摘要:
Process for the preparation of iron oxide pigments from the waste acid resulting from the preparation of titanium dioxide by the sulfate process, characterized in that in a first stage a partial neutralization of the sulfuric acid contained in the waste acid is performed with compounds from the group comprising metallic iron and/or iron compounds, the sulfuric acid is optionally further neutralized with a further alkaline compound, the precipitate containing Ti, Al, Cr and V compounds is separated from the resultant reaction product and an iron oxide yellow pigment or iron oxide black pigment is precipitated from the resultant iron sulfate-containing solution by addition of alkaline compounds as well as an oxidizing agent, each pigment being able to be baked to form an iron oxide red pigment.
摘要:
Process for the production of gypsum and also of an iron-oxide pigment from the waste acid that accumulates in the course of the production of titanium dioxide in accordance with the sulfate process, characterized in that in a first stage a partial neutralization of the waste acid is effected with a calcium compound subject to precipitation and optionally direct separation of gypsum, subsequently the remaining solution is neutralized further in a second stage subject to precipitation of a deposit containing Ti, Al, Cr, V and optionally Fe(III) and from the solution containing iron sulfate that is obtained after separation of the solids an iron-oxide pigment is produced in a third stage by addition of alkaline compounds and also of an oxidizing agent.
摘要:
Process for the production of gypsum and also of an iron-oxide pigment from the waste acid that accumulates in the course of the production of titanium dioxide in accordance with the sulfate process, characterized in that in a first stage a partial neutralization of the waste acid is effected with a calcium compound subject to precipitation and optionally direct separation of gypsum, subsequently the remaining solution is neutralized further in a second stage subject to precipitation of a deposit containing Ti, Al, Cr, V and optionally Fe(III) and from the solution containing iron sulfate that is obtained after separation of the solids an iron-oxide pigment is produced in a third stage by addition of alkaline compounds and also optionally addition of ammonia and also of an oxidizing agent, ammonia being liberated by addition of CaO and/or Ca(OH)2 from the solution containing (NH4)2SO4 that is obtained after separation of the iron-oxide pigment.
摘要翻译:用于生产石膏的方法以及根据硫酸盐法在二氧化钛生产过程中积聚的废酸中的氧化铁颜料的制备方法,其特征在于在第一阶段中将废酸部分中和 由钙化合物进行沉淀和任选地直接分离石膏,随后在第二阶段中进一步中和残留的溶液,沉淀含有Ti,Al,Cr,V和任选的Fe(III)的沉积物,并从 在第三阶段通过添加碱性化合物以及任选地加入氨以及氧化剂产生在固体分离出氧化铁颜料后得到的含有硫酸铁的溶液,通过添加CaO和/ 或Ca(OH)2从含有(NH 4)2 SO 4的溶液中分离出来)。
摘要:
A novel process for the continuous preparation of perfluorinated organic compounds by electrochemical fluorination of the parent non-fluorinated or partially fluorinated organic compounds using hydrogen fluoride having an arsenic content of less than about 10 ppm can be operated over a prolonged period of time without the electrode area-time yield decreasing over time.