**Acknowledgements**

the soda, soda-AQ, KP, NS and AS process, etc., successfully employed by wheat straw pulping practices for production of brown pulps or bleached pulps, among which the soda-AQ (anthraquinone) process is most commonly applied in producing the bleached pulps from

The first installation of continuous cooking system with an annual capacity of 100,000 metric tons of wheat straw pulps was successfully operated in China, scaling up an individual pulp production line capacity from non-wood materials in the world, with the tensile strength of wheat straw pulp up to 6000 m, the mid-water discharge amount of less than

/t o.d. pulp, COD less than 60 mg/L of treated effluent, and the black liquor extraction

/t pulps, and decrease by more than 60% of a traditional CEH bleaching process.

, r<sup>2</sup> = 0.910, is summarized, and it is proven that effluent from wheat straw

SO3

, HCHO, and AQ and its modified

two-stage cooking is benefited for the desilicate of black liquor

The first mid-consistency and shortened TCF bleaching sequence in the world, namely, OQPo (oxygen delignification—chelating metal ions—peroxide bleaching assisted with oxygen) sequence, was successfully commercially operated in China in 2008, with the brightness of bleached wheat straw pulps (BWSPs) of more than 80%ISO, the pulp viscosity of 653 ml/g, breaking length of more than 7000 m, less amount bleaching effluent generated

The BWSPs can be used to manufacture a wide range of paper and paperboard grades as the full or part furnishes, such as light-weighted printing paper, letterpress printing paper, typing paper, writing paper, aluminum foil base paper, cylinder polished paper, tissue and sanitary papers, white board, coated ivory board, and almost all grades of paper and

Chemi-mechanical pulps, meeting the requirement of manufacturing A-grade corrugated medium, A-grade linerboard, etc., can be produced from wheat straw using a small amount of caustic soda with advantages as high pulp yield (73.1–78.9%), good physical strength (a tensile strength of 19.49–41.27 N.m/g), and proper biodegradable effluents. A relationship between COD load (y) and pulp yield (x) of wheat straw pulping, i.e., y = 4929.58426–

chemi-mechanical pulping has a good biodegradability contrasting with that from OCC (old

from wheat straw chemical pulping line. The successful experiences for chemical recovery in China's wheat straw chemical pulping mills indicate the following: to enhance the loss of wheat straw preparation being helpful to decrease the silica content and viscosity of black liquor, rapid cooking at lower temperature preventing the degradation of cellulose and providing wheat straw chemical pulps with good physic strength and drainability, and high efficient extraction washer for black liquor added to increase the initial concentration of black liquor and to result in steam savings during thickening black liquor and also decrement of fresh water consumption in pulp washing stage. SFP lignin, a kind of lignosulfonate in the

products, can be used as a thinning and foaming agent for drilling fluids, as well as a floccu-

wheat straw, for AQ to be used in improving selectivity of delignification.

50m3

rate up to 94.6%.

236 Global Wheat Production

about 30 m3

paperboard grades.

104.0789x + 0.5883x<sup>2</sup>

The O<sup>2</sup>

corrugated container) pulping.

cooking in soda-AQ/O<sup>2</sup>

waste liquor from the pulping of wheat straw with Na<sup>2</sup>

lating agent for treating waste drilling fluids.

This work was funded the Fundamental Research Funds for the Central Non-profit Research Institution of CAF (CAFYBB2017ZX003–08) and the Le'an Scholarship Program, Shandong province, China.
