【摘要】：在翡翠寶石學(xué)研究中,合成翡翠是較少被詳細(xì)研究的領(lǐng)域。本文在運(yùn)用固相燒結(jié)法將化學(xué)原料粉末通過燒結(jié)制備合翡翠樣品的基礎(chǔ)上,詳細(xì)研究了溶膠-凝膠法制備合成翡翠粉體原料的工藝,通過正交實(shí)驗(yàn)得出了最佳工藝條件,同時(shí)進(jìn)行了后續(xù)的高溫?zé)Y(jié)和再燒結(jié)實(shí)驗(yàn)制備合成翡翠樣品的工藝研究。采用常規(guī)的寶石學(xué)研究方法、X射線粉末衍射、掃描電子顯微鏡、紅外光譜、熱重-差熱、吸收光譜及色度學(xué)測試等現(xiàn)代測試技術(shù),對合成翡翠樣品的粉體制備工藝、燒結(jié)工藝以及其礦物寶石學(xué)特征進(jìn)行了系統(tǒng)的研究和分析。實(shí)驗(yàn)結(jié)果表明,固相燒結(jié)法制得的合成翡翠樣品內(nèi)部具有大量形狀不規(guī)則的孔洞,孔洞直徑較大。固相燒結(jié)法制得樣品的元素含量百分比與硬玉接近,樣品中形成A1203與Si02的混合結(jié)構(gòu),致色元素進(jìn)入晶格而使樣品呈顯出不均勻的綠色-紫粉色。溶膠-凝膠法制備合成翡翠粉體原料的最佳工藝條件為：金屬醇鹽濃度1.0mol/L,去離子水的添加量(H2O/[Si]摩爾比)為20：1,pH值為2,水浴溫度為60℃C,致色劑含量為0.75wt%。各因素對合成翡翠粉體原料的制備結(jié)果影響程度的次序?yàn)椋簆H值金屬醇鹽濃度和水浴溫度去離子水的增加量致色劑硝酸鉻的含量。通過溶膠-凝膠法最佳工藝條件制得的合成翡翠粉料是良好的合成翡翠前驅(qū)體。溶膠-凝膠法制得的粉體原料經(jīng)高溫?zé)Y(jié)后制得合成翡翠樣品,其外觀多呈深綠色,且含有大量孔洞。這是由于部分雜質(zhì)元素氧化為氣體未能揮發(fā)而殘留在樣品內(nèi)形成的,實(shí)驗(yàn)結(jié)果指出添加助熔劑后孔洞會(huì)變少。同時(shí)結(jié)果也表明溶膠-凝膠法制得的粉體原料在其結(jié)晶溫度1000℃C時(shí)再次保溫,會(huì)得到霞石(NaAlSiO4)結(jié)構(gòu),而非硬玉結(jié)構(gòu),這是由于硬玉是典型的高壓礦物,在常壓下是一種亞穩(wěn)態(tài),易分解為NaAlSiO4和Si02,即NaAlSi2O6 →NaAlSiO4+SiO2。通過比較溶膠-凝膠法合成翡翠樣品與固相燒結(jié)法合成翡翠樣品的顏色外觀、基本寶石學(xué)性質(zhì)以及物相組成與結(jié)構(gòu)等,表明溶膠-凝膠法較固相燒結(jié)法更適合制備合成翡翠。為了達(dá)到實(shí)驗(yàn)效果,在燒結(jié)實(shí)驗(yàn)的基礎(chǔ)上進(jìn)行了溶膠-凝膠法合成翡翠的再燒結(jié)實(shí)驗(yàn)。結(jié)果表明再燒結(jié)樣品的致密度明顯提高,內(nèi)部具分布均勻的細(xì)小孔洞,樣品呈現(xiàn)黃綠色,顏色飽和度較高,明度略低。再燒結(jié)樣品內(nèi)可析出NaAlSiO4晶體,其元素的含量百分比與硬玉基本相同,且紅外光譜與硬玉類似,但合成者的吸收帶寬化且分裂較差。
[Abstract]:In the research of jadeite gemstone, synthetic jadeite is seldom studied in detail. In this paper, based on the preparation of jadeite powder by solid phase sintering, the process of synthesizing jadeite powder by sol-gel method is studied in detail. The optimum technological conditions are obtained by orthogonal experiment. At the same time, the process of synthesizing jadeite samples by high temperature sintering and re-sintering was studied. The preparation technology of jadeite powder was studied by means of X-ray powder diffraction (XRD), scanning electron microscope (SEM), infrared spectroscopy (IR), thermogravimetric differential thermogravimetry (TG-DTA), absorption spectrum and colorimetry. The sintering process and its mineral gemstone characteristics were systematically studied and analyzed. The experimental results show that there are a large number of irregular holes in the samples of synthetic jadeite by solid phase sintering, and the diameter of the pores is large. The percentage of elements in the samples obtained by solid-phase sintering method was close to that of jadeite. The mixed structure of A1203 and Si02 was formed in the samples. The chromizing elements entered the lattice and made the samples appear inhomogeneous green and purple pink. The optimum conditions for the preparation of jadeite powder by sol-gel method are as follows: the concentration of metal alcohol is 1.0 mol / L, the molar ratio of deionized water (H2O/ [Si]) is 20: 1 (pH = 2), the water bath temperature is 60 鈩，

本文編號：2216888