Abstract

A large amount of research publications and analytical data, concerning gypsum-bearing wastes (GSW) gives an understanding of their huge volumes in many countries, as well as the urgent need to find solutions and opportunities that open up in the development and implementation of effective technologies for the disposal of GSW in various areas of the construction industry. In this paper, the review of actual technological approaches for recycling of GSW in the framework of such field of utilization as a gypsum binder production. It was found, that application of traditional technologies of synthesis of binders, containing natural raw materials is not reasonable for GSW-bearing binders due to variation in component composition, high concentration of impurities, and high dispersion. For this reason, the most advanced technologies proposed by various researchers provide for measures to correct these shortcomings or involve the synthesis of the final product - a high-quality gypsum binder, which is based on different principles - growing crystals of the desired geometry and properties in salt and acid solutions. These technologies are characterized by complexity, a negative impact on equipment, and personnel. In addition, they lead to the formation of secondary waste, which reduces the attractiveness of their practical implementation. Synthesis of GSW-bearing binders using the method of calcining is the simplest technologically and organizationally, but the binders are characterized by unsatisfactory physical and mechanical properties. The desired way to increase their profitability and investment attractiveness is the possibility of providing comprehensive processing of raw materials, where the final product will be not only binders but also other conditioned products, taking into account the minimum formation of secondary waste. The development of such technology of GSW recycling and its implementation on a commercial scale will allow increasing the volume of GSW recycling as well as to solve the ecological aspects and to expand the raw materials source base in regions where this problem is actual

Highlights

  • The most advanced technologies proposed by various researchers provide for measures to correct these shortcomings or involve the synthesis of the final product - a high-quality gypsum binder, which is based on different principles - growing crystals of the desired geometry and properties in salt and acid solutions

  • The desired way to increase their profitability and investment attractiveness is the possibility of providing comprehensive processing of raw materials, where the final product will be binders and other conditioned products, taking into account the minimum formation of secondary waste

  • Технологии производства гипсовых вяжущих материалов из фосфогипса // Вісник ПДАБА

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Summary

СТРОИТЕЛЬСТВО И АРХИТЕКТУРА

В работе [32] исследовалась возможность получения α-полугидрата из фосфогипса (Sinopharm Chemical Reagent Co., Ltd., Шанхай, Китай) в растворе CaCl2, при этом качестве кристаллического модификатора для регулирования морфологии полугидрата была рассмотрена L-аспарагиновая кислота (L-Asp). Эксперимент проводился на пилотной установке, процесс производства состоял из нескольких этапов : 1 – приготовление солевого раствора из трех видов солей (25 мас.% CaCl2, 2,0 мас.% MgCl2 ·6H2O и 1,0 мас.% KCl); 2 – введение FGD-гипса в раствор и воды с целью получения 15-25 мас.% гипсовой суспензии; 3 – обработка паром с давлением 0,8 МПа и температурой 250 °С в специальной установке, с последующем поддержанием постоянной температуры 94 °С (± 2 ° С); 4 – введение модификаторов Na2B4O7·5H2O и C4H6O4; 5 – отбор проб для промежуточного контроля до подтверждения факта получения α-полугидрата; 6 – перемещение продукта в циклон с целью разделения путем промывки и фильтрации. Достоинства и недоставки способов производства гипсовых вяжущих из отходов промышленности

Синтез при повышенных температурах и атмосферном давлении
БИБЛИОГРАФИЧЕСКИЙ СПИСОК
Construction and Building
Full Text
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