Preparation of special silicon steel grade MgO from hydromagnesite

A preparation technology of MgO powder used in special silicon steel from hydromagnesite mineral has been developed. The preparation technology includes the following steps： （1） calcining the hydromagnesite at 700-750°C for 1.5-2 h; （2） hydrating the calcined hydromagnesite to be slurry containing the solid-liquid ratio of 15-20 g？L？1; （3） acquiring Mg（HCO3）2 solution by carbonating the slurry, the carbonation temperature, CO2 pressure, and end point PH value of carbonation are less than 40°C, 0.4-0.6 MPa, and 7 respectively during the carbonation process; （4） preparing precipitated basic magnesium carbonate by thermally decomposing the Mg（HCO3）2 solution at 90-100°C; （5） obtaining the MgO product by calcining the precipitated basic magnesium carbonate at 850-950°C for 30-60 min, and adopting flowing nitrogen during the cooling process. By using this technology, more than 80wt% magnesium in hydromagnesite mineral can be extracted, and high-performance MgO products used in special silicon steel can be ob- tained.

全自动滴定仪测定卤水中硼含量分析方法探讨

文章旨在建立一种检测盐湖卤水中硼含量的方法,通过对预处理方法的精心设计,以及对滴定原理的全面考察,建立了一种简单快速,同时又具有高精确度和高回收率的分析方法。此法尤其适用于检测含硼量低的卤水。

响应面法优化原生马苏里拉干酪加工工艺

以干酪感官评分为指标,研究发酵温度、发酵终点pH值和热烫拉伸时间对原生马苏里拉干酪品质的影响,并采用响应面法优化原生马苏里拉干酪加工工艺。确定原生马苏里拉干酪的最优制作工艺为:发酵温度为33℃,发酵终点pH值为6.1,热烫拉伸时间为10 min,响应面分析模型预测的感官评定分数为94.38。在此条件下生产的原生马苏里拉干酪呈乳白色、表面光滑、具有独特的香味、组织细腻且有很好的融化性和拉伸性。

甲基橙碱度测定滴定终点颜色判断探讨

碱度是一种水的综合性指标,检测方法一般采用滴定分析,其方法虽然简单,但是滴定终点颜色的判断,对其测定结果至关重要。依据理论进行实验,将到达终点颜色的滴定样品测定pH值,得出判断滴定终点的颜色标准,并用于日常的检测分析,使测定结果能有效指导生产。