a temperature difference about 15-20°C and no decomposition in this region. Before the decomposition of dolomite some spherical particles formed on the surface of mineral grain. The first endothermic valley formed when these particles started to decompose, and the remaining material decomposed into the second endothermic valley.

Traditional water-based flame-retardant finishing causes serious pollution due to the use of a large number of chemicals, and color change is easily generated since the flame-retardant finishing takes place after the cotton dyeing. An eco-friendly flame-retardant finishing of dyed cotton was explored using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 2,2′-oxybis-(5,5-dimethyl-1,3,2,-dioxaphosphorinane-2,2′-disulfide) (5060), SiO2, DOPO/SiO2 (1:1), 5060/SiO2 (1:1) and DOPO/5060 (1:1) in supercritical CO2. The effects of finishing time and pressure as well as temperature on the flame-retarding properties of the cotton were discussed. As expected, samples with the higher weight gain rates exhibit a lower after-flame time as well as after-glow time. In different flame-retardant systems, cotton fabric finished with DOPO presents the lowest after-flame time of 20.6 s and after-glow time of 0 s at 130°C, 22 MPa and 120 min due to its biphenyl ring and O=P-O bond. Moreover, tiny fluctuations of L*, a*, b* and K/ S values occurred from 32.10 to 34.24, 5.78 to 6.05, –37.89 to –37.64 and 10.59 to 10.81 when the cotton samples were treated with DOPO, 5060, SiO2, DOPO/SiO2 (1:1), 5060/SiO2 (1:1) and DOPO/5060 (1:1), proving that no significant negative role in the color property of the samples occurs after supercritical CO2 finishing.

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In this paper,DTA-TG and TEM are used to investigate dolomite containing phosphorus. The investigations suggest that the thermal decomposition of dolomite containing a little bit of phosphorus powder has only one reaction while that of dolomite has two reactions, and the final temperature of the reaction reduces by about 18°C. The oxidation reaction of the phosphorus in dolomite begins at about 500°C, which is 140°C higher than that of the oxidation reaction of phosphorus in standard atmosphere condition. Round-bubble-shape structure gradually appears on the surface of the dolomite sample when observed using TEM. Furthermore, the number and size of this structure increased with the rising of the temperature. Finally, the round-bubble-shape structure breaks to small hollows, showing as teared-shape, and forms a series of protruding and intensive larger hollows and spherical shape. Therefore, the temperature of thermal decomposition of thermal decomposition of dolomite is decreased and the components of thermal decomposition products of dolomite containing phosphorus are almost the same as that of dolomite.