“The use of ecological recycling technology to transform current phosphorus chemicals technology system in the world forms a new fine phosphates chemicals technology system featuring an ecological cycle. Not only can this action achieve one-time full-usage of apatite components, but also avoid the generation of gypsum and waste water.” On November 8, in the 2016 China (Deyang) Phosphorus Titanium Chemical High-end Forum hosted by China Chemical Industry Association, Sichuan Province Association, a scientific research team led by Zhang Yi, Engineer of the Chinese Academy of Engineering, Chinese Academy of Sciences, proposed a new technology system on phosphorus chemical featuring ecological cycle. With its subversive innovation concept, this research could open the door of hope for this industry which faces resourceful and environmental hazard.
Phosphorus chemical industry in the world today starts from phosphoric acid production, although there are two technical routes, hot phosphoric acid process and wet phosphoric acid process, both of them feature the use of single component of P2O5. The waste of resources and environmental pollution caused in the chemical industry is extraordinary. As the largest phosphorus chemicals producer, consumer and exporter in the world, China's phosphorus chemical industry is currently facing serious environmental pollution and waste of resources. “During ‘the Thirteenth Five-Year Plan Period’, the phosphorus chemical industry was given a target, which is to reach a situation where 95% of the “three wastes” were taken care of, and 80% of the resources were comprehensively utilized, but whether the goal can be achieved depends on the phosphorus chemical technology innovation breakthrough”, said Wen Lining, the deputy secretary general of China Inorganic Salt Industry Association.
“The main path to the transition and upgrade of phosphorus chemical industry is sustainable development, to achieve this change, we must change the traditional technology system, and around the phosphorus chemical industry and product structure adjustment must to be made to deploy technical innovation”, Hong Ding, Senior Consultant of China Chemical Industry Association, agreed.
Against such background, a new fine phosphates chemicals technology system featuring an ecological cycle was brought about by the Chinese Academy of Sciences. Compared to the current system, this is a brand-new route, which has the potential to solving the bottleneck problem of resource and environment for good. According to the introduction by the researcher, Li Zuohu, the new technology utilizes two acid and alkali production units, ammonium chloride and calcium chloride to modify current phosphoric acid producing process. Among which, ammonium chloride is decomposed into ammonia and hydrochloric acid, and calcium chloride reacts with carbon dioxide to give calcium carbonate and hydrochloric acid. These are two hydrochloric acid regeneration cycle processes which can replace the process of sulfuric acid in current system. Apatite is divided into the main product by hydrochloric acid calcium dihydrogen phosphate that is high concentrations of superphosphate fertilizer and other three bi-products: calcium carbonate, magnesium hydroxide and calcium silicate dihydrate, and this is what is called one-time full-usage of apatite components. In this process, no gypsum and waste water would be generated. And then calcium phosphate, instead of phosphoric acid, will be used to produce other fine phosphate, and then produce high purity phosphoric acid and yellow phosphorus products, which constitutes a new fine phosphorus chemical new technology system.
This technology starts from solid calcium dihydrogen phosphate instead of concentrated phosphoric acid, which will significantly reduce the cost of raw materials in this industry. “This is a brand-new route, and we hope to verify it in practice” said Zhang Yi.
As for the economics on this issue, Li Zuohu made a simple calculation, “every ton of calcium dihydrogen phosphate production will come with 0.9 ton of calcium carbonate, 0.1 ton of magnesium hydroxide and 1 ton of calcium silicate dihydrate as bi-products. The value of the three bi-products equals the main product, which means the economics will increase by 30%.”